KR20110049509A - Anisotropic conductive adhesive, method of mounting semiconductor and wafer level package using same - Google Patents

Abstract

The present invention includes a conductive layer comprising an adhesive insulating resin and conductive particles that do not melt at a temperature at which curing of the adhesive insulating resin is completed, and an insulating layer formed on the conductive layer and comprising an adhesive insulating resin. In addition, the conductive layer and the insulating layer selectively relates to an anisotropic conductive adhesive containing a heat-dissipating particles that do not melt at a temperature at which the curing of the adhesive insulating resin is completed, a semiconductor mounting method and a semiconductor level package using the same.

Description

Anisotropic conductive adhesive, method for packaging semiconductors and wafer level package using the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anisotropic conductive adhesive, and more particularly, to an anisotropic conductive adhesive having improved heat dissipation while ensuring sufficient electrical connection between terminals facing each other, a semiconductor mounting method using the same, and a semiconductor level package.

Generally, a conductive adhesive disperse | distributes electroconductive particle, such as a metal, in resin, and is an electrode bonding material which can acquire electroconductivity between opposing electrodes, and can acquire insulation between adjacent electrodes.

In other words, the conductive particles contained in the conductive adhesive enable conduction between the opposite electrodes, while the resin contained in the conductive adhesive ensures insulation between the adjacent electrodes and bonds the opposite electrodes to each other. The substrate is being fixed.

Such conductive adhesives are classified into pastes and films, and are mainly used in electronic components such as semiconductors, for example, flat panel display devices such as LCDs, PDPs, and organic ELs.

However, electronic devices including semiconductors inevitably generate continuous heat, and there is a limit in the ability of the adhesive to transfer heat, which leads to a problem that hot spots occur due to local heat concentration.

The present invention is to solve the above problems, an object of the present invention is to provide an anisotropic conductive adhesive having excellent heat dissipation function is selectively included in the conductive layer and the insulating layer, a semiconductor mounting method and a wafer-level package using the same To provide.

In order to achieve the above object, the present invention is formed on the conductive layer and the conductive layer comprising an adhesive insulating resin and conductive particles that do not melt at a temperature at which curing of the adhesive insulating resin is completed, the adhesive insulating resin It includes an insulating layer comprising a, the conductive layer and the insulating layer optionally comprises heat-dissipating particles that do not melt at a temperature at which curing of the adhesive insulating resin is completed.

In addition, the semiconductor mounting method of the present invention is a semiconductor mounting method for mounting a semiconductor chip having an electrode corresponding to a substrate on which a plurality of substrate electrodes are formed, wherein a conductive adhesive is disposed between the substrate electrode and the semiconductor chip electrode. And heating / pressurizing the conductive adhesive, wherein when the adhesive insulating resin is melted and pressurized, the unmelted conductive particles are inserted between the plurality of semiconductor chip electrodes facing the plurality of substrate electrodes and electrically pressed. Enabling the connection; and curing the adhesive insulating resin to bond the substrate and the semiconductor chip.

In addition, the semiconductor level package of the present invention is configured by dicing a conductive adhesive on the surface of the wafer on which the semiconductor chip is formed.

According to the above configuration, the present invention can secure sufficient electrical connection between terminals such as opposite terminals, and has excellent thermal conductivity during the heating / pressing process by the heat radiating particles, prevents short circuit caused by the conductive particles, and is generated internally. There is an effect that can easily release the heat.

In addition, by blocking the penetration of air or moisture by the heat-dissipating particles can prevent degradation of the performance of the electronic products and extend the life.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description.

 However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms including ordinal numbers such as first and second may be used to describe various components, but the components are not limited by the terms.

The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the second component may be referred to as the first component, and similarly, the first component may also be referred to as the second component.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected or connected to that other component, but it may be understood that other components may be present in between. Should be.

On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

In the present application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

In addition, it is to be understood that the accompanying drawings in this application are shown enlarged or reduced for convenience of description.

Now, the present invention will be described in detail with reference to the accompanying drawings, and the same or corresponding components will be given the same reference numerals regardless of the reference numerals and redundant description thereof will be omitted.

1 is a schematic diagram of an anisotropic conductive adhesive according to an embodiment of the present invention.

Anisotropic conductive adhesive 20 according to an embodiment of the present invention is a conductive layer comprising an adhesive insulating resin 5 and conductive particles 22 that do not melt at a temperature at which curing of the adhesive insulating resin 5 is completed. (23) and an insulating layer (24) formed on the conductive layer (23) and comprising an adhesive insulating resin (5), and adhesive insulating to the conductive layer (23) and the insulating layer (24). Heat dissipation particles 4 which do not melt at a temperature at which curing of the resin 5 is completed are optionally included.

In addition, the conductive layer 23 and the insulating layer 24 may be alternately stacked.

The conductive particles 22 of the conductive layer 23 are, for example, tin (Sn), indium (In), bismuth (Bi), silver (Ag), copper (Cu), zinc (Zn), and lead. (Pb), cadmium (Cd), gallium (Ga), silver (Ag), tarium (Tl) and the like, or an alloy made from these metals.

In addition, the alloy may be Sn-57Bi, Sn-52In, Sn-44In-14Cd or the like having a lower melting point based on Sn-37Pb having a melting point (melting point) of 183 ° C. 2.5Ag-10Sb, Sn-4.7Ag-1.7Cu, Sn-3Cu, Bi-5Sb, In-82Au, Au-12Ge, Sn-80Au, etc. are mentioned.

However, the conductive particles 22 are not necessarily limited thereto, and any conductive material may be used as long as the conductive material does not melt at a temperature at which curing of the adhesive insulating resin 5 is completed.

For example, the metal and the alloy may be mixed and used, and the metal or alloy may be mixed with another metal or alloy.

The heat dissipation particles 4 are selectively included in the conductive layer 23 and the insulating layer 24 to increase the thermal conductivity. The heat dissipation particles 4 may shorten the process time due to rapid heat conduction during heating / pressurization for mounting a semiconductor chip such as a semiconductor, and has an effect of rapidly dissipating heat generated after mounting to the outside.

The heat-dissipating particles (4) has a melting point higher than the heating temperature to withstand heat and pressure during heating / pressurization, preferably a material that does not melt at a temperature at which the curing of the adhesive insulating resin 5 is completed Can be.

In addition, the heat-dissipating particles (4) may be variously selected from several nm to several tens of micrometers according to the size of the conductive particles 22, preferably about 1 / of the average particle diameter of the conductive particles (22) It may be configured within 2 to 1/10, and particularly preferably may be configured to be smaller than the final junction distance between the substrate and the electrode of the semiconductor element.

In addition, the heat-dissipating particles 4 may have a different shape than a spherical shape, and the particles may include spherical particles having different diameters to increase the contact area.

When the heat dissipation particles 4 are properly dispersed in the insulating resin 5, heat passing through the electrode is quickly discharged to the outside by the heat dissipation particles 4. Therefore, excessive temperature rise can be prevented by the generated heat.

On the other hand, it blocks the infiltration of air or moisture and bypasses the infiltration path, reducing the infiltration of air or moisture. As a result, deterioration due to moisture, air, or heat is reduced, thereby preventing performance degradation of electronic products and extending the lifespan.

Hereinafter, the types of the heat dissipating particles 4 may be used as polymer particles such as Teflon and polyethylene, which are non-conductive materials, or silicon-based materials such as alumina, silica, glass, and silicon carbide. It may consist of a mixture and the like.

The non-conductive heat dissipating particles 4 are positioned between the conductive particles 22 to prevent a short circuit caused by the conductive particles 22.

However, when the heat-dissipating particles 4 are included in a volume ratio of 50% or more with respect to the adhesive insulating resin 5, current may be inhibited between the electrode terminals by heat-dissipating particles having non-conductivity, and the adhesive insulating resin When included in a volume ratio of less than 3% with respect to (5) it will not be possible to obtain a sufficient thermal conductivity effect.

Therefore, when the heat dissipation particle 4 is made of a non-conductive material, the heat dissipation particle 4 is preferably included in a volume ratio of 3% to 50% with respect to the adhesive insulating resin (5).

In addition, the heat dissipation particles 4 may be made of a conductive material, and examples of the conductive material include one selected from the group consisting of gold, silver, copper, tungsten, carbon nanotubes (CNT), graphite, and mixtures thereof. The above can be selected.

In this case, even when the conductive particles 22 are constrained between the metal terminals (not shown) to form a conductive path during heating / pressurization for mounting the semiconductor, the heat-dissipating particles 4 may be trapped between the metal terminals. It has conductivity and does not cause a problem of short circuit current between terminals.

In addition, as described above, the heat dissipation particles 4 may be not only composed of a conductive material or a non-conductive material, but may be modified in various forms included in an adhesive to perform a heat dissipation function. For example, the nonconductive material and the conductive material may be alternately formed, or the conductive material or the nonconductive material may be alternately formed in the polymer particles.

Hereinafter, the adhesive insulating resin 5 may be used without limitation as long as the curing of the adhesive insulating resin 5 is completed at a temperature lower than the melting point of the conductive particles 22, but is not limited thereto. It may be at least one selected from the group consisting of a thermoplastic resin, a thermosetting resin and a photocurable resin.

Examples of the thermoplastic resin include vinyl acetate resin, polyvinyl butynal resin, vinyl chloride resin, styrene resin, vinyl methyl ether resin, grevyl resin, ethylene-vinyl acetate copolymer resin, styrene-butadiene copolymer resin, poly Butadiene resin and polyvinyl alcohol resin, and the like, and thermosetting resins include epoxy resins, urethane resins, acrylic resins, silicone resins, phenolic resins, melamine resins, alkyd resins, urea resins and unsaturated polyester resins. Etc. can be used.

Moreover, photocurable resin mixes a photopolymerizable monomer, a photopolymerizable oligomer, a photoinitiator, etc., and has a characteristic that a polymerization reaction is started by light irradiation. Such photopolymerizable monomers and photopolymerizable oligomers include (meth) acrylic acid ester monomers, ether (meth) acrylates, urethane (meth) acrylates, epoxy (meth) acrylates, amino resins (meth) acrylates, and unsaturated poly Ester, silicone resin, etc. can be used.

In addition, the conductive layer 23 and the insulating layer 24 may further include at least one of a flux, a surface active agent, and a curing agent.

In addition, a surface activation resin having a surface activation effect of activating the surface of the conductive particles or the surface of the electrode pad may be used as the adhesive insulating resin. The surface-activated resin has a reducing property for reducing the surface of the conductive particles or the surface of the electrode pad. For example, a resin that heats and liberates an organic acid can be used. By using such a surface activation resin, the surface of the conductive component or the surface of the electrode pad can be activated to improve the conductive component of the electrode pad.

On the other hand, when the thermosetting resin is used, the resin is heated and cured to a temperature where the curing of the resin is completed. When the thermoplastic resin is used, the resin is cooled to the curing temperature of the resin and cured, and the photocurable resin is used. When it does, it irradiates, starts a polymerization reaction, and hardens | cures it.

In particular, in the case of using a thermoplastic resin, it can be expected to have excellent water-retaining properties through reheating in case of fine cracks, breakage and defects of the connection part. On the other hand, the conductive adhesive according to an embodiment of the present invention may further contain a flux, a surface active agent, a curing agent, etc. in the conductive layer and the insulating layer in addition to the main constituent material.

The flux is not particularly limited, and examples thereof include reducing agents such as resins, inorganic acids, amines, and organic acids. Flux is reduced by removing foreign substances such as oxides on the surface of the conductive particles or the upper and lower electrode pads to change into soluble and fusible compounds. In addition, the surface foreign matter is removed to cover the surface of the conductive particles and the upper and lower electrode pads to be cleaned to prevent reoxidation.

The surface active agent is not particularly limited, and examples thereof include glycols such as ethylene glycol and glycerin, organic acids such as maleic acid and azipine acid, amine compounds such as amines, amino acids, organic acid salts of amines, and halogen salts of amines and inorganic acids. With an inorganic acid salt or the like, foreign matter on the surface of the conductive particles or on the surface of the oxide electrode on the opposing upper and lower electrode pad surfaces is dissolved and removed.

Here, it is preferable that the flux or the surfactant has a boiling point lower than the temperature at which curing of the adhesive insulating resin is completed.

Moreover, although a hardening | curing agent is not specifically limited, For example, an indication resin amide, imidazole, etc. can accelerate hardening of an epoxy resin.

2 is a schematic diagram of a semiconductor mounting method according to an embodiment of the present invention.

The plurality of substrate electrodes 25a formed on the substrate 25 and the plurality of semiconductor chip electrodes 26a of the semiconductor chip 26 mounted thereon with the anisotropic conductive adhesive 20 according to the embodiment of the present invention interposed therebetween. Are disposed so as to face each other, and are heated to a predetermined temperature and pressurized so that the distance between the substrate 25 and the semiconductor chip 26 is narrowed.

Through the heating / pressing process, the adhesive insulating resin 5 has a viscosity of several tens to hundreds of cps, so that the unmelted conductive particles 22 freely flow and are constrained between the electrodes 25a and 26a.

Therefore, each of the plurality of semiconductor chip electrodes 26a and the plurality of substrate electrodes 25a opposed thereto electrically connects the two electrodes 25a and 26a opposed by mechanical / physical coupling.

At this time, the heat-dissipating particles 4 has a melting point higher than the temperature at which the adhesive insulating resin 5 is cured as described above, and when the conductive particles 22 are constrained between the electrodes 25a and 26a because they are small in size. It is configured to be separated from the periphery of the electrodes (25a, 26a).

Therefore, the size of the heat dissipation particles 4 is preferably configured to be smaller than the final junction distance between the electrodes (25a, 26a).

In addition, the adhesive insulating resin 5 is cured at a temperature lower than the melting point of the conductive particles 22 and filled between the substrate 25 and the semiconductor chip 26 to insulate the electrical connection. That is, the space other than the electrical junction part which consists of the opposing board | substrate electrode 25a, the semiconductor chip electrode 26a, and the electroconductive particle 22 is insulated.

Thereafter, when the heating temperature is raised to a temperature at which curing of the adhesive insulating resin 5 is completed, the adhesive insulating resin 5 is cured to bond the substrate 25 and the semiconductor chip 26.

The semiconductor mounted in this way has the advantage that the heat dissipation particles 4 having high thermal conductivity are dispersed without interfering with the conductive path, and thus have excellent heat dissipation characteristics.

3 and 4 are conceptual diagrams of a wafer level package according to an embodiment of the present invention.

A wafer level package according to an embodiment of the present invention arranges anisotropic conductive adhesive 500 on a surface of a wafer 400 on which a plurality of semiconductor chips (not shown) are formed, and the wafer 400 It is formed by dicing.

In this case, the anisotropic conductive adhesive 500 may be applied to the surface of the wafer 400 in a paste state and formed to have a uniform thickness by a spin coater or the like, or may be formed on the wafer in a film form.

Here, the anisotropic conductive adhesive 500 includes an adhesive insulating resin 5 and conductive particles 22 and heat dissipating particles 4 which are not cured at a temperature at which the adhesive insulating resin 5 is cured. The conductive particles 22 and the heat-dissipating particles 4 may be dispersed in the adhesive insulating resin 5 without forming.

Hereinafter, the conductive particles 22, the heat dissipating particles 4, and the adhesive insulating resin 5 are the same as described above, and thus detailed descriptions thereof will be omitted.

By such a configuration, there is an advantage in that the semiconductor can be directly mounted by heating / pressurizing without the need for a separate adhesive when mounting the semiconductor.

Preferred embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art having various ordinary knowledge of the present invention may make various modifications, changes, and additions within the spirit and scope of the present invention. And additions should be considered to be within the scope of the following claims.

1 and 2 is a block diagram of a conductive adhesive according to a first embodiment of the present invention.

3 to 5 are conceptual views illustrating a method for mounting a semiconductor according to a first embodiment of the present invention.

6 is a block diagram of a conductive adhesive according to a second embodiment of the present invention.

7 is a conceptual diagram illustrating a method for mounting a semiconductor in accordance with a second embodiment of the present invention.

8 is a configuration diagram of a conductive adhesive according to a third embodiment of the present invention.

9 and 10 are conceptual views illustrating a method of mounting a semiconductor in accordance with a third embodiment of the present invention.

11 and 12 are conceptual views illustrating a method of manufacturing a wafer level package according to an embodiment of the present invention.

Claims (22)

A conductive layer comprising an adhesive insulating resin and conductive particles that do not melt at a temperature at which curing of the adhesive insulating resin is completed; And An insulating layer formed on the conductive layer and comprising an adhesive insulating resin; Anisotropic conductive adhesive optionally containing heat-dissipating particles that do not melt at a temperature at which the curing of the adhesive insulating resin is completed in the conductive layer and the insulating layer. The method of claim 1, The conductive layer and the insulating layer are laminated alternately, characterized in that the anisotropic conductive adhesive. The method of claim 1, The adhesive insulating resin is an anisotropic conductive adhesive, characterized in that at least one selected from the group consisting of a thermoplastic resin, a thermosetting resin and a photoreactive resin. The method of claim 1, The adhesive insulating resin is an anisotropic conductive adhesive, characterized in that it comprises a surface-activated resin. The method of claim 1, The adhesive insulating resin further comprises at least one of a flux, a surface active agent, a curing agent. The method of claim 1, The heat dissipation particles are smaller than the conductive particles, characterized in that the anisotropic conductive adhesive. The method of claim 6, The average diameter of the heat-dissipating particles is an anisotropic conductive adhesive, characterized in that the size is different from 1/10 or more and 1/2 or less of the conductive particle diameter. The method of claim 6, The heat-dissipating particles are anisotropic conductive adhesive, characterized in that at least one selected from the group consisting of conductive gold, silver, copper, tungsten, carbon nanotubes (CNT) and mixtures thereof. The method of claim 6, The heat dissipation particles are anisotropic conductive adhesive, characterized in that consisting of non-conductive particles. The method of claim 6, The heat-dissipating particles are at least one selected from the group consisting of Teflon, polyethylene, alumina, silica, glass and silicon carbide and mixtures thereof, and the like. The method of claim 6, The heat dissipation particles are anisotropic conductive adhesive, characterized in that contained in a volume ratio of 3% to 50% with respect to the adhesive insulating resin. The method of claim 6, The heat dissipation particles are anisotropic conductive adhesive, characterized in that the coating is formed on the resin particles. In the semiconductor mounting method for mounting a semiconductor chip having an electrode corresponding to each of the substrate on which a plurality of substrate electrodes are formed, A conductive layer is formed between the substrate electrode and the semiconductor chip electrode and includes a conductive layer including conductive particles that do not melt at a temperature at which curing of the adhesive insulating resin is completed, and an adhesive insulation. Disposing an anisotropic conductive adhesive comprising an insulating layer comprising a resin, and optionally including heat-dissipating particles which are not melted at a temperature at which curing of the adhesive insulating resin is completed, on the conductive layer and the insulating layer; Heating / pressurizing the conductive adhesive, wherein an unmelted conductive particle is inserted between the plurality of semiconductor chip electrodes facing the plurality of substrate electrodes when an adhesive insulating resin is melted and pressed to enable electrical connection Becoming; And Hardening the adhesive insulating resin to bond the substrate to the semiconductor chip. The method of claim 13, And the size of the heat dissipation particles is smaller than a final bonding distance between the plurality of substrate electrodes and the plurality of semiconductor chip electrodes. The method of claim 13, Wherein said adhesive insulating resin is at least one selected from the group consisting of a thermoplastic resin, a thermosetting resin, and a photoreactive resin. The method of claim 13, And wherein the conductive particles are not melted at a temperature at which curing of the thermosetting resin is completed when the adhesive insulating resin is a thermosetting resin. The method of claim 13, The average diameter of the heat-dissipating particles is a semiconductor mounting method, characterized in that the size is different from 1/10 or more of the diameter of the conductive particles and less than 1/2. The method of claim 13, The heat dissipation particle is a semiconductor mounting method, characterized in that at least one selected from the group consisting of conductive gold, silver, copper, tungsten, carbon nanotubes (CNT) and mixtures thereof. The method of claim 13, The heat dissipation particle is a semiconductor mounting method, characterized in that consisting of non-conductive particles. The method of claim 13, The heat dissipation particle is at least one selected from the group consisting of Teflon, polyethylene, alumina, silica, glass and silicon carbide and mixtures thereof, and the like. The method of claim 13, The heat dissipation particle is a semiconductor mounting method, characterized in that contained in a volume ratio of 3% to 50% with respect to the adhesive insulating resin. A wafer level package comprising the conductive adhesive of claim 1.

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