JP2009298915A - Method for bonding and bonded body - Google Patents

Abstract

A joining method capable of joining two substrates firmly with high dimensional accuracy and efficiently at low temperature, and further electrically connecting conductive portions provided on each substrate, and To provide a joined body obtained by joining the two base materials while electrically connecting the two base materials by such a joining method.
A bonding method according to the present invention includes a step of preparing a base material 21 provided with a wiring pattern 212 and a base material 22 provided with a wiring pattern 222; A step of forming the liquid coating 31 containing the particles 32, a step of superimposing the base material 21 and the base material 22 through the liquid coating 31 to form the temporary joined body 5, and electrophoresis of the conductive particles 32. A step of unevenly distributing between the wiring patterns 212 and 222, a step of drying the liquid coating 31 to obtain the bonding film 3, and applying energy to the bonding film 3, thereby causing the bonding film 3 to exhibit adhesiveness. And joining the base material 21 and the base material 22 to obtain the joined body 1.
[Selection] Figure 2

Description

  The present invention relates to a joining method and a joined body.

Conventionally, solder is widely used as a connecting material for connecting electrodes of electronic components and wiring patterns in mounting processes in various electronic devices. However, solder is disadvantageous for high-density mounting because of limitations in mounting temperature, mounting electrode pitch, mounting height, and the like.
On the other hand, an anisotropic conductive adhesive composition in which conductive particles are dispersed in a thermosetting resin has been proposed (see, for example, Patent Document 1). Since the anisotropic conductive adhesive composition has a lower processing temperature required for connection than solder, thermal degradation of electronic components can be suppressed during connection. In addition, the anisotropic conductive adhesive composition exhibits conductivity only in the thickness direction when compressed, and retains insulation in the surface direction. For example, the anisotropic conductive adhesive composition has a plurality of parallel arrangements at a narrow pitch. When electrodes are connected together, adjacent electrodes can be electrically connected while adjacent electrodes can be insulated. Further, by applying such an anisotropic conductive adhesive composition in advance to one of the electrodes to be bonded, it is possible to bond to the opposing electrode without strict alignment. Therefore, the electrode pitch can be set relatively narrow. Further, it is easy to connect a plurality of electrodes together, and the thickness can be reduced compared to solder. For these reasons, the anisotropic conductive adhesive composition has attracted attention as a connection material suitable for high-density mounting.

An anisotropic conductive film obtained by applying this anisotropic conductive adhesive composition on a release film is also used.
However, such an anisotropic conductive adhesive composition has the following problems.
・ Low adhesive strength ・ Long curing time required a long time to bond ・ Low durability against organic solvents These problems are all related to thermosetting resin materials contained in anisotropic conductive adhesive compositions It is not easy to solve because it is due to its own characteristics.

JP 7-268303 A

  The object of the present invention is to join two substrates firmly with high dimensional accuracy and efficiently at low temperature, and further to electrically connect the conductive parts provided on each substrate. And, it is to provide a joined body formed by joining the two base materials while being electrically connected by the joining method.

Such an object is achieved by the present invention described below.
In the bonding method of the present invention, a first base material having a first conductive portion on the surface and a second base material having a second conductive portion on the surface are bonded as base materials to be bonded via a bonding film. A first step to be prepared;
A second step of forming a liquid film by supplying a liquid material containing a silicone material and conductive particles on the surface of at least one of the first substrate and the second substrate;
By applying at least one of an electric field and a magnetic field to the liquid coating, the conductive particles are migrated, and the conductive particles are placed between the first conductive portion and the second conductive portion in the liquid coating. A third step of uneven distribution in the region of
A fourth step of drying the liquid film to obtain the bonding film;
By giving energy to the bonding film, the bonding film is made to exhibit adhesiveness, and a bonded body in which the first base material and the second base material are bonded via the bonding film is obtained. And a fifth step of electrically connecting the first conductive portion and the second conductive portion via the conductive particles in the bonding film.
Thereby, two base materials can be joined firmly with high dimensional accuracy and efficiently at a low temperature, and the two base materials can be electrically connected.

In the bonding method of the present invention, it is preferable that the main skeleton of the silicone material is composed of polydimethylsiloxane.
Such a compound is relatively easily available and inexpensive, and by applying energy to a bonding film containing such a compound, the methyl group constituting the compound is easily cleaved, resulting in bonding. Since the film can surely exhibit adhesiveness, it is suitably used as a silicone material.

In the bonding method of the present invention, the silicone material preferably has a silanol group.
As a result, when the liquid material is dried to obtain a bonding film, the hydroxyl groups of the adjacent silicone materials are bonded to each other, and the film strength of the obtained bonding film is excellent.
In the bonding method of the present invention, the energy is applied to the bonding film to cause the bonding film to exhibit adhesiveness, and then the first base material and the second base material are interposed through the bonding film. It is preferable to obtain the joined body by superimposing.
Thereby, since it is sufficient to perform the operation of superimposing the first base material and the second base material through the solid bonding film, it is possible to reliably prevent problems such as liquid dripping and adhesion of the liquid film. it can.

In the bonding method of the present invention, the first base material and the second base material are overlapped via the bonding film, and then the energy is applied to the bonding film to obtain the bonding film. It is preferable.
Since the first base material and the second base material are not joined in the state of the temporary joined body in which the first base material and the second base material are simply overlapped, the positions of the first base material and the second base material can be easily set. Can be adjusted. Therefore, once the first base material and the second base material are overlapped, the relative position of these can be shifted and finely adjusted, and the dimensional accuracy of the finally obtained joined body can be further increased. Can be increased.

In the bonding method of the present invention, the conductive particles are charged,
In the third step, the conductive particles are preferably electrophoresed by applying an electric field to the liquid film.
Thereby, electrophoretic phenomenon can be utilized to make the conductive particles unevenly distributed in a predetermined region (between the first conductive portion and the second conductive portion).

In the bonding method of the present invention, in the third step, a voltage is applied between the first conductive portion and the second conductive portion, whereby the conductive particles are bonded to the first conductive portion. And the second conductive part are preferably unevenly distributed.
Thereby, it is not necessary to separately provide an electrode for generating an electric field, and the uneven distribution of conductive particles can be easily performed.

In the bonding method of the present invention, the conductive particles preferably include base particles and a metal film that covers the surface of the base particles.
This makes it easy to adjust the shape, size (average particle size, etc.) and physical properties (conductivity, density, etc.) of the conductive particles by appropriately selecting the constituent material of the base particles and the constituent material of the conductive film. It becomes.
In the bonding method of the present invention, it is preferable that the conductive film is composed mainly of Ni, Cu or Au.
Since these conductive materials are excellent in conductivity, highly conductive particles can be obtained, and the conductivity between the first conductive portion and the second conductive portion can be increased.

In the bonding method of the present invention, it is preferable that the base particles are made of a resin material.
Since the resin material is generally close to the specific gravity of the silicone material, the conductive particles are unlikely to settle or float in the liquid material. That is, conductive particles that can be uniformly dispersed in a liquid material can be obtained. Moreover, since the specific gravity of the resin material is relatively small, conductive particles capable of rapid migration can be obtained.

In the bonding method of the present invention, the conductive particles are made of a ferromagnetic material,
In the third step, the conductive particles are preferably subjected to magnetophoresis by applying a magnetic field to the liquid coating.
Thereby, electroconductive particle is magnetized by the effect | action of a magnetic field, and becomes a magnet itself. As a result, the plurality of conductive particles can be arranged along the magnetic field, and the arranged plurality of conductive particles can function as a highly conductive wiring.

In the bonding method of the present invention, the ferromagnetic material preferably contains Fe, Co, or Ni.
Since such a ferromagnetic material has high conductivity, a highly conductive bonding film is finally obtained.
In the bonding method of the present invention, it is preferable that the conductive particles have elasticity.
Thereby, the electroconductive particle which can be deform | transformed into a flat shape easily by giving a compressive force is obtained. Therefore, by using flexible particles as the conductive particles, the conductive particles are easily flattened between the first conductive portion and the second conductive portion, so that the first conductive portion and the second conductive portion The contact area of the conductive particles with respect to the portion can be increased. As a result, in the joined body, the conductivity between the conductive parts can be further increased. Further, since the conductive particles have flexibility, even when the particle diameter of the conductive particles is not uniform, the variation in the particle diameter can be compensated for by the deformation of the conductive particles. Furthermore, even when the surface of each conductive portion is uneven, the conductive particles can be reliably brought into contact with each other by deformation of the conductive particles.

In the bonding method of the present invention, the conductive particles preferably have an average particle size of 0.5 to 100 μm.
Thereby, aggregation of conductive particles can be prevented in the liquid material. Moreover, it can prevent that the average particle diameter of electroconductive particle is too large, and the probability that electroconductive particles and electroconductive particle and each base material will contact in a liquid film will become high.

In the bonding method of the present invention, the content of the conductive particles in the bonding film is preferably 1 to 50% by mass.
This makes it difficult to fill the gap between the first conductive portion and the second conductive portion with the conductive particles, and prevents the conductivity between them from decreasing, while preventing the liquid film from being unintentionally conductive. It is possible to prevent the anisotropic conductivity from being impaired.

In the bonding method of the present invention, the first base material protrudes from a surface located on the bonding film side of the first insulating substrate as the first insulating substrate and the first conductive portion. A first conductive film provided as follows:
The second base is provided as a second insulating substrate and a second conductive portion that protrudes from a surface located on the bonding film side of the second insulating substrate. And a conductive film of
The first base material and the second base material are joined through the joint film, and the first conductive film and the second base material are joined through the conductive particles in the joint film. It is preferable to selectively electrically connect the conductive film.
Thereby, in the temporary joined body formed by superimposing the first base material and the second base material, the separation distance between the first insulating substrate and the second insulating substrate is the same as the first conductive portion. It is larger than the distance from the second conductive portion. Therefore, in the temporary joined body, the probability that the conductive particles are in contact with the first insulating substrate and the second insulating substrate is particularly low. For this reason, it will be in an insulation state between the 1st insulating substrate and the 2nd insulating substrate. From the above, the liquid film or the bonding film has conductivity in the thickness direction and has insulation in the surface direction, that is, has so-called anisotropic conductivity.

In the bonding method of the present invention, the conductive particles in the bonding film selectively electrically connect regions facing each other in the first conductive film and the second conductive film. It is preferable.
Thereby, only the area | region which mutually opposes between the 1st electrically conductive film and the 2nd electrically conductive film can conduct | electrically_connect, and an area | region other than that can be insulated. As a result, for example, when electrodes having the same pattern are connected to each other, the electrodes facing each other can be connected and the electrodes not facing each other can be insulated, so that circuit formation can be easily performed.

In the bonding method of the present invention, the application of the energy in the fifth step includes a method of irradiating the bonding film with energy rays, a method of heating the bonding film, and a method of applying a compressive force to the bonding film. It is preferable to carry out by at least one of these methods.
Thereby, the surface of the bonding film can be activated efficiently. In addition, since the molecular structure in the bonding film is not cut more than necessary, it is possible to avoid deterioration of the characteristics of the bonding film.

In the bonding method of the present invention, the energy beam is preferably ultraviolet light having a wavelength of 126 to 300 nm.
By using ultraviolet rays within the above range as energy rays, the amount of energy applied is optimized, so that the molecular bond forming the skeleton in the bonding film is prevented from being destroyed more than necessary, and from the bonding film. Molecular bonds near the surface can be selectively broken. Thereby, adhesiveness can be reliably expressed in the bonding film while preventing deterioration of the characteristics of the bonding film.

In the bonding method of the present invention, the heating temperature is preferably 25 to 100 ° C.
Thereby, it is possible to reliably increase the bonding strength while reliably preventing the bonded body from being deteriorated and deteriorated by heat.
In the joining method of the present invention, the compressive force is preferably 0.2 to 10 MPa.
Accordingly, it is possible to reliably increase the bonding strength of the bonded body while preventing the substrate from being damaged due to the pressure being too high.

In the bonding method of the present invention, it is preferable that the application of energy in the fifth step is performed in an air atmosphere.
Thereby, it is not necessary to spend time and cost to control the atmosphere, and energy can be applied more easily.
In the bonding method of the present invention, the average thickness of the bonding film is preferably 100 nm to 100 μm.
Thereby, the 1st base material and the 2nd base material can be joined more firmly, preventing the dimensional accuracy of a joined object falling remarkably.

In the bonding method of the present invention, in the second step, the liquid film is formed on the surfaces of both the first base material and the second base material,
In the fifth step, it is preferable that the first base material and the second base material are overlapped so that the liquid coatings are in close contact with each other.
Thereby, between the 1st substrate and the 2nd substrate can be joined more firmly.

In the joining method of this invention, it has the process of performing the process which raises the joint strength of a said 1st base material and a said 2nd base material with respect to the said conjugate | zygote further after the said 5th process. Is preferred.
Thereby, the joint strength of the joined body can be further improved.
In the bonding method of the present invention, the step of increasing the bonding strength includes a method of irradiating the bonding film with energy rays, a method of heating the bonding film, and a method of applying compressive force to the bonding film. It is preferable to carry out by at least one method.
Thereby, the further improvement of the joining strength of a joined body can be aimed at easily.

In the joined body of the present invention, the first base material and the second base material each have a conductive portion on a surface facing each other,
The first base material and the second base material are joined by the joining method according to any one of claims 1 to 26, and the conductive portions are electrically connected. It is characterized by.
Thereby, the joined body formed by joining while electrically connecting two base materials is obtained.

Hereinafter, a joining method and a joined object of the present invention are explained in detail based on a suitable embodiment shown in an accompanying drawing.
The joining method of the present invention is a method of joining and electrically connecting two base materials (first base material 21 and second base material 22) via bonding films 3, 3 ′. is there.
The bonding films 3 and 3 ′ are films mainly composed of a composite in which conductive particles are dispersed in a silicone material. By applying energy, the bonding films 3 and 3 ′ are bonded to a region to which surface energy is applied. It has the characteristic that sex is expressed.
According to the bonding films 3 and 3 ′ having such characteristics, the two base materials 21 and 22 can be bonded with high dimensional accuracy firmly and efficiently at a low temperature, and can be electrically connected. Is possible. And according to this invention, the two base materials 21 and 22 are joined firmly, and the joining body 1 with high reliability formed by electrically connecting is obtained.

<Join method>
<< First Embodiment >>
First, the first embodiment of the bonding method of the present invention and the bonded body of the present invention will be described.
1 and 2 are views (longitudinal sectional views) for explaining a first embodiment of the joining method of the present invention. In the following description, the upper side in FIGS. 1 and 2 is referred to as “upper” and the lower side is referred to as “lower”.

In the bonding method according to the present embodiment, the first base material 21 and the second base material 22 are prepared, and the bonding film forming region 41 on the first base material 21 is electrically conductive in the silicone material. A process of forming a liquid coating 31 by supplying a liquid material 30 in which particles 32 are dispersed, and a first substrate 21 and a second substrate 22 are overlapped with each other via the liquid coating 31 to temporarily bond the bonded body. 5, the step of causing the conductive particles 32 to migrate by applying an electric field to the liquid coating 31, the conductive particles 32 being unevenly distributed in a predetermined region, and the drying of the liquid coating 31 in the temporary joined body 5. Then, the step of obtaining the bonding film 3 and the application of energy to the bonding film 3 cause the adhesiveness to develop near the front surface and the back surface of the bonding film 3. To obtain a joined body 1.
Hereinafter, each process of the joining method concerning this embodiment is demonstrated one by one.

[1] First, a first base material 21 and a second base material 22 are prepared.
The first base material 21 and the second base material 22 to be joined by the joining method of the present invention may be composed of any material, but in this embodiment, as shown in FIG. In addition, the first base material 21 is composed of an insulating substrate 211 (first insulating substrate) and three conductive films 212a (first conductive films) provided on a part of the surface thereof. In addition, the second base material 22 includes an insulating substrate 221 (second insulating substrate) and three conductive films 222a (second conductive films) provided on a part of the surface thereof. Has been. Note that the conductive films 212a and the conductive films 222a have conductivity, and the conductive films 212a and the conductive films 222a are provided apart from each other.

  Each of the three conductive films 212a has a strip shape, and the first wiring pattern 212 is configured by arranging the strip-shaped conductive films 212a in a stripe shape. On the other hand, each of the three conductive films 222a has a strip shape, and the second conductive pattern 222 is formed by arranging the strip-shaped conductive films 222a in a stripe shape. The first wiring pattern 212 and the second wiring pattern 222 have substantially the same size and pitch, and each conductive film 212a and each conductive film corresponding to the conductive film 212a are subjected to the processes described later. 222a is electrically connected through a bonding film.

The conductive material constituting each conductive film 212a and each conductive film 222a is not particularly limited as long as it is substantially conductive. For example, copper, aluminum, nickel, cobalt, platinum, gold, Metal materials such as silver, molybdenum, tantalum or alloys containing them, carbon-based materials such as carbon black, carbon nanotubes, fullerene, polyacetylene, polypyrrole, polythiophene, polyaniline, poly (p-phenylene), poly (p-phenylene vinylene) An ionic substance is dispersed in an electroconductive polymer material such as polyfluorene, polycarbazole or derivatives thereof, or a matrix resin such as polyvinyl alcohol, polycarbonate, polyethylene oxide, polyvinyl butyral, polyvinyl carbazole, or vinyl acetate. The ion conductive polymer material was indium tin oxide (ITO), fluorine-doped tin oxide (FTO), tin oxide (SnO _2), indium oxide (IO) as a conductive oxide material such as Various types of conductive materials can be used, and one or more of these can be used in combination.
In addition, as the conductive material, for example, a conductive material (conductive particles) such as gold, silver, nickel, and carbon in a non-conductive material such as a glass material, a rubber material, and a polymer material. It is also possible to use various composite materials that are mixed with each other to add conductivity.

  The constituent materials of the insulating substrate 211 and the insulating substrate 221 are not particularly limited, but polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), cyclic polyolefin, Modified polyolefin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, polyamideimide, polycarbonate, poly- (4-methylpentene-1), ionomer, acrylic resin, polymethyl methacrylate, acrylonitrile-butadiene-styrene copolymer Copolymer (ABS resin), acrylonitrile-styrene copolymer (AS resin), butadiene-styrene copolymer, polyoxymethylene, polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer (EVOH), polyethylene terephthalate (PET), polyethylene naphthalate, polybutylene terephthalate (PBT), polyester such as polycyclohexane terephthalate (PCT), polyether, polyether ketone (PEK), polyether ether ketone (PEEK), poly Ether imide, polyacetal (POM), polyphenylene oxide, modified polyphenylene oxide, polysulfone, polyether sulfone, polyphenylene sulfide, polyarylate, aromatic polyester (liquid crystal polymer), polytetrafluoroethylene, polyvinylidene fluoride, other fluororesins, Styrene, polyolefin, polyvinyl chloride, polyurethane, polyester, polyamide, polybutadiene, Various thermoplastic elastomers such as polyisoprene, fluororubber, chlorinated polyethylene, epoxy resin, phenol resin, urea resin, melamine resin, aramid resin, unsaturated polyester, silicone resin, polyurethane, etc. Copolymers, blends, resin materials such as polymer alloys, metal materials such as gallium arsenide, silicate glass (quartz glass), alkali silicate glass, soda lime glass, potash lime glass, lead (alkali) ) Glass materials such as glass, barium glass, borosilicate glass, ceramics such as alumina, zirconia, ferrite, silicon nitride, aluminum nitride, boron nitride, titanium nitride, silicon carbide, boron carbide, titanium carbide, tungsten carbide Material, or one of each of these materials The composite material etc. which combined seed | species or 2 or more types are mentioned.

In addition, as a constituent material of the semiconductor substrate, an elemental semiconductor such as single crystal silicon, polycrystalline silicon, and amorphous silicon, a compound semiconductor such as gallium arsenide, or one or more of these materials may be used. The composite material etc. which were combined are mentioned.
Each of these insulating substrate 211 and insulating substrate 221 may have its surface subjected to passivation treatment such as chromate treatment or nitriding treatment.

Note that the configuration of the first base material 21 and the configuration of the second base material 22 may be the same or different.
Moreover, it is preferable that the thermal expansion coefficient of the 1st base material 21 and the thermal expansion coefficient of the 2nd base material 22 are substantially equal. If these thermal expansion coefficients are substantially equal, when the first base material 21 and the second base material 22 are joined, it is difficult for stress associated with thermal expansion to occur at the joint interface. As a result, peeling can be reliably prevented in the finally obtained bonded body 1.

In addition, although it explains in full detail later, even when the thermal expansion coefficient of the 1st base material 21 and the thermal expansion coefficient of the 2nd base material 22 mutually differ, in the process mentioned later, the 1st base material 21 and 2nd By optimizing the conditions for joining the base material 22, these can be firmly joined with high dimensional accuracy.
Moreover, it is preferable that at least one of the two base materials 21 and 22 is made of a resin material as a main material. The resin material can relieve stress (for example, stress accompanying thermal expansion) generated at the bonding interface when the two base materials 21 and 22 are bonded due to its flexibility. For this reason, it becomes difficult to destroy the bonding interface, and as a result, the bonded body 1 having high bonding strength can be obtained.

In view of the above, at least one of the two base materials 21 and 22 preferably has flexibility. Thereby, the joint strength of the joined body 1 can be further improved. Furthermore, when both the two base materials 21 and 22 have flexibility, the joined body 1 which has flexibility as a whole and high functionality can be obtained.
Moreover, the shape of each base material 21 and 22 should just be a shape which has the surface which supports a liquid film, respectively, For example, it is set as plate shape (layer shape), lump shape (block shape), rod shape, etc.

Since each base material 21 and 22 is each plate-shaped, each base material 21 and 22 becomes easy to bend, and when two base materials 21 and 22 are piled up, it is fully along each other's shape. It can be deformed. For this reason, the adhesiveness when the two base materials 21 and 22 are overlapped is increased, and the bonding strength in the finally obtained bonded body 1 is increased.
In addition, it is expected that the base material 21 and 22 are bent to alleviate the stress generated at the joint interface to some extent.

In this case, the average thickness of each of the base materials 21 and 22 is not particularly limited, but is preferably about 0.01 to 10 mm, and more preferably about 0.1 to 3 mm.
In addition, in this embodiment, as shown to Fig.1 (a), each base material 21 and 22 has each comprised plate shape, Among these, one main surface (joining surface 23) of the 1st base material 21 is mentioned. A region excluding the peripheral portion is set as a bonding film forming region 41 where the bonding film 3 is formed. Here, it is assumed that the bonding film formation region 41 overlaps a part of each conductive film 212 a constituting the first wiring pattern 212.

  Next, if necessary, a surface treatment for improving the adhesion with the bonding film 3 is performed on the bonding surface 23 of the first base material 21, that is, the upper surfaces of the first insulating substrate 211 and the conductive films 212 a. Thereby, the bonding surface 23 is cleaned and activated, and the bonding film 3 easily acts on the bonding surface 23 chemically. As a result, when the bonding film 3 is formed on the bonding surface 23 in a process described later, the bonding strength between the bonding surface 23 and the bonding film 3 can be increased. In addition, the electrical resistance between each conductive film 212a and the bonding film 3 can be reduced.

This surface treatment is not particularly limited, for example, physical treatment such as sputtering treatment, blast treatment, plasma treatment using oxygen plasma, nitrogen plasma, corona discharge treatment, etching treatment, electron beam irradiation treatment, Examples thereof include a chemical surface treatment such as ultraviolet irradiation treatment, ozone exposure treatment, or a combination thereof.
In addition, when the 1st insulating board | substrate 211 which performs surface treatment is comprised with the resin material (polymer material), especially a corona discharge process, a nitrogen plasma process, etc. are used suitably.

In addition, the bonding surface 23 can be further cleaned and activated by performing plasma treatment or ultraviolet irradiation treatment as the surface treatment. As a result, the bonding strength between the bonding surface 23 and the bonding film 3 can be particularly increased. In addition, the electrical resistance between each conductive film 212a and the bonding film 3 can be particularly reduced.
In addition, depending on the constituent materials of the first insulating substrate 211 and the first wiring pattern 212, there are those in which the bonding strength with the bonding film 3 is sufficiently high without performing the surface treatment as described above. Examples of the constituent material of the first insulating substrate 211 that can obtain such an effect include materials mainly composed of various silicon-based materials, various glass-based materials, and the like. Examples thereof include those mainly composed of various metal-based materials.

The surface of the first base material 21 made of such a material is covered with an oxide film, and a hydroxyl group is bonded to the surface of the oxide film. Therefore, by using the first base material 21 covered with such an oxide film, the bonding surface 23 of the first base material 21 and the bonding film 3 are not subjected to the surface treatment as described above. Bonding strength can be increased.
In this case, the entire first insulating substrate 211 and the first wiring pattern 212 may not be made of the material as described above, and at least the vicinity of the bonding surface 23 is made of the material as described above. It only has to be.

Instead of the surface treatment, an intermediate layer may be formed in advance on the bonding surface 23 of the first base material 21.
The intermediate layer may have any function. For example, a layer having a function of improving adhesion to the bonding film 3, a cushioning function (buffer function), a function of reducing stress concentration, and the like are preferable. By forming the bonding film 3 on such an intermediate layer, a highly reliable bonded body 1 can be finally obtained.

  Examples of the constituent material of the intermediate layer include metal materials such as aluminum and titanium, metal oxides, oxide materials such as silicon oxide, metal nitrides, and nitride materials such as silicon nitride. Carbon materials such as graphite and diamond-like carbon, silane coupling agents, thiol compounds, metal alkoxides, self-assembled film materials such as metal-halogen compounds, resin adhesives, resin films, resin coating materials, Various rubber materials, resin materials such as various elastomers, and the like can be used, and one or more of these can be used in combination.

Further, among the intermediate layers formed of these materials, the intermediate layer formed of the oxide-based material can particularly increase the bonding strength between the first base material 21 and the bonding film 3. it can.
The intermediate layer as described above may be provided on both the surface of the first insulating substrate 211 and the surface of the first wiring pattern 212 in the bonding surface 23, or on either one of them. Also good. Moreover, when providing an intermediate | middle layer in both the surface of the 1st insulating board | substrate 211 and the surface of the 1st wiring pattern 212, the intermediate | middle layer provided in each surface may be the same or different. The intermediate layer provided on each surface is preferably selected in consideration of its conductivity. That is, it is preferable to provide an insulating intermediate layer on the surface of the first insulating substrate 211 and to provide a conductive intermediate layer on the surface of the first wiring pattern 212.

On the other hand, as with the first base material 21, the bonding surface 24 of the second base material 22, that is, the second insulating substrate 221 and each conductive film 222 a are adhered to the bonding film 3 in advance as necessary. A surface treatment for enhancing the properties may be performed. Thereby, the bonding surface 24 is cleaned and activated. As a result, the bonding strength between the bonding surface 24 of the second base material 22 and the bonding film 3 can be increased.
Although it does not specifically limit as this surface treatment, The process similar to the surface treatment with respect to the joint surface 23 of the above-mentioned 1st base material 21 can be used.

  Similarly to the case of the first base material 21, depending on the constituent materials of the second insulating substrate 221 and the second wiring pattern 222, the bonding film 3 and the bonding film 3 can be formed without performing the surface treatment as described above. Some have sufficiently high adhesion. Examples of the constituent material of the second insulating substrate 221 that can obtain such an effect include those mainly composed of various silicon-based materials and various glass-based materials as described above. As a constituent material of the pattern 222, for example, a material mainly composed of various metal-based materials as described above can be used.

That is, the surface of the second substrate 22 made of such a material is covered with an oxide film, and hydroxyl groups are bonded to the surface of the oxide film. Therefore, by using the second base material 22 covered with such an oxide film, the bonding surface 24 of the second base material 22 and the bonding film 3 can be formed without performing the surface treatment as described above. Bonding strength can be increased.
In this case, the entire second insulating substrate 221 and the second wiring pattern 222 do not have to be made of the material as described above, and at least the vicinity of the bonding surface 24 is made of the material as described above. It only has to be.
Further, when the bonding surface 24 of the second base material 22 includes the following groups and substances, the bonding surface 24 and the bonding film of the second base material 22 are not subjected to the surface treatment as described above. 3 can be sufficiently increased in bonding strength.

  Examples of such groups and substances include various functional groups such as hydroxyl group, thiol group, carboxyl group, amino group, nitro group, and imidazole group, various radicals, ring-opening molecules, double bonds, and triple bonds. At least one group or substance selected from the group consisting of a leaving intermediate molecule having an unsaturated bond, a halogen such as F, Cl, Br, and I, a peroxide, or the group is desorbed. An unterminated bond (an unbonded bond, a dangling bond) is provided.

Of these, the leaving intermediate molecule is preferably a ring-opening molecule or a hydrocarbon molecule having an unsaturated bond. Such hydrocarbon molecules act strongly on the bonding film 3 based on the remarkable reactivity of ring-opening molecules and unsaturated bonds. Therefore, the bonding surface 24 having such hydrocarbon molecules can be bonded to the bonding film 3 particularly firmly.
The functional group possessed by the bonding surface 24 is particularly preferably a hydroxyl group. Thereby, the bonding surface 24 can be bonded to the bonding film 3 particularly easily and firmly.

In addition, the second base capable of being strongly bonded to the bonding film 3 by appropriately selecting and performing various surface treatments as described above on the bonding surface 24 so as to have such a group or substance. A material 22 is obtained.
Among these, it is preferable that the bonding surface 24 of the second base material 22 has a hydroxyl group. A large attractive force based on the hydrogen bond is generated between the bonding surface 24 and the bonding film 3 from which the hydroxyl group is exposed. Thereby, finally, the first base material 21 and the second base material 22 can be bonded particularly firmly.
Further, instead of the surface treatment, an intermediate layer may be formed in advance on the bonding surface 24 of the second base material 22.

The intermediate layer may have any function. For example, as in the case of the first base material 21, the intermediate layer has a function of improving adhesion to the bonding film 3, a cushioning property (buffer function), a stress. What has the function etc. which ease concentration is preferable.
As the constituent material of the intermediate layer, for example, the same material as the constituent material of the intermediate layer formed on the bonding surface 23 of the first base member 21 can be used.
Further, the surface treatment and the formation of the intermediate layer may be performed as necessary, and can be omitted when a high bonding strength is not particularly required.

[2] Next, as shown in FIG. 1B, the liquid material 30 containing the silicone material and the conductive particles 32 is supplied to the bonding film forming region 41 of the first base material 21 to form the bonding film. A liquid film 31 is formed in the region 41.
Specifically, a mask having a window portion having a shape corresponding to the shape of the bonding film forming region 41 is provided on the first base material 21, and a liquid material is supplied through the mask. In this way, the liquid material is selectively supplied to the bonding film formation region 41, and the liquid film 31 is formed in the bonding film formation region 41.

Examples of a method for supplying the liquid material 30 to the bonding film forming region 41 include an inkjet method, a spin coating method, a casting method, a micro gravure coating method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, Various coating methods such as a dip coating method, a spray coating method, a screen printing method, a flexographic printing method, an offset printing method, and a microcontact printing method can be mentioned, and one or more of these can be used in combination. it can. Of these, the inkjet method is preferably used. According to such a method, the liquid material can be selectively supplied to the bonding film forming region 41 of the first base member 21 with relative ease and excellent accuracy.
Thereafter, the mask is removed using various etching methods.

Alternatively, the liquid material 31 may be selectively supplied to the bonding film forming region 41 of the first base material 21 by the ink jet method without using the mask as described above. . Thereby, since formation and removal of a mask become unnecessary, the formation process of the liquid film 31 can be simplified.
At this time, the thickness of the bonding film 3 to be formed can be controlled relatively easily by appropriately setting the amount of the liquid material 30 to be supplied to the bonding surface 23.
Here, the liquid material 30 contains a silicone material.

“Silicone material” is a compound having a polyorganosiloxane skeleton, and usually refers to a compound in which the main skeleton (main chain) portion is composed mainly of repeating organosiloxane units, and is a component protruding from a part of the main chain. It may have a branched structure, may be a cyclic body in which the main chain is cyclic, or may be a straight chain in which the ends of the main chain are not connected to each other.
For example, in a compound having a polyorganosiloxane skeleton, the organosiloxane unit has a structural unit represented by the following general formula (1) at the terminal portion and a structural unit represented by the following general formula (2) at the connecting portion. In addition, the branch part has a structural unit represented by the following general formula (3).

［式中、各Ｒは、それぞれ独立して、置換または無置換の炭化水素基を表し、各Ｚは、それぞれ独立して、水酸基または加水分解基を表し、Ｘはシロキサン残基を表し、ａは０または１〜３の整数を表し、ｂは０または１〜２の整数を表し、ｃは０または１を表す。］
なお、シロキサン残基とは、酸素原子を介して隣接する構造単位が有するケイ素原子に結合しており、シロキサン結合を形成している置換基のことを表す。具体的には、−Ｏ−（Ｓｉ）構造（Ｓｉは隣接する構造単位が有するケイ素原子）となっている。

[In the formula, each R independently represents a substituted or unsubstituted hydrocarbon group, each Z independently represents a hydroxyl group or a hydrolyzable group, X represents a siloxane residue, a Represents an integer of 0 or 1 to 3, b represents an integer of 0 or 1 to 2, and c represents 0 or 1. ]
The siloxane residue is a substituent that is bonded to a silicon atom of an adjacent structural unit through an oxygen atom and forms a siloxane bond. Specifically, it has an —O— (Si) structure (Si is a silicon atom of an adjacent structural unit).

  In such a silicone material, the polyorganosiloxane skeleton is branched, that is, the structural unit represented by the general formula (1), the structural unit represented by the general formula (2), and the general formula (3). It is preferable that it is comprised by the structural unit represented by this. The compound having a branched polyorganosiloxane skeleton (hereinafter sometimes abbreviated as “branched compound”) is a compound in which the main skeleton (main chain) portion is mainly composed of repeating organosiloxane units. The repeating of the organosiloxane unit branches in the middle of the main chain, and the ends of the main chain are not connected to each other.

By using this branched compound, in the next step, the bonding film 3 is formed so that the branched chains of this compound contained in the liquid material are entangled with each other. In particular, the film strength is excellent.
In the general formula (1) to the general formula (3), examples of the group R (substituted or unsubstituted hydrocarbon group) include, for example, an alkyl group such as a methyl group, an ethyl group, and a propyl group, a cyclopentyl group, Examples thereof include cycloalkyl groups such as cyclohexyl group, aryl groups such as phenyl group, tolyl group and biphenylyl group, aralkyl groups such as benzyl group and phenylethyl group. Furthermore, some or all of the hydrogen atoms bonded to the carbon atoms of these groups are: I) a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom, II) an epoxy group such as a glycidoxy group, III) Examples include (meth) acryloyl groups such as methacryl groups, IV) groups substituted with anionic groups such as carboxyl groups and sulfonyl groups, and the like.

Hydrolysis groups include alkoxy groups such as methoxy group, ethoxy group, propoxy group and butoxy group, ketoxime groups such as dimethyl ketoxime group and methylethyl ketoxime group, acyloxy groups such as acetoxy group, isopropenyloxy group, isobutenyl Examples include alkenyloxy groups such as oxy groups.
Further, the branched compound preferably has a molecular weight of about 1 × 10 ⁴ to 1 × 10 ^6, more preferably about 1 × 10 ⁵ to 1 × 10 ⁶ . By setting the molecular weight within such a range, the viscosity of the liquid material can be relatively easily set within the above-described range.

  Such branched compounds are preferably those having a silanol group. That is, in the structural units represented by the general formula (1) to the general formula (3), each group Z is preferably a hydroxyl group. Thus, in the next step, when the liquid film 31 is dried to obtain the bonding film 3, the hydroxyl groups of the adjacent branched compounds are bonded to each other, and the obtained bonding film 3 has excellent film strength. It becomes. Furthermore, as described above, when the first base member 21 having a hydroxyl group exposed from the bonding surface (surface) 23 is used, the hydroxyl group included in the branched compound and the first group Since the hydroxyl group of the material 21 is bonded, the branched compound can be bonded to the first substrate 21 not only by physical bonding but also by chemical bonding. As a result, the bonding film 3 is firmly bonded to the bonding surface 23 of the first base material 21.

  Moreover, it is preferable that the hydrocarbon group connected to the silicon atom of the silanol group is a phenyl group. That is, the group R present in the structural unit represented by the general formula (1) to the general formula (3) in which the group Z is a hydroxyl group is preferably a phenyl group. Thereby, since the reactivity of a silanol group improves more, the coupling | bonding of the hydroxyl groups which an adjacent branched compound has comes to be performed more smoothly.

Furthermore, the hydrocarbon group linked to the silicon atom in which no silanol group is present is preferably a methyl group. That is, the group R present in the structural unit represented by the general formula (1) to the general formula (3) in which the group Z does not exist is preferably a methyl group. Thus, a compound in which the group R present in the structural unit represented by the general formula (1) to the general formula (3) in which the group Z does not exist is a methyl group is relatively easily available and inexpensive. In addition, in the subsequent step, by applying bonding energy to the bonding film 3, the methyl group is easily cleaved, and as a result, the bonding film 3 can surely exhibit adhesiveness. It is suitably used as a branch compound (silicone material).
Considering the above, as the branched compound, for example, a compound represented by the following general formula (4) is preferably used.

［式中、ｎは、それぞれ独立して、０または１以上の整数を表す。］
さらに、上述した分枝状化合物は、比較的柔軟性に富む材料である。そのため、後工程において、接合膜３を介して第１の基材２１に第２の基材２２を接合して接合体１を得る際に、例えば、第１の基材２１と第２の基材２２との各構成材料が互いに異なるものを用いる場合であったとしても、各基材２１、２２間に生じる熱膨張に伴う応力を確実に緩和することができる。これにより、最終的に得られる接合体１において、剥離が生じるのを確実に防止することができる。

[Wherein n independently represents an integer of 0 or 1 or more. ]
Furthermore, the above-mentioned branched compound is a material having a relatively high flexibility. Therefore, when the second base material 22 is bonded to the first base material 21 via the bonding film 3 to obtain the joined body 1 in the subsequent process, for example, the first base material 21 and the second base material are used. Even in the case where different constituent materials from the material 22 are used, the stress accompanying thermal expansion generated between the base materials 21 and 22 can be reliably relieved. Thereby, it can prevent reliably that peeling arises in the bonded body 1 finally obtained.

  Moreover, since the branched compound is excellent in chemical resistance, it can be effectively used for joining members that are exposed to chemicals and the like for a long time. Specifically, for example, when manufacturing a droplet discharge head of an industrial inkjet printer that uses an organic ink that easily erodes a resin material, if the bonding film 3 is used for bonding, the durability can be ensured. Can be improved. In addition, since the branched compound is excellent in heat resistance, it can be effectively used for joining members that are exposed to high temperatures.

  Further, the conductive particles 32 are at least near the surface made of a conductive material. Specifically, as such conductive particles 32, for example, the entirety thereof may be composed of a conductive material, and a base particle and a conductive film that covers the surface of the base particle. It may be constituted by. Among these, by setting the conductive particles 32 to the latter configuration, it is easy to adjust the shape, size (average particle diameter, etc.), physical properties (conductivity, density, etc.), etc. of the conductive particles 32.

  Although it does not specifically limit as a constituent material of base material particles, Various metal materials, various ceramic materials, various resin materials, etc. are mentioned. Among these, it is particularly preferable to use a resin material. Since the resin material is generally close to the specific gravity of the silicone material, the conductive particles 32 are unlikely to settle or float in the liquid material 30. That is, the conductive particles 32 that can be uniformly dispersed in the liquid material 30 can be obtained. Further, since the specific gravity of the resin material is relatively small, the conductive particles 32 capable of rapid migration can be obtained.

  In addition, since a material such as a resin material is generally rich in flexibility, particles made of such a flexible material can be easily deformed into a flat shape by applying a compressive force. Therefore, by using flexible particles as the conductive particles 32, the conductive particles 32 are easily flattened between the first base material 21 and the second base material 22, and thus the first conductive pattern 212. In addition, the contact area of the conductive particles 32 with respect to the second conductive pattern 222 can be increased. As a result, in the joined body 1, the conductivity between the conductive patterns 212 and 222 can be further increased. Further, since the conductive particles 32 have flexibility, even when the particle diameter of the conductive particles 32 is non-uniform, the variation in the particle diameter can be compensated for by the deformation of the conductive particles 32. Further, even when the surface of the first conductive pattern 212 and the surface of the second conductive pattern 222 are uneven, the conductive particles 32 are deformed, so that the conductive patterns 212 and 222 and the conductive particles 32 are It can be reliably contacted.

In addition, examples of the constituent material of the conductive film of the conductive particles 32 include the same conductive materials as those of the conductive films 212a and the conductive films 222a described above. In particular, Ni, Cu, or Au is mainly used. A conductive material is preferably used. Since these conductive materials are excellent in conductivity, conductive particles 32 having high conductivity can be obtained, and the conductivity between the conductive patterns 212 and 222 can be increased.
Specific examples of the conductive particles 32 include Ni particles, Ni particles that have been subjected to Au plating, Cu particles that have been subjected to Au plating, resin particles that have been subjected to Au plating, and the like. Can be mentioned.

Further, the particle shape of the conductive particles is not particularly limited, and may be any of spherical shape, flat shape, needle shape, indefinite shape, and the like.
Moreover, it is preferable that the electroconductive particle 32 has elasticity. When the conductive particles 32 having elasticity are compressed, a restoring force for returning to the original shape is generated. This restoring force acts to press the surface of the conductive particles 32 against the conductive patterns 212 and 222 when the conductive particles 32 are compressed between the conductive patterns 212 and 222. For this reason, the contact resistance between the conductive patterns 212 and 222 and the conductive particles 32 can be reduced, and the conductivity between the conductive patterns 212 and 222 can be further increased.

  The average particle diameter of such conductive particles 32 is preferably about 0.5 to 100 μm, and more preferably about 2 to 50 μm. If the average particle diameter of the conductive particles 32 is smaller than the lower limit value, the conductive particles 32 tend to aggregate in the liquid material 30 and it is difficult to uniformly disperse the conductive particles 32. As a result, in the obtained bonding film 3, there is a possibility that the electric resistance in the thickness direction and the surface direction becomes nonuniform. On the other hand, when the average particle diameter of the conductive particles 32 exceeds the upper limit, the probability that the conductive particles 32 are in contact with each other in the liquid coating 31 is increased, and there is a possibility that unintended conductivity is developed in the bonding film 3. is there.

In the present embodiment, the conductive particles 32 are charged. The charged conductive particles 32 migrate in a predetermined direction by the action of an electric field. Thus, by utilizing the electrophoretic phenomenon of the conductive particles 32, the conductive particles 32 can be unevenly distributed in a predetermined region.
The method of charging the conductive particles 32 is not particularly limited, and a corona discharge method, an electrode injection method, a friction method, a method of introducing a functional group on the surface, or the like can be used.

In general, the viscosity (25 ° C.) of the liquid material 30 is preferably about 0.5 to 200 mPa · s, and more preferably about 3 to 20 mPa · s. If the viscosity of the liquid material 30 is within the above range, the liquid material 30 has a certain degree of viscosity, and a thicker liquid coating 31 can be formed. Further, when the liquid film 31 composed of the liquid material 30 is dried in the next step, the liquid material 30 contains a sufficient amount of silicone material and conductive particles 32 to form the bonding film 3. Can be.
On the other hand, when the viscosity of the liquid material 30 exceeds the upper limit, the accuracy of the thickness and shape of the liquid coating 31 may be significantly reduced.

  The liquid material 30 contains the silicone material and the conductive particles 32 as described above, but the silicone material alone is in a liquid state and the conductive particles 32 are dispersed in the liquid material 30. When the viscosity is within the range, a dispersion obtained by dispersing conductive particles 32 in a silicone material can be used as the liquid material 30 as it is. In addition, when the silicone material alone forms a solid or high-viscosity liquid, a solvent or a dispersion medium may be added to the liquid material 30 separately.

Examples of such a solvent or dispersion medium include inorganic solvents such as ammonia, water, hydrogen peroxide, carbon tetrachloride, and ethylene carbonate, ketone solvents such as methyl ethyl ketone (MEK) and acetone, methanol, ethanol, and isopropanol. Alcohol solvents such as butanol, ether solvents such as diethyl ether and diisopropyl ether, cellosolv solvents such as methyl cellosolve, aliphatic hydrocarbon solvents such as hexane and pentane, and aromatic hydrocarbons such as toluene, xylene and benzene Solvents, aromatic heterocyclic compounds such as pyridine, pyrazine, furan, amides such as N, N-dimethylformamide (DMF), halogen compounds such as dichloromethane and chloroform, esters such as ethyl acetate and methyl acetate Solvent, dimethyl sulfoxide (D SO), sulfur compound solvents such as sulfolane, nitrile solvents such as acetonitrile, propionitrile, acrylonitrile, various organic solvents such as organic acid solvents such as formic acid and trifluoroacetic acid, or mixed solvents containing these. Can be used.
Further, the liquid material 30 may contain a dispersant that improves the dispersibility of the conductive particles 32. This dispersant can prevent the conductive particles 32 from aggregating in the liquid material 30.

[3] Next, as shown in FIG. 1C, the first base material 21 and the second base material 22 are overlapped with each other through the liquid film 31. Thereby, the temporary joined body 5 shown in FIG.1 (d) is obtained.
In addition, in the state of this temporary joined body 5, since the 1st base material 21 and the 2nd base material 22 are not joined, a mutual position can be adjusted easily. Therefore, after the first base material 21 and the second base material 22 are once overlapped, the relative positions of these can be finely adjusted, and the dimensional accuracy of the finally obtained joined body can be adjusted. Can be further enhanced.

  [4] Next, as shown in FIG. 2E, a voltage is applied between the first conductive pattern 212 and the second conductive pattern 222. Accordingly, each conductive particle 32 migrates toward either the first conductive pattern 212 or the second conductive pattern 222 in accordance with the polarity of the electric charge that each conductive particle 32 has. As a result, each conductive particle 32 gathers between the first conductive pattern 212 and the second conductive pattern 222, and a sufficient number of conductive particles 32 gather after a certain period of time. As a result, the first conductive pattern 212 and the second conductive pattern 222 are electrically connected via the conductive particles 32.

  In addition, although each conductive particle 32 exists between each conductive film 212a and each conductive film 222a, a region where there is no conductive film, that is, the bonding surface 23 of the first insulating substrate 211 and the second insulation. There are almost no conductive particles 32 between the bonding surface 24 of the conductive substrate 221. Therefore, each conductive film 212a is electrically connected only to the opposing conductive film 222a, and is not electrically connected to the adjacent conductive film 212a or the conductive film 222a not facing. That is, according to the present invention, each conductive film 212a and each conductive film 222a can be selectively electrically connected.

Next, the obtained temporary joined body 5 is compressed in the thickness direction as shown in FIG. Each conductive film 212a and each conductive film 222a shown in FIG. 1 are provided so as to protrude from the surfaces of the respective insulating substrates 211 and 221. Therefore, when the temporary joined body 5 is compressed, the first insulating substrate The distance between 211 and the second insulating substrate is greater than the distance between each conductive film 212a and each conductive film 222a. As a result, the conductive particles 32 make stronger contact with the first conductive pattern 212 and the second conductive pattern 222, and the conductive patterns 212 and 222 can be more reliably connected.
Since the liquid material 30 forming the liquid film 31 has a certain degree of viscosity as described above, the temporary joined body 5 can maintain the compressed state even when the compressive force is released. it can.

Further, in this embodiment, an electric field is generated between the first conductive pattern 212 and the second conductive pattern 222 by applying a voltage between them, whereby the conductive particles 32 are electrically connected. It is running. Thereby, since it is not necessary to separately provide an electrode for generating an electric field, the uneven distribution of the conductive particles 32 can be easily performed.
The electrophoretic conductive particles 32 inevitably gather between the conductive films 212a and the conductive films 222a. For this reason, for example, when electrodes having the same pattern are connected to each other, the electrodes facing each other can be connected and the electrodes not facing each other can be insulated, so that circuit formation can be easily performed.

  In addition, by providing a power source to which a voltage is applied with a function of preventing a short circuit between the first conductive pattern 212 and the second conductive pattern 222, the conductive particles 32 are moved by the electrophoresis. The power supply can detect a short-circuit current generated at the moment when the space between the conductive pattern 212 and the second conductive pattern 222 is filled, so that an accurate timing for stopping the application of voltage can be achieved. Thereby, it is possible to efficiently distribute the conductive particles 32 while preventing useless voltage from being applied.

[5] Next, the liquid film 31 in the temporary joined body 5 is dried (a solvent or a dispersion medium is volatilized). Thereby, the bonding film 3 patterned corresponding to the shape (predetermined shape) of the bonding film formation region 41 is formed.
The bonding film 3 obtained in this manner exhibits adhesiveness by applying energy. When the bonding film 3 has a silanol group as a silicone material, for example, the silanol groups included in the silicone material, and further, the silanol groups and the hydroxyl group included in the first base material 21, Since the bonding film 3 can be reliably bonded, the formed bonding film 3 is excellent in film strength and can be firmly bonded to the first base material 21 and the second base material 22.

In the bonding film 3, the conductive particles 32 are in contact with the conductive films 212a and the conductive films 222a in the thickness direction, but are insulated from each other through a silicone material that is an insulating material in the plane direction. ing. For this reason, the bonding film 3 has conductivity in the thickness direction and has insulation in the surface direction, that is, has so-called anisotropic conductivity.
The temperature at which the liquid material 30 is dried is preferably 25 ° C. or higher, more preferably about 25 to 100 ° C.

Further, the drying time is preferably about 0.5 to 48 hours, more preferably about 15 to 30 hours.
Furthermore, the atmospheric pressure during drying may be under atmospheric pressure, but is preferably under reduced pressure. Specifically, the degree of decompression is preferably about 133.3 × 10 ^{−5 to} 1333 Pa (1 × 10 ^{−5 to} 10 Torr), preferably 133.3 × 10 ^{−4 to} 133.3 Pa (1 × 10 ^{-4 to 1} Torr) is more preferable. Thereby, while drying of the liquid material 30 is accelerated | stimulated, the film | membrane density of the joining film | membrane 3 can be densified, and the joining film | membrane 3 can have the more outstanding film | membrane intensity | strength.
As described above, the film strength and the like of the formed bonding film 3 can be made desired by appropriately setting the conditions for forming the bonding film 3.

  In addition, it is preferable that the content rate of the electroconductive particle 32 in the joining film | membrane 3 is about 1-50 mass%, and it is more preferable that it is about 5-30 mass%. If the content of the conductive particles 32 is less than the lower limit value, it is difficult to fill the gap between each conductive film 212a and each conductive film 222a with the conductive particles 32, and the conductivity between them may be reduced. There is. On the other hand, when the content ratio of the conductive particles 32 exceeds the upper limit, the liquid coating 31 exhibits conductivity even when the conductive particles 32 are not migrated, and the conductive films 212a and the conductive films facing each other. There is a possibility that it is not possible to selectively connect only to 222a. That is, there is a possibility that conductivity is also exhibited in the surface direction of the bonding film 3.

  The average thickness of the bonding film 3 depends on the particle diameter of the conductive particles 32 in the conductive region, but is preferably about 100 nm to 100 μm in the insulating region, and preferably about 200 nm to 10 μm. More preferred. The joining which joined the 1st base material 21 and the 2nd base material 22 by setting the quantity of the liquid material 30 to supply suitably, and setting the average thickness of the joining film 3 formed in the said range. It is possible to bond more firmly while preventing the dimensional accuracy of the body from significantly decreasing.

In addition, when the average thickness of the bonding film 3 is less than the lower limit value, sufficient bonding strength may not be obtained. On the other hand, when the average thickness of the bonding film 3 exceeds the upper limit, the dimensional accuracy of the bonded body 1 may be significantly reduced.
Further, by setting the average thickness of the bonding film 3 in such a range, the second base material 22 brought into contact with the bonding film 3 when the first base material 21 and the second base material 22 are overlapped with each other. Even if particles or the like adhere to the bonding surface 24, the bonding film 3 and the bonding surface 24 can be bonded so as to enclose the particles with the bonding film 3. Therefore, the presence of the particles can accurately suppress or prevent the bonding strength at the interface between the bonding film 3 and the bonding surface 24 from being lowered or the separation at the bonding interface from occurring.

[6] Next, energy is applied to the bonding film 3 in the temporary bonded body 5.
When energy is applied to the bonding film 3, in the bonding film 3, a part of molecular bonds in the vicinity of the front surface and the back surface is cut and the front surface and the back surface are activated. Adhesiveness to the second base material 22 is developed. As a result, the first base material 21 and the second base material 22 can be firmly bonded through the bonding film 3 based on chemical bonding.

  Here, in the present specification, the state in which the front and back surfaces are “activated” means a part of molecular bonds on the front and back surfaces of the bonding film 3 as described above, specifically, for example, polydimethyl In addition to the state in which the methyl group included in the siloxane skeleton is cleaved to generate a bond not terminated in the bonding film 3 (hereinafter also referred to as “unbonded bond” or “dangling bond”). The bonding film 3 is referred to as an “activated” state including a state where the bond is terminated by a hydroxyl group (OH group) and a state where these states are mixed.

  The energy applied to the bonding film 3 may be applied using any method. For example, a method of irradiating the bonding film 3 with an energy beam, a method of heating the bonding film 3, and a compression to the bonding film 3 Examples thereof include a method of applying force (physical energy), a method of exposing the bonding film 3 to plasma (applying plasma energy), a method of exposing the bonding film 3 to ozone gas (applying chemical energy), and the like. Thereby, the front surface and the back surface of the bonding film 3 can be activated efficiently. In addition, since the molecular structure in the bonding film 3 is not cut more than necessary, it is possible to avoid deterioration of the characteristics of the bonding film 3.

Among the above methods, in the present embodiment, as a method for applying energy to the bonding film 3, it is particularly preferable to use a method of irradiating the bonding film 3 with energy rays. Since this method can apply energy to the bonding film 3 relatively easily and efficiently, it is preferably used as a method for applying energy.
Among these, as energy rays, for example, light such as ultraviolet rays and laser light, electromagnetic waves such as X-rays and γ rays, particle beams such as electron beams and ion beams, or two types of these energy rays are used. The combination is mentioned.

  Among these energy rays, it is particularly preferable to use ultraviolet rays having a wavelength of about 126 to 300 nm (see FIG. 2G). With the ultraviolet rays within such a range, the amount of energy applied is optimized, so that the molecular bond forming the skeleton in the bonding film 3 is prevented from being broken more than necessary, and the surface of the bonding film 3 is near the surface. Can be selectively cleaved. As a result, it is possible to reliably cause the bonding film 3 to exhibit adhesiveness while preventing the characteristics (mechanical characteristics, chemical characteristics, etc.) of the bonding film 3 from deteriorating.

In addition, since ultraviolet rays can be processed over a wide range in a short time without unevenness, molecular bonds can be efficiently cut. Furthermore, ultraviolet rays also have the advantage that they can be generated with simple equipment such as UV lamps.
The wavelength of the ultraviolet light is more preferably about 126 to 200 nm.
In the case of using the UV lamp, the output may vary depending on the area of the bonding film 3 is preferably from ^1mW / cm ^{2 ~1W} / cm 2 or ^so, at 5mW / cm ² ~50mW / cm 2 of about More preferably. In this case, the distance between the UV lamp and the bonding film 3 is preferably about 3 to 3000 mm, more preferably about 10 to 1000 mm.

The time for irradiating the ultraviolet rays is such a time that molecular bonds near the surface of the bonding film 3 can be broken, that is, a time that molecular bonds existing near the surface of the bonding film 3 can be selectively broken. It is preferable to do this. Specifically, although it varies slightly depending on the amount of ultraviolet light, the constituent material of the bonding film 3, etc., it is preferably about 1 second to 30 minutes, and more preferably about 1 second to 10 minutes.
Moreover, although an ultraviolet-ray may be irradiated continuously in time, you may irradiate intermittently (pulse form).

  On the other hand, examples of the laser light include a pulsed laser (pulse laser) such as an excimer laser, a continuous wave laser such as a carbon dioxide laser, and a semiconductor laser. Among these, a pulse laser is preferably used. In the pulse laser, heat hardly accumulates with time in the portion of the bonding film 3 irradiated with the laser light, so that the deterioration and deterioration of the bonding film 3 due to the accumulated heat can be reliably prevented. That is, according to the pulse laser, it is possible to prevent the heat accumulated in the bonding film 3 from being affected.

The pulse width of the pulse laser is preferably as short as possible in consideration of the influence of heat. Specifically, the pulse width is preferably 1 ps (picoseconds) or less, and more preferably 500 fs (femtoseconds) or less. If the pulse width is within the above range, the influence of heat generated in the bonding film 3 due to laser light irradiation can be accurately suppressed. A pulse laser having a pulse width as small as the above range is called a “femtosecond laser”.
The wavelength of the laser light is not particularly limited, but is preferably about 200 to 1200 nm, and more preferably about 400 to 1000 nm.

In the case of a pulse laser, the peak output of the laser light varies depending on the pulse width, but is preferably about 0.1 to 10 W, and more preferably about 1 to 5 W.
Furthermore, the repetition frequency of the pulse laser is preferably about 0.1 to 100 kHz, and more preferably about 1 to 10 kHz. By setting the frequency of the pulse laser within the above range, molecular bonds near the surface can be selectively cut.

The various conditions of such laser light are such that the temperature of the portion irradiated with the laser light is preferably from room temperature (room temperature) to about 600 ° C., more preferably about 200 to 600 ° C., and even more preferably 300 to 400 ° C. It is preferable to adjust as appropriate. As a result, it is possible to prevent the temperature of the portion irradiated with the laser light from significantly increasing and selectively break the molecular bond near the surface.
In addition, it is preferable that the laser light applied to the bonding film 3 is scanned along the surface in a state where the focal point is aligned with the surface of the bonding film 3. Thereby, the heat generated by the laser light irradiation is locally accumulated near the surface. As a result, molecular bonds existing on the surface of the bonding film 3 can be selectively desorbed.

  The bonding film 3 may be irradiated with energy rays in any atmosphere. Specifically, the atmosphere, an oxidizing gas atmosphere such as oxygen, a reducing gas atmosphere such as hydrogen, nitrogen, An inert gas atmosphere such as argon, or a reduced pressure (vacuum) atmosphere in which these atmospheres are decompressed may be mentioned. Among them, it is preferable to perform in an air atmosphere (in particular, an atmosphere having a low dew point). Thereby, ozone gas is generated in the vicinity of the surface of the bonding film 3, and the surface is activated more smoothly. Furthermore, it is not necessary to spend time and cost to control the atmosphere, and the irradiation of energy rays can be performed more easily.

As described above, according to the method of irradiating energy rays, it is possible to easily apply energy selectively to the bonding film 3, and therefore, for example, alteration / deterioration of the first base material 21 due to application of energy. Can be prevented.
Moreover, according to the method of irradiating energy rays, the magnitude of energy to be applied can be easily adjusted with high accuracy. For this reason, it is possible to adjust the amount of molecular bonds cut by the bonding film 3. By adjusting the amount of molecular bonds to be cut in this way, the bonding strength between the first base material 21 and the second base material 22 can be easily controlled.

That is, by increasing the amount of molecular bonds that are cleaved near the surface, more active hands are generated near the surface of the bonding film 3, so that the adhesiveness expressed in the bonding film 3 can be further enhanced. On the other hand, by reducing the amount of molecular bonds cleaved in the vicinity of the surface, the number of active hands generated near the surface of the bonding film 3 can be reduced, and the adhesiveness expressed in the bonding film 3 can be suppressed.
In addition, in order to adjust the magnitude | size of the energy to provide, what is necessary is just to adjust conditions, such as the kind of energy beam, the output of an energy beam, the irradiation time of an energy beam.

Furthermore, according to the method of irradiating energy rays, a large amount of energy can be applied in a short time, so that the energy can be applied more efficiently.
As described above, the first base member 21 and the second base member 22 are chemically bonded via the bonding film 3 to obtain the bonded body 1 as shown in FIG.
The bonded body 1 thus obtained is not bonded mainly based on a physical bond such as an anchor effect, but a short time such as a covalent bond, unlike the adhesive used in the conventional bonding method. The two base materials 21 and 22 are bonded to each other based on the strong chemical bond generated in step (b). For this reason, the bonded body 1 can be formed in a short time, is extremely difficult to peel off, and is difficult to cause uneven bonding.

Moreover, according to such a joining method, since the heat processing at high temperature (for example, 180 degreeC or more) is not required, the 1st base material 21 and the 2nd base material 22 which were comprised with the material with low heat resistance. Can also be used for bonding.
In addition, since the first base material 21 and the second base material 22 are bonded via the bonding film 3, there is an advantage that the constituent materials of the base materials 21 and 22 are not limited.
From the above, according to the present invention, the range of selection of each constituent material of the first base material 21 and the second base material 22 can be expanded.

In the bonded body 1, the conductive particles 32 dispersed in the bonding film 3 between the conductive films 212 a constituting the first wiring pattern 212 and the conductive films 222 a constituting the second wiring pattern 222. Is unevenly distributed, so that each conductive film 212a and each conductive film 222a are electrically connected.
In the bonded body 1, the conductive film 212 a and the conductive film 222 a that are not opposed to each other are insulated by the silicone material in the bonding film 3. Further, the adjacent conductive films 212a and the adjacent conductive films 222a are also insulated from each other.
From the above, in the bonded body 1, the conductive region and the insulating region can be easily formed by appropriately adjusting the compression amount of the bonding film 3 (liquid coating 31).

  Further, since the bonding film 3 has a function of insulating the adjacent conductive films 212a and 222a as described above, even when the pitch of the conductive films 212a and 222a is set to be relatively narrow, the conductive film 212a. , 222a can be secured. In addition, since the appropriate film thickness range of the bonding film 3 is relatively thin, the space occupied by the connecting material can be kept extremely small. From these things, it can contribute to the densification of an electric circuit.

In addition, the bonding film 3 is more resistant to organic solvents than an adhesive used for anisotropic conductive films and the like. Therefore, even in the manufacturing process and operation, there is a possibility that the organic solvent contacts the connecting material. It can be used suitably.
Furthermore, since the bonding film 3 can collectively connect the plurality of conductive films 212a and the plurality of conductive films 222a, the time required for the connection process can be shortened.

In addition, the bonding film 3 can increase the conductivity in the thickness direction, and at the same time, increase the thermal conductivity.
Further, the bonding film 3 has an extremely small coefficient of thermal expansion as compared with a conventional adhesive or the like. For this reason, the thickness of the bonding film 3 hardly changes even when the environmental temperature changes. As a result, the bonded body 1 has extremely high dimensional accuracy.

  In this embodiment, since the bonding film 3 is partially formed only in the region to be bonded (bonding film forming region 41), the thermal expansion of the first base material 21 and the second base material 22 is performed. The stress generated at the bonding interface based on the difference in rate is suppressed as compared with the case where the bonding film 3 is formed on the entire bonding surface 23. As a result, peeling of the first base material 21 and the second base material 22 can be reliably suppressed or prevented.

Further, for example, the bonding strength of the bonded body 1 can be easily adjusted by controlling the area and shape of the bonding film forming region 41. As a result, for example, the joined body 1 capable of easily separating the first base material 21 and the second base material 22 is obtained. That is, the bonding strength of the bonded body 1 can be adjusted, and at the same time, the strength (split strength) when separating the bonded body 1 can be adjusted.
From this point of view, when the bonded body 1 that can be easily separated is manufactured, the bonding strength of the bonded body 1 is preferably large enough to be easily separated by a human hand. Thereby, when isolate | separating the conjugate | zygote 1 can be performed easily, without using an apparatus etc.

Further, by controlling the area and shape of the region of the first base material 21 and the second base material 22 that are in contact with the bonding film 3, local concentration of stress generated in the bonding film 3 can be reduced. Thereby, for example, even when the difference in thermal expansion coefficient between the first base material 21 and the second base material 22 is large, the base materials 21 and 22 can be reliably bonded.
Furthermore, according to the bonding method according to the present embodiment, the region where the bonding film 3 is not formed corresponds to the thickness of the bonding film 3 between the first base material 21 and the second base material 22. A space 3c having a distance (height) to be formed is formed. In order to make use of such a space 3c, a closed space or a flow path is formed between the first base material 21 and the second base material 22 by appropriately adjusting the shape of the bonding film forming region 41. can do.
Moreover, when the thermal expansion coefficient of the 1st base material 21 and the thermal expansion coefficient of the 2nd base material 22 are mutually different, it is preferable to join at as low a temperature as possible. By performing the bonding at a low temperature, it is possible to further reduce the thermal stress generated at the bonding interface.

  Specifically, the temperature of the first base material 21 and the second base material 22 is 25 to 50 ° C., depending on the difference in thermal expansion coefficient between the first base material 21 and the second base material 22. It is preferable that the first base material 21 and the second base material 22 are bonded together under the condition of about 25 to 40 ° C., and more preferable. Within such a temperature range, even if the difference in thermal expansion coefficient between the first base material 21 and the second base material 22 is large to some extent, the thermal stress generated at the bonding interface can be sufficiently reduced. . As a result, it is possible to reliably suppress or prevent the occurrence of warpage or peeling in the bonded body 1.

In this case, when the specific difference in thermal expansion coefficient between the first base material 21 and the second base material 22 is 5 × 10 ⁻⁵ / K or more, as described above. Therefore, it is particularly recommended to perform bonding at as low a temperature as possible.
Here, a mechanism for joining the first base material 21 and the second base material 22 in this step will be described.

  For example, the case where a hydroxyl group is exposed on the bonding surface 24 of the second substrate 22 will be described as an example. In this step, the bonding film 3 formed on the first substrate 21 and the second substrate When these are bonded so that the bonding surface 24 of 22 is in contact, the hydroxyl groups present on the surface of the bonding film 3 and the hydroxyl groups present on the bonding surface 24 of the second substrate 22 are bonded by hydrogen bonding. They attract each other and an attractive force is generated between the hydroxyl groups. It is inferred that the first base material 21 and the second base material 22 are joined by this attractive force.

Further, the hydroxyl groups attracting each other by this hydrogen bond are dehydrated and condensed depending on the temperature condition or the like. As a result, at the contact interface between the first base material 21 and the second base material 22, the bonds in which the hydroxyl groups are bonded or the bonds are bonded via oxygen atoms. Thereby, it is guessed that the 1st base material 21 and the 2nd base material 22 are joined more firmly.
Further, bonds that are not terminated on the surface and inside of the bonding film 3 of the first base member 21 and the bonding surface 24 and inside of the second base member 22, that is, unbonded hands (dangling bonds). When the first base material 21 and the second base material 22 are bonded together, these unbonded hands are recombined. Since this recombination occurs in a complicated manner so as to overlap (entangle) with each other, a network-like bond is formed at the bonding interface. Thereby, the bonding film 3 and the second base material 22 are particularly strongly bonded.
As described above, the joined body (joined body of the present invention) 1 shown in FIG. 2 (h) can be obtained.

In addition, the bonded body 1 thus obtained preferably has a bonding strength between the first base material 21 and the second base material 22 of 5 MPa (50 kgf / cm ² ) or more. 100 kgf / cm ² ) or more is more preferable. The bonded body 1 having such bonding strength can sufficiently prevent the peeling. Moreover, according to the joining method of the present invention, it is possible to efficiently produce the joined body 1 in which the first base material 21 and the second base material 22 are joined with the above-described great joint strength.

Further, the volume resistivity in the thickness direction of the bonding film 3 is preferably 1 × 10 ⁵ Ω · cm or less in a region (conductive region) electrically connected through the conductive particles 32. More preferably, it is 1 × 10 ⁴ Ω · cm or less. On the other hand, in the region insulated with the silicone material (insulating region), the volume resistivity in the thickness direction of the bonding film 3 is preferably 1 × 10 ⁸ Ω · cm or more, and preferably 1 × 10 ⁹ Ω. -More preferably, it is cm or more. Similarly, the volume resistivity in the surface direction of the bonding film 3 is preferably 1 × 10 ⁸ Ω · cm or more, and more preferably 1 × 10 ⁹ Ω · cm or more. With the bonding film 3 having such a resistivity, the conductive films 212a and the conductive films 222a are reliably connected to each other, and between the adjacent conductive films 212a and between the adjacent conductive films 222a. Each can be reliably insulated. As a result, it is possible to construct an electric circuit that can reliably prevent loss and short circuit using the joined body 1. Further, according to the bonding method of the present invention, the bonding film 3 that exhibits such excellent anisotropic conductivity can be efficiently produced.
In addition, when obtaining the joined body 1 or after obtaining the joined body 1, at least one of the following two steps ([6A] and [6B]) is performed on the joined body 1 as necessary. One step (step of increasing the bonding strength of the bonded body 1) may be performed. Thereby, the joint strength of the joined body 1 can be further improved easily.

[6A] As shown in FIG. 2 (h), the obtained bonded body 1 is pressurized in a direction in which the first base material 21 and the second base material 22 approach each other.
Thereby, the surface of the bonding film 3 is closer to the surface of the first substrate 21 and the surface of the second substrate 22, respectively, and the bonding strength in the bonded body 1 can be further increased.
Further, by pressurizing the bonded body 1, the gap remaining at the bonded interface in the bonded body 1 can be crushed and the bonded area can be further expanded. Thereby, the joint strength in the joined body 1 can be further increased.

  Further, when the conductive particles 32 have flexibility, the conductive particles 32 are compressed and further flattened, and the contact area between the conductive particles 32 and the respective conductive films 212a and 222a can be further expanded. In addition, since the conductive particles 32 become flatter, a restoring force is generated so that each conductive particle 32 returns to its original shape. Therefore, there is a gap between each conductive particle 32 and each conductive film 212a, 222a. Get closer. As described above, the conductivity between each conductive film 212a and each conductive film 222a can be further increased.

In addition, what is necessary is just to adjust this pressure suitably according to conditions, such as each constituent material of each of the 1st base material 21 and the 2nd base material 22, each thickness, and a joining apparatus. Specifically, it is preferably about 0.2 to 10 MPa, preferably about 1 to 5 MPa, although it varies slightly depending on the constituent materials and thicknesses of the first base material 21 and the second base material 22. It is more preferable that Thereby, the joining strength of the joined body 1 can be reliably increased. In addition, although this pressure may exceed the said upper limit, depending on each component material of the 1st base material 21 and the 2nd base material 22, there exists a possibility that damage etc. may arise in each base material 21 and 22. .
The time for pressurization is not particularly limited, but is preferably about 10 seconds to 30 minutes. In addition, what is necessary is just to change suitably the time to pressurize according to the pressure at the time of pressurizing. Specifically, the higher the pressure at which the bonded body 1 is pressed, the higher the bonding strength can be achieved even if the pressing time is shortened.

[6B] As shown in FIG. 2H, the obtained bonded body 1 is heated.
Thereby, the joint strength in the joined body 1 can be further increased.
At this time, the temperature at the time of heating the bonded body 1 is not particularly limited as long as it is higher than room temperature and lower than the heat resistance temperature of the bonded body 1, but is preferably about 25 to 100 ° C., more preferably 50 to 100 ° C. About ℃. By heating at a temperature in such a range, it is possible to reliably increase the bonding strength while reliably preventing the bonded body 1 from being altered or deteriorated by heat.

The heating time is not particularly limited, but is preferably about 1 to 30 minutes.
Moreover, when performing both said process [6A] and [6B], it is preferable to perform these simultaneously. That is, as shown in FIG. 2 (h), it is preferable to heat the bonded body 1 while pressurizing it. Thereby, the effect by pressurization and the effect by heating are exhibited synergistically, and the joint strength of the joined body 1 can be particularly increased.
By performing the steps as described above, it is possible to easily further improve the bonding strength in the bonded body 1.

<< Second Embodiment >>
Next, a second embodiment of the joining method of the present invention will be described.
3 and 4 are views (longitudinal sectional views) for explaining a second embodiment of the joining method of the present invention. In the following description, the upper side in FIGS. 3 and 4 is referred to as “upper” and the lower side is referred to as “lower”.
Hereinafter, although 2nd Embodiment of the joining method is described, it demonstrates centering around difference with the joining method concerning the said 1st Embodiment, and the description is abbreviate | omitted about the same matter.

In the bonding method according to the present embodiment, a bonding film is formed on each of the first base material 21 and the second base material 22, and the first base material 21 and the second base material are interposed via these bonding films. Except for joining the material 22 and obtaining the joined body 1, it is the same as that of the said 1st Embodiment.
That is, the bonding method according to the present embodiment includes a step of preparing the first base material 21 and the second base material 22, and a bonding film formation region on the first base material 21 (first bonding film formation). The liquid material 30 is supplied to the region 41a) and the bonding film formation region (second bonding film formation region 41b) on the second substrate 22, and the liquid film is applied to each bonding film formation region 41a, 41b. A step of forming 31a and 31b, and a step of superimposing the first base material 21 and the second base material 22 to form a temporary joined body 5 ′ so that the liquid coating 31a and the liquid coating 31b are in close contact with each other. The step of causing the conductive particles 32 to migrate by applying an electric field to each of the liquid coatings 31a and 31b, causing the conductive particles 32 to be unevenly distributed in a predetermined region, and the liquid coatings 31a and 31b in the temporary joined body 5 ′. Are dried to obtain a bonding film 3 ′ and the contact in the temporary bonded body 5 ′. By applying energy to the composite film 3 ′, adhesiveness is developed in the vicinity of the front surface and the back surface of the bonding film 3 ′, and the first base material 21 and the second base material 22 are bonded to each other to join the bonded body 1 ′. And obtaining a process.
Hereinafter, each process of the joining method concerning this embodiment is demonstrated one by one.

  [1] First, in the same manner as in the first embodiment, the first base material 21 including the first insulating substrate 211 and the first wiring pattern 212, the second insulating substrate 212, and the first A second base material 22 composed of two wiring patterns 222 is prepared. In the present embodiment, as shown in FIG. 3A, the first bonding in which the bonding film is formed in a region other than the peripheral portion of one surface (bonding surface 23) of the first base material 21. The film forming region 41a is set, and the region other than the peripheral portion of one surface (bonding surface 24) of the second base material 22 is set as the second bonding film forming region 41b where the bonding film is formed. . Here, the first bonding film formation region 41 a overlaps a part of each conductive film 212 a constituting the first wiring pattern 212, and the second bonding film formation region 41 b includes the second wiring pattern 222. It overlaps with a part of each conductive film 222a which constitutes.

  [2] Next, as shown in FIG. 3B, the liquid material 30 containing the silicone material and the conductive particles 32 is supplied to the first bonding film forming region 41a of the first base member 21. A liquid coating 31a is obtained. Similarly, the liquid material 30 containing the silicone material and the conductive particles 32 is supplied to the second bonding film forming region 41b of the second base material 22 to obtain the liquid coating 31b.

  In this case, the liquid material 30 supplied to the first bonding film formation region 41a and the liquid material 30 supplied to the second bonding film formation region 41b are mutually composed of the silicone material, the degree of polymerization, and the type of conductive particles. Liquid materials having different average particle diameters, contents, etc. may be used, but the same kind of liquid material is preferable. Thereby, the affinity between the liquid coating 31a and the liquid coating 32b is improved. As a result, the liquid coating 31a and the liquid coating 32b can be more easily integrated through the steps described later, so that the first substrate 21 and the second substrate 22 can be bonded more firmly. Can do.

[3] Next, as shown in FIG. 3C, the first base material 21 and the second base material 22 are overlapped so that the liquid coating 31a and the liquid coating 31b are in close contact with each other. Thereby, provisional joined body 5 'shown in Drawing 3 (d) is obtained.
[4] Next, as shown in FIG. 4E, a voltage is applied between the first conductive pattern 212 and the second conductive pattern 222. As a result, an electric field is generated between the first conductive pattern 222 and the second conductive pattern 222, and the conductive particles 32 dispersed in the liquid coating 31a and the liquid coating 31b are transferred to the first conductive pattern 222. As in the first embodiment, the first conductive pattern 212 and the second conductive pattern 222 are gathered.

Next, as necessary, the obtained temporary joined body 5 ′ is compressed in the thickness direction as shown in FIG. As a result, as in the first embodiment, the conductive particles 32 make stronger contact with the first conductive pattern 212 and the second conductive pattern 222, and the conductive patterns 212 and 222 are more reliably connected. Can be conducted.
Further, in the temporary joined body 5 ′ thus compressed, as shown in FIG. 4G, the liquid coating 31a and the liquid coating 31b are integrated.
In this embodiment, since the two liquid coatings 31a and 31b are overlapped, the liquid coating obtained by integrating them spreads outside the bonding film forming regions 41a and 41b. It becomes. Therefore, it is preferable to set the sizes of the bonding film formation regions 41a and 41b in advance in consideration of the spread amount.

[5] Next, the liquid coatings 31a and 31b in the temporary joined body 5 ′ are dried. Thereby, the bonding film 3 ′ is formed.
[6] Next, energy is applied to the bonding film 3 ′ in the temporary bonded body 5 ′ (see FIG. 4G).
When energy is applied to the bonding film 3 ′, a part of molecular bonds in the vicinity of the front surface and the back surface is cut in the bonding film 3 ′, and the surface and the back surface are activated. Adhesiveness to 21 and the second substrate 22 is developed. As a result, the first base material 21 and the second base material 22 can be firmly bonded to each other based on chemical bonding via the bonding film 3 ′.
As described above, the first base material 21 and the second base material 22 are chemically bonded via the bonding film 3 ′, and a bonded body 1 ′ as shown in FIG. 4 (h) is obtained. .

Further, in the bonded body 1 ′, the conductivity dispersed in the bonding film 3 ′ between the respective conductive films 212 a constituting the first wiring pattern 212 and the respective conductive films 222 a constituting the second wiring pattern 222. When the particles 32 are unevenly distributed, the conductive films 212a and the conductive films 222a are electrically connected.
In addition, each conductive film 212a and each conductive film 222a not facing it are insulated by the silicone material in the bonding film 3 ′. Further, the adjacent conductive films 212a and the adjacent conductive films 222a are also insulated from each other.

After obtaining the joined body 1 ′, at least one of the two steps ([6A] and [6B]) in the first embodiment is performed on the joined body 1 ′ as necessary. May be performed. Thereby, it is possible to easily further improve the bonding strength of the bonded body 1 ′ and the conductivity in the thickness direction of the bonding film 3 ′.
In such a second embodiment, the same operation and effect as in the first embodiment can be obtained.
In the present embodiment, the liquid coatings 31a and 31b are formed in the same pattern on both the first base material 21 and the second base material 22, but the pattern of the liquid coatings 31a and 31b. May be different from each other.

<< Third Embodiment >>
Next, a third embodiment of the joining method of the present invention will be described.
5 and 6 are views (longitudinal sectional views) for explaining a third embodiment of the joining method of the present invention. In the following description, the upper side in FIGS. 5 and 6 is referred to as “upper” and the lower side is referred to as “lower”.
Hereinafter, the third embodiment of the bonding method will be described, but the description will focus on differences from the bonding method according to the first embodiment, and description of similar matters will be omitted.

In the bonding method according to the present embodiment, the conductive particles 32 are unevenly distributed by the action of a magnetic field, and then the liquid film 31 is dried to form the bonding film 3. After applying energy to the bonding film 3, the bonding film 3 is formed. The first embodiment is the same as the first embodiment except that the first base material 21 and the second base material 22 are joined together.
That is, in the bonding method according to the present embodiment, the first base material 21 and the second base material 22 are prepared, and the bonding film forming region 41 on the first base material 21 is electrically conductive in the silicone material. The step of supplying the liquid material 30 in which the particles 32 are dispersed to form the liquid coating 31 and applying a magnetic field to the liquid coating 31 causes the electroconductive particles 32 to migrate, thereby causing the electroconductive particles 32 to move into a predetermined region. A step of unevenly distributing, a step of drying the liquid coating 31 to obtain the bonding film 3, a step of developing adhesiveness in the vicinity of the front surface and the back surface of the bonding film 3 by applying energy to the bonding film 3, A step of bonding the first base material 21 and the second base material 22 through the bonding film 3 to obtain a bonded body 1 ″.
Hereinafter, each process of the joining method concerning this embodiment is demonstrated one by one.

[1] First, in the same manner as in the first embodiment, as shown in FIG. 5A, a first base material 21 including a first insulating substrate 211 and a first wiring pattern 212, and A second base material 22 comprising a second insulating substrate 221 and a second wiring pattern 222 is prepared.
[2] Next, as in the first embodiment, as shown in FIG. 5B, the bonding film forming region 41 of the first base material 21 contains the silicone material and the conductive particles 32. The liquid material 30 is supplied, and the liquid film 31 is formed in the bonding film formation region 41.

In the present embodiment, the conductive particles 32 are magnetized. The magnetic conductive particles 32 migrate in a predetermined direction by the action of a magnetic field. By utilizing the magnetophoretic phenomenon of the conductive particles 32 in this manner, the conductive particles 32 can be unevenly distributed in a predetermined region.
Such conductive particles 32 are made of various ferromagnetic materials. Thereby, the electroconductive particle 32 is magnetized by the effect | action of a magnetic field, and becomes a magnet itself. As a result, as will be described in detail later, the plurality of conductive particles 32 can be arranged along the magnetic field, and the arranged plurality of conductive particles 32 can function as a highly conductive wiring.

In addition, as a ferromagnetic material which comprises the electroconductive particle 32, the material containing either Fe, Co, and Ni is used preferably. Since such a ferromagnetic material has high conductivity, the bonding film 3 having high conductivity is finally obtained.
Of the ferromagnetic materials, the hard magnetic material has a large coercive force, so that the conductive particles 32 tend to aggregate together once magnetized. From this point of view, the material constituting the conductive particles 32 is preferably a soft magnetic material among the ferromagnetic materials. Since the conductive particles 32 made of a soft magnetic material have a small coercive force, the agglomeration as described above can be prevented if the magnetic field disappears once it is magnetized. For this reason, even when the magnetic field is applied a plurality of times while finely adjusting the applied position, the conductive particles 32 can be reliably distributed in a predetermined region.

[3] Next, as shown in FIG. 5C, in the first base material 21, the first conductive pattern 212 is used from the lower surface side of the first insulating substrate 211 using the magnetism generating means 6. A magnetic field is selectively generated near each conductive film 212a. As a result, the magnetically conductive particles 32 dispersed in the liquid coating 31 are collected on the first conductive pattern 212 based on the migration phenomenon by the action of the magnetic field.
Further, when the conductive particles 32 are magnetized, the conductive particles 32 are aligned along the direction of the magnetic field. As a result, the conductive particles 32 are aligned in a direction orthogonal to the surface of each conductive film 212a of the first conductive pattern 212.
Examples of the magnetism generating means 6 include a permanent magnet, an electromagnet, and a coil.

[4] Next, the liquid coating 31 is dried (the solvent or the dispersion medium is volatilized). Thereby, the bonding film 3 patterned corresponding to the shape (predetermined shape) of the bonding film formation region 41 is formed.
In the present embodiment, since the liquid coating 31 is dried before the first base material 21 and the second base material 22 are superposed, the subsequent superposition operation can be easily performed. That is, by drying the liquid coating 31, the solid bonding film 3 can be obtained, and the first base material 21 and the second base material 22 can be overlapped via the bonding film 3. In addition, problems such as dripping and adhesion of the liquid coating 31 can be reliably prevented.

[5] Next, as shown in FIG. 6D, energy is applied to the bonding film 3. Thereby, adhesiveness is expressed in the bonding film 3.
[6] Next, as shown in FIG. 6 (e), the first base material 21 and the second base material 22 are bonded together via the bonding film 3. Thereby, a joined body 1 ″ is obtained.
After obtaining the joined body 1 ″, at least one of the two steps ([6A] and [6B]) in the first embodiment is performed on the joined body 1 ″ as necessary. May be performed.
In the third embodiment, the same operation and effect as in the first embodiment can be obtained.
The joining method according to each of the embodiments as described above can be used to join various members.

Examples of members used for such bonding include semiconductor elements such as transistors, diodes, and memories, piezoelectric elements such as crystal oscillators, optical elements such as reflectors, optical lenses, diffraction gratings, and optical filters. , Photoelectric conversion elements such as solar cells, semiconductor substrates and semiconductor elements mounted thereon, insulating substrates and wiring or electrodes, inkjet recording heads, microreactors, microelectromechanical system (MEMS) components such as micromirrors, pressure Sensor parts such as sensors, acceleration sensors, package parts for semiconductor elements and electronic parts, magnetic recording media, magneto-optical recording media, recording media such as optical recording media, liquid crystal display elements, organic EL elements, electrophoretic display elements Such display element parts, fuel cell parts, and the like.
In particular, the bonding method of the present invention capable of high-density mounting should be applied more effectively to mounting various semiconductor devices and electronic components on circuit boards, and to connecting circuit boards to each other and between wirings. Can do.

<Liquid crystal display device>
Here, an embodiment in which the joined body of the present invention is applied to a transmissive liquid crystal display device will be described.
7 is a plan view showing a transmissive liquid crystal display device, FIG. 8 is an exploded perspective view of a liquid crystal panel included in the transmissive liquid crystal display device shown in FIG. 7, and FIG. 9 is a cross-sectional view taken along line AA in FIG. 10 is a cross-sectional view taken along line BB in FIG. In each figure, some members are omitted in order to avoid the figure from becoming complicated. In the following description, the front side of the paper in FIG. 7 is referred to as “up”, the back side of the paper is referred to as “down”, the upper side in FIGS. 8 to 10 is referred to as “up”, and the lower side is referred to as “lower”. .

  A transmissive liquid crystal display device (hereinafter simply referred to as “liquid crystal display device”) 501 shown in each drawing includes a liquid crystal panel (display panel) 502, a plurality of driver IC packages 503 for driving the liquid crystal panel 502, and 2 Two input wiring boards 505 and a backlight (light source means) 506 are provided. The liquid crystal display device 501 can display an image (information) by transmitting light from the backlight 506 to the liquid crystal panel 502.

The liquid crystal panel 502 includes a first base material 507 and a second base material 508 that are arranged to face each other, and between the first base material 507 and the second base material 508, A sealant 509 (see FIG. 9) is provided so as to surround the display area.
Then, in the space defined by the first base material 507, the second base material 508, and the sealing material 509, liquid crystal that is an electro-optical material is accommodated, as shown in FIGS. A liquid crystal layer (intermediate layer) 510 is formed.

The first base material 507 and the second base material 508 are each composed of, for example, various glass materials, various resin materials, and the like.
The first base 507 is provided with a plurality of pixel electrodes 511 arranged in a matrix (matrix) and a signal electrode 512 extending in the X direction on the upper surface (the surface on the liquid crystal layer 510 side). Each column of pixel electrodes 511 is connected to one signal electrode 512 via a switching element 513 such as a TFD element or a TFT element.
In addition, a polarizing plate 514 is provided on the lower surface of the first base material 507.

On the other hand, a plurality of strip-shaped scanning electrodes 515 are provided on the lower surface (the surface on the liquid crystal layer 510 side) of the second substrate 508. These scanning electrodes 515 are arranged to be substantially parallel to each other at a predetermined interval along the Y direction substantially orthogonal to the signal electrode 512 and to be opposed to the pixel electrode 511.
The portion where the pixel electrode 511 and the scanning electrode 515 overlap (including the vicinity thereof) constitutes one pixel, and the liquid crystal of the liquid crystal layer 510 is driven for each pixel between these electrodes, that is, the alignment state of the liquid crystal Changes.

Here, as shown in FIG. 7, the first substrate 507 has an overhang region (frame) 507A that protrudes outward from the outer edge (left side and upper side in FIG. 7) of the second substrate 508 in plan view. is doing.
A wiring pattern 522 that is continuous to the signal electrode 512 and the scanning electrode 515 is formed on the upper surface of the overhang region 507A.

Red (R), green (G), and blue (B) colored layers (color filters) 516 are provided on the lower surface of each scanning electrode 515, and these colored layers 516 are partitioned by a black matrix 517. ing.
A polarizing plate 518 having a polarizing axis different from that of the polarizing plate 514 is provided on the upper surface of the second substrate 508.

  In the liquid crystal panel 502 having such a structure, light emitted from the backlight 506 is polarized by the polarizing plate 514 and then enters the liquid crystal layer 510 through the first substrate 507 and the pixel electrodes 511. Light incident on the liquid crystal layer 510 is intensity-modulated by the liquid crystal whose alignment state is controlled for each pixel. Each light whose intensity is modulated passes through the colored layer 516, the scanning electrode 515, and the second substrate 508, and is then polarized by the polarizing plate 518 and emitted to the outside. Thereby, in the liquid crystal display device 501, from the opposite side to the liquid crystal layer 510 of the second substrate 508, for example, both color image moving images and still images such as letters, numbers, and figures can be visually recognized.

As shown in FIGS. 7 and 9, each driver IC package 503 includes a flexible substrate 520 provided with a drive wiring pattern 519, and is housed in the flexible substrate 520. 519 and a driver IC 521 which is electrically connected.
The driver IC 521 has a function of generating a drive signal to be supplied to the signal electrode 512 and the scan electrode 515, and is composed of a semiconductor chip.
Further, as shown in FIG. 10, the driving wiring pattern 519 is provided in a stripe shape so as to correspond to the wiring pattern 522, and one end portion of each wiring 519 a of the driving wiring pattern 519 is each of the wiring pattern 522. Each wiring 522a is connected (joined).

Each input wiring board 505 is a printed wiring board having an input wiring pattern 523, and receives a signal (image signal or the like) from a circuit board (not shown) on which a power supply IC and a control IC are mounted. Then, the signal is transmitted to each driver IC 521 through the input wiring pattern 523.
Each input wiring pattern 523 is provided so as to correspond to each driving wiring pattern 519, and one end portion of each wiring of the input wiring pattern 523 is connected (bonded) to each wiring 519a of the driving wiring pattern 519, respectively. ) The other end of each wiring of the input wiring pattern 523 is connected to each wiring of the circuit board.

  In the drive system of the liquid crystal display device 501 configured as described above, a signal from the circuit board is input to each driver IC 521 via each input wiring pattern 523 and each driving wiring pattern 519, and each of these driver ICs 521 performs the operation. A drive signal to be supplied to the signal electrode 512 and the scan electrode 515 is generated. A drive signal generated by the driver IC 521 on the signal electrode side (driver IC 521 arranged in parallel along the Y direction in FIG. 7) is supplied to the switching element via the drive wiring pattern 519 and the signal electrode 512. The switching element supplies current to the pixel electrode 511 in accordance with the supplied drive signal. Further, the drive signal generated by the driver IC 521 on the scan electrode 515 side (driver IC 521 arranged in parallel along the X direction in FIG. 7) is supplied to the scan electrode 515 through the drive wiring pattern 519. Thereby, between the pixel electrode 511 and the scanning electrode 515, the liquid crystal of the liquid crystal layer 510 is driven for each pixel, that is, the alignment state of the liquid crystal changes.

In the liquid crystal display device as described above, as shown in FIG. 10, when the overhang region 507A provided with the wiring pattern 522 and the driver IC package 503 provided with the driving wiring pattern 519 are joined, and When the input wiring board 505 and the driver IC package 503 are bonded, the bonding method of the present invention is applied to at least one place.
In other words, the joined body of the present invention is applied to at least one of the joined body of the overhang region 507A and the driver IC package 503 and the joined body of the input wiring board 505 and the driver IC package 503.

  In the present embodiment, as shown in FIG. 10, between the wiring pattern 522 provided in the overhang area 507A and the driving wiring pattern 519 provided in the driver IC package 503, and this driving wiring pattern 519. And the input wiring pattern 523 provided on the input wiring substrate 505 are bonded and electrically connected through the bonding film 3, respectively.

In such a liquid crystal display device 501, even if the pitches of the wiring pattern 522, the driving wiring pattern 519, and the input wiring pattern 523 are set to be relatively narrow, the wiring pattern 522, the driving wiring pattern 519, and the driving The wiring pattern 519 for use and the wiring pattern 523 for input are connected to each other with high conductivity through the bonding film 3 while ensuring the insulation between the adjacent wirings. As a result, the liquid crystal display device 501 can obtain high reliability while achieving downsizing.
As mentioned above, although the joining method and joined body of this invention were demonstrated based on suitable embodiment, this invention is not limited to this.

  For example, in the first embodiment, an electric field is applied to the liquid coating 31 in the temporary bonded body 5. However, before the temporary bonded body 5 is obtained, that is, on the first substrate 21, the liquid coating is applied. After forming 31, an electric field may be applied so that conductive particles 32 are unevenly distributed on each conductive film 212 a. In this case, an electrode or the like for generating an electric field may be prepared separately so that the electric field is selectively generated only in the vicinity of each conductive film 212a.

Further, instead of generating the above-described electric field by applying a voltage between the conductive patterns 212 and 222, a separate electrode may be prepared to generate the electric field.
In the third embodiment, after the liquid coating 31 is formed on the first substrate 21, the magnetic particles are applied to cause the conductive particles 32 to be unevenly distributed on each conductive film 212a. As in the embodiment, after obtaining the temporary joined body 5, a magnetic field may be applied to the liquid coating 31 in the temporary joined body 5.
Moreover, in the joining method of this invention, arbitrary processes can also be added as needed.

Next, specific examples of the present invention will be described.
1. Manufacture of joined body (Example 1)
First, a PET (polyethylene terephthalate) substrate provided with a striped wiring pattern was prepared as a first base material, and a quartz glass substrate provided with a striped wiring pattern was prepared as a second base material. . Each wiring pattern is formed so as to protrude from the substrate surface.
The dimensions of the PET substrate and the quartz glass substrate are each 20 mm long × 20 mm wide × 1 mm average thickness. Each wiring pattern is composed of a copper thin film, the wiring width is 200 μm, and the pitch is 200 μm.

Next, a solution containing a polydimethylsiloxane skeleton as a silicone material and containing toluene and isobutanol as a solvent (manufactured by Shin-Etsu Chemical Co., Ltd., “KR-251”: viscosity (25 ° C.) 18.0 mPa · s ) Was dispersed in a solution so that the content in the finally obtained bonding film was 10% by mass to prepare a liquid material. The conductive particles used were elastic spherical particles having an average particle diameter of 5 μm. In addition, charged particles were used as the conductive particles.
Then, on the PET substrate and the glass substrate, a mask having a window portion having a shape corresponding to the shape of the bonding film forming region (region excluding the frame-like region of the peripheral portion) is provided, and through this mask, A liquid material was supplied by a roll coating method. Thereby, a liquid film was formed so as to cover the wiring patterns of both the substrates.

Next, after removing the mask, the substrates were overlapped so that the liquid coatings were in close contact with each other and the wiring patterns provided on both substrates were facing each other. Thereby, a temporary joined body was obtained.
Next, a DC voltage is applied between the opposing wiring patterns of the obtained temporary joined body. When a direct current voltage was applied, the charged conductive particles in the liquid coating in the temporary joined body were electrophoresed, and a collection of conductive particles was observed between the opposing wiring patterns.
Subsequently, the temporary joined body was compressed at a pressure of 3 MPa in the thickness direction.
Next, the temporary joined body was dried at room temperature (25 ° C.) for 24 hours. Thereby, a bonding film was obtained.
Next, the obtained bonding film was irradiated with ultraviolet rays under the following conditions.

<Ultraviolet irradiation conditions>
-Atmospheric gas composition: Air (air)
・ Atmospheric gas temperature: 20 ℃
・ Atmospheric gas pressure: Atmospheric pressure (100 kPa)
UV wavelength: 172 nm
-Ultraviolet irradiation time: 5 minutes Next, the obtained joined body was heated at 80 ° C while being pressurized at 3 MPa, and maintained for 15 minutes. Thereby, the joint strength of the joined body was improved.

(Example 2)
A joined body was obtained in the same manner as in Example 1 except that the heating temperature for heating the joined body was changed from 80 ° C to 25 ° C.
(Examples 3 to 4)
A joined body was obtained in the same manner as in Example 1 except that the substrate material of the first base material and the substrate material of the second base material were changed to the materials shown in Table 1, respectively.

(Example 5)
A joined body was obtained in the same manner as in Example 1 except that the conductive particles were changed to those having an average particle diameter of 1 μm.
(Example 6)
A bonded body was obtained in the same manner as in Example 1 except that the temporary bonded body was heated at 100 ° C. instead of the method of irradiating the temporary bonded body with ultraviolet rays.
(Example 7)
A joined body was obtained in the same manner as in Example 1 except that copper particles were used as the conductive particles.

(Example 8)
A bonded body was obtained in the same manner as in Example 1 except that the bonding film was not formed on the glass substrate and the bonding film was formed only on the PET substrate.
Example 9
Before superimposing the first base material and the second base material as described below, a magnetic field is applied to the liquid coating to cause the electroconductive particles having magnetism to undergo magnetophoresis, thereby opposing wiring patterns. A joined body was obtained in the same manner as in Example 1 except that the conductive particles were gathered therebetween.
First, the same 1st base material and 2nd base material as Example 1 were prepared. Each wiring pattern is made of a copper thin film, and has a wiring width of 3 mm and a pitch of 3 mm.

Next, in the same solution as in Example 1, nickel particles having a surface plated with gold as conductive particles so that the content in the finally obtained bonded body is 10% by mass. A liquid material was prepared by dispersing. The conductive particles used were spherical particles having an average particle diameter of 5 μm.
Next, a liquid material was supplied onto the surface of the PET substrate in the same manner as in Example 1, thereby forming a liquid film so as to cover the wiring pattern of the PET substrate.

Next, a permanent magnet was disposed at a position corresponding to the wiring pattern on the back surface of the PET substrate. As a result, in accordance with the magnetic field of the permanent magnet, the conductive particles having magnetism migrated and gathered on the wiring pattern.
Next, the liquid film was dried. Thereby, a bonding film was obtained.
Next, the obtained bonding film was irradiated with ultraviolet rays in the same manner as in Example 1. And the 1st base material and the 2nd base material were bonded together so that the bonding film and the surface by the side of the conductive pattern of the 2nd base material may stick. Thereby, the joined body was obtained.
Next, the resulting joined body was heated at 80 ° C. while being pressurized at 3 MPa, and maintained for 15 minutes. Thereby, the joint strength of the joined body was improved.

(Example 10)
A joined body was obtained in the same manner as in Example 9 except that nickel particles were used as the conductive particles. The conductive particles used were magnetic particles having an average particle diameter of 5 μm.
(Comparative Examples 1-3)
The substrate material of the first base material and the substrate material of the second base material are materials shown in Table 1, respectively, and a region similar to the bonding film formation region (region including the conductive pattern) of Example 1 A bonded body was obtained in the same manner as in Example 1 except that the following anisotropic conductive film was adhered.

<Anisotropic conductive film>
Manufacturer: Hitachi Chemical Co., Ltd.
Product name: Anisotropic conductive film "ANISOLM" AC-7000 series Adhesive: Styrene-butadiene-styrene block copolymer (SBS) hot melt Conductive particles: Nickel particles

2. 2. Evaluation of Bonded Body 2.1 Evaluation of Bonding Strength (Split Strength) The bonding strength was measured for each of the bonded bodies obtained in each Example and each Comparative Example.
The measurement of the bonding strength was performed by measuring the strength (load) immediately before peeling off each substrate. Then, the bonding strength was evaluated according to the following criteria.
As a result, the joint strengths of the joined bodies obtained in the respective examples were almost equal to or greater than those of the joined bodies obtained in the respective comparative examples.

2.2 Evaluation of Conductivity of Bonding Film and Conductive Adhesive For the bonding film formed in each Example and the anisotropic conductive film (conductive adhesive) used in Comparative Examples 1 to 3, the thickness direction and surface The electrical resistance in the direction was measured.
Here, in the joined body obtained in each example and each comparative example, the bonding film and the conductive adhesive are measured by measuring the electrical resistance between the conductive patterns connected via the bonding film or the conductive adhesive. The electrical resistance in the thickness direction was measured.
And the resistivity computed based on the measured electrical resistance of the thickness direction of a joining film | membrane and a conductive adhesive was evaluated in accordance with the following evaluation criteria.

<Evaluation criteria for resistivity>
◎: Less than 1 × 10 ² Ω · cm ○: 1 × 10 ² Ω · cm or more, less than 1 × 10 ⁵ Ω · cm Δ: 1 × 10 ⁵ Ω · cm or more, less than 1 × 10 ⁸ Ω · cm ×: 1 × 10 ⁸ Ω · cm or more

2.3 Evaluation of chemical resistance The joined bodies obtained in each of Examples and Comparative Examples were immersed in ink for inkjet printers (manufactured by Epson, “HQ4”) maintained at 80 ° C. for 3 weeks under the following conditions. did. Thereafter, each base material was peeled off, and it was confirmed whether or not ink entered the bonding interface. The results were evaluated according to the following criteria.

<Evaluation criteria for chemical resistance>
◎: Not penetrated at all ○: Slightly penetrated into the corner △: Infiltrated along the edge ×: Intruded inside As described above, each evaluation result of 2.2 to 2.3 Is shown in Table 1.

As is clear from Table 1, the joined bodies obtained in each example had conductivity between the conductive patterns substantially equal to or slightly superior to the joined bodies obtained in each comparative example.
Moreover, the joined body obtained in each Example showed excellent chemical resistance. On the other hand, the joined body obtained in each comparative example was not sufficient in chemical resistance.

It is a figure (longitudinal sectional view) for demonstrating 1st Embodiment of the joining method of this invention. It is a figure (longitudinal sectional view) for demonstrating 1st Embodiment of the joining method of this invention. It is a figure (longitudinal sectional view) for demonstrating 2nd Embodiment of the joining method of this invention. It is a figure (longitudinal sectional view) for demonstrating 2nd Embodiment of the joining method of this invention. It is a figure (longitudinal section) for explaining a 3rd embodiment of the joining method of the present invention. It is a figure (longitudinal section) for explaining a 3rd embodiment of the joining method of the present invention. It is a top view which shows the transmission type liquid crystal display device obtained by applying the conjugate | zygote of this invention. It is a disassembled perspective view of the liquid crystal panel with which the liquid crystal display device shown in FIG. 7 is provided. FIG. 8 is a cross-sectional view taken along line AA in FIG. FIG. 8 is a sectional view taken along line B-B in FIG. 7.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 1 ', 1 "... Assembly 21 ... 1st base material 211 ... 1st insulating board 212 ... 1st wiring pattern 212a ... Conductive film 22 ... 2nd base material 221 2nd insulating substrate 222 ... 2nd wiring pattern 222a ... Conductive film 23, 24 ... Bonding surface 3, 3 '... Bonding film 3c ... Space 30 ... Liquid material 31, 31a, 31b ...... Liquid coating film 41... Bonding film forming area 41 a... First bonding film forming area 41 b... Second bonding film forming area 5, 5 ′ Temporary bonding body 501. Panel 503... Driver IC package 505 .. Input wiring board 506... Backlight 507... First substrate 507 A .. Overhang region 508 ....... Second substrate 509. Layer 511 …… Elementary electrode 512... Signal electrode 513. Switching element 514... Polarizing plate 515 .. Scan electrode 516 .. Colored layer 517... Black matrix 518 ... Polarizing plate 519. Substrate 521 …… Driver IC 522 …… Wiring pattern 523 …… Input wiring pattern

Claims (27)

A first step of preparing a first base material having a first conductive portion on the surface and a second base material having a second conductive portion on the surface as the base material to be bonded via the bonding film; ,
A second step of forming a liquid film by supplying a liquid material containing a silicone material and conductive particles on the surface of at least one of the first substrate and the second substrate;
By applying at least one of an electric field and a magnetic field to the liquid coating, the conductive particles are migrated, and the conductive particles are placed between the first conductive portion and the second conductive portion in the liquid coating. A third step of uneven distribution in the region of
A fourth step of drying the liquid film to obtain the bonding film;
By giving energy to the bonding film, the bonding film is made to exhibit adhesiveness, and a bonded body in which the first base material and the second base material are bonded via the bonding film is obtained. And a fifth step of electrically connecting the first conductive portion and the second conductive portion via the conductive particles in the bonding film.   The bonding method according to claim 1, wherein the silicone material has a main skeleton made of polydimethylsiloxane.   The bonding method according to claim 1, wherein the silicone material has a silanol group.   By applying the energy to the bonding film and expressing the bonding film with adhesiveness, the first base material and the second base material are overlapped with each other through the bonding film. The joining method according to any one of claims 1 to 3, wherein a joined body is obtained.   4. The bonding film according to claim 1, wherein the bonding film is obtained by superimposing the first base material and the second base material on the bonding film and then applying the energy to the bonding film. The joining method according to the above. The conductive particles are charged,
The bonding method according to claim 1, wherein in the third step, the conductive particles are electrophoresed by applying an electric field to the liquid film.   In the third step, by applying a voltage between the first conductive portion and the second conductive portion, the conductive particles are changed into the first conductive portion and the second conductive portion. The bonding method according to claim 6, wherein the bonding method is unevenly distributed between the two.   The bonding method according to claim 1, wherein the conductive particles include base particles and a metal film that covers the surface of the base particles.   The bonding method according to claim 8, wherein the conductive film is composed of Ni, Cu, or Au as a main material.   The joining method according to claim 8 or 9, wherein the base particles are made of a resin material. The conductive particles are made of a ferromagnetic material,
The bonding method according to claim 1, wherein in the third step, the conductive particles are subjected to magnetophoresis by applying a magnetic field to the liquid film.   The bonding method according to claim 11, wherein the ferromagnetic material contains Fe, Co, or Ni.   The joining method according to claim 1, wherein the conductive particles have elasticity.   The joining method according to claim 1, wherein an average particle diameter of the conductive particles is 0.5 to 100 μm.   The bonding method according to claim 1, wherein a content of the conductive particles in the bonding film is 1 to 50% by mass. The first base material is provided as a first insulating substrate and a first conductive portion so as to protrude from a surface located on the bonding film side of the first insulating substrate. And a conductive film of
The second base is provided as a second insulating substrate and a second conductive portion that protrudes from a surface located on the bonding film side of the second insulating substrate. And a conductive film of
The first base material and the second base material are joined through the joint film, and the first conductive film and the second base material are joined through the conductive particles in the joint film. The bonding method according to claim 1, wherein the conductive film is selectively electrically connected to the conductive film.   The bonding according to claim 16, wherein the conductive particles in the bonding film selectively electrically connect regions facing each other in the first conductive film and the second conductive film. Method.   The application of energy in the fifth step is performed by at least one of a method of irradiating the bonding film with energy rays, a method of heating the bonding film, and a method of applying compressive force to the bonding film. The joining method according to claim 1, wherein the joining method is performed.   The bonding method according to claim 18, wherein the energy rays are ultraviolet rays having a wavelength of 126 to 300 nm.   The bonding method according to claim 18, wherein the heating temperature is 25 to 100 ° C.   The joining method according to claim 18, wherein the compressive force is 0.2 to 10 MPa.   The joining method according to any one of claims 1 to 21, wherein the application of the energy in the fifth step is performed in an air atmosphere.   The bonding method according to claim 1, wherein an average thickness of the bonding film is 100 nm to 100 μm. In the second step, the liquid film is formed on the surfaces of both the first base material and the second base material,
The joining method according to any one of claims 1 to 23, wherein in the fifth step, the first base material and the second base material are overlapped so that the liquid coatings are in close contact with each other.   The process according to any one of claims 1 to 24, further comprising, after the fifth step, a process of increasing a bonding strength between the first base material and the second base material on the joined body. The joining method described in 1.   The step of increasing the bonding strength is performed by at least one of a method of irradiating the bonding film with energy rays, a method of heating the bonding film, and a method of applying a compressive force to the bonding film. The bonding method according to claim 25. Each of the first base material and the second base material has a conductive portion on a surface facing each other,
The first base material and the second base material are joined by the joining method according to any one of claims 1 to 26, and the conductive portions are electrically connected. A joined body characterized by comprising.

Images