JP2002141661A - Manufacturing method for multi-layered printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a multi-layered printed wiring board which can obtain the multi-layered printed writing board with superior connection reliability since a through hole can be filled with a resin composition for filling the through hole so that its surface layer becomes flat. SOLUTION: This manufacturing method for the multi-layered printed wiring board includes a through hole forming process for forming the through hole in a substrate which has one layer of a semiconductor circuit and an inter-layer resin insulating layer each formed on both its surfaces, a conductor layer forming process for forming a conductor layer on the wall surface in the through hole and part of the surface of the inter-layer resin insulating layer, a resin filling process for filling the through hole having the conductor layer formed on its wall surface with the resin composition for filling the through hole by using a squeeze, and a through hole forming process for forming a through hole having the resin filler layer formed inside by drying and curing the resin composition for filling the through hole. The angle of the squeeze is set to 3 to 25 deg. in the resin filling process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for manufacturing a multilayer printed wiring board.

[0002]

2. Description of the Related Art In recent years, a so-called build-up multilayer wiring board has attracted attention due to a demand for higher density of the multilayer wiring board. This build-up multilayer wiring board, for example,
It is manufactured by a method as disclosed in Japanese Patent Publication No. 55555/1992. That is, an adhesive for electroless plating made of a photosensitive resin is applied onto the core substrate on which the lower conductive circuit is formed, and then dried and exposed and developed to form an interlayer resin having an opening for a via hole. An insulating layer is formed. Next, after the surface of the interlayer resin insulating layer is roughened by a treatment with an oxidizing agent or the like, the photosensitive resin layer is exposed and developed to provide a plating resist, and then,
A conductive circuit pattern including via holes is formed by applying electroless plating or the like to a portion where the plating resist is not formed. By repeating such a process a plurality of times, a multilayered build-up wiring board is manufactured.

In such a method of manufacturing a build-up wiring board, when a through hole is formed in a core board,
By simply forming a through hole in the core substrate and forming a conductor layer on the wall surface of the through hole, a void is formed in the through hole. If an attempt is made to form an interlayer resin insulation layer with such gaps, when the adhesive for electroless plating is applied, the adhesive for electroless plating flows into the gaps. Depressions (dents) and undulations are generated in the layer made of the plating adhesive. The occurrence of such a concave portion or the like causes a connection failure, and has a problem that the reliability of the build-up wiring board is reduced.

[0004]

Accordingly, as a technique for solving such a problem, there has been proposed a method of filling the space with an epoxy resin paste. Specifically, for example, in Japanese Patent Application Laid-Open No. Hei 10-200265, a multilayer printed wiring board having a through hole filled with a resin filler containing a bisphenol F type epoxy resin and inorganic particles such as silica is disclosed. It has been disclosed.

[0005] When manufacturing a multilayer printed wiring board having no voids in such through holes, the resin filler is filled using a squeegee or the like. As described above, when the resin filler is filled using the squeegee, the shape of the surface layer portion of the filled resin filler may be depressed or raised.

As described above, when the shape of the surface layer portion of the filled resin filler becomes depressed, the resin filler is cured, and when an upper interlayer resin insulating layer is formed, the interlayer resin is removed. There is a problem that a part of the surface of the insulating layer has a concave shape, and the reliability of the obtained multilayer printed wiring board is reduced. Also, when the shape of the surface layer portion of the filled resin filler becomes a raised shape, when the upper interlayer resin insulating layer is further formed, a part of the surface of the interlayer resin insulating layer becomes a raised shape. In order to solve this problem, after filling the resin filler, it is necessary to polish the surface layer of the resin filler to flatten the surface layer of the resin filler.

[0007]

Means for Solving the Problems Accordingly, the present inventors have:
As a result of diligent studies, it has been found that the above problem can be solved by setting the angle of the squeegee to 3 to 25 ° when filling the resin filler using a squeegee in the production of a multilayer printed wiring board. They have found and completed the present invention.

That is, in the method for manufacturing a multilayer printed wiring board according to the present invention, a through-hole forming step of forming a through-hole in a substrate having a conductor circuit and an interlayer resin insulating layer formed on both surfaces thereof is provided. A conductor layer forming step of forming a conductor layer on the wall surface in the hole and a part of the surface of the interlayer resin insulating layer; and a through hole using a squeegee in the through hole in which the conductor layer is formed on the wall surface. A resin filling step of filling the resin composition for filling, and a through hole forming step of drying and curing the resin composition for filling a through hole to form a through hole having a resin filler layer formed therein. A method for manufacturing a multilayer printed wiring board, wherein in the resin filling step, an angle of a squeegee is set to 3 to 25 °.

In the method for producing a multilayer printed wiring board according to the present invention, the resin composition for filling a through hole filled in the resin filling step contains an epoxy resin, a curing agent, and inorganic particles. The content ratio of the inorganic particles is 10 to 5
Desirably, the resin composition is 0% by weight.

It is preferable that the method of manufacturing a multilayer printed wiring board further includes a lid plating layer forming step of forming a lid plating layer covering the through hole after the through hole forming step.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A method of manufacturing a multilayer printed wiring board according to the present invention comprises a through hole forming step of forming a through hole in a substrate having a conductive circuit and an interlayer resin insulating layer formed on both surfaces thereof. A conductor layer forming step of forming a conductor layer on the wall surface in the through hole and a part of the surface of the interlayer resin insulating layer, and in the through hole in which the conductor layer is formed on the wall surface, using a squeegee A resin filling step of filling the resin composition for filling a through hole, and a through hole forming step of drying and curing the resin composition for filling a through hole to form a through hole having a resin filler layer formed therein. Wherein the angle of the squeegee is set to 3 to 25 ° in the resin filling step.

In the method for manufacturing a multilayer printed wiring board according to the present invention, the angle of the squeegee is set to 3 to 25 ° when the resin composition for filling the through hole is filled with the squeegee. Can be completely filled with the resin composition for filling a through-hole, and the resin composition for filling a through-hole can be filled such that the surface layer of the resin composition for filling a through-hole becomes flat. Therefore, after filling the resin composition for filling through-holes, when further forming an upper interlayer resin insulation layer,
The surface of the interlayer resin insulating layer becomes flat, and a multilayer printed wiring board having excellent connection reliability can be manufactured.

Hereinafter, a method for manufacturing a multilayer printed wiring board according to the present invention will be described. The method for manufacturing a multilayer printed wiring board according to the present invention includes the above-described through-hole forming step, conductive layer forming step, resin filling step, and resin filling material layer forming step. Since the method is characterized by setting the angle of the squeegee to 3 to 25 ° when filling the filler, first, these steps will be described with reference to the drawings, and the entire manufacturing of the multilayer printed wiring board will be described. The steps will be described later.

FIG. 1 is a partial cross-sectional view schematically showing one embodiment of a through hole forming step, a conductor layer forming step, a resin filling step, and a through hole forming step in the method for manufacturing a multilayer printed wiring board according to the present invention. . FIG. 1 shows only one surface of the substrate.

In the method for manufacturing a multilayer printed wiring board according to the present invention, in the step of forming a through-hole, conductive circuits 13 are provided on both surfaces thereof.
4 (lower conductive circuit) and the interlayer resin insulating layer 150 are formed in the substrate 101, and a through hole 135 is formed in the substrate 101 (see FIG. 1A). The through-hole 135 can be formed by drilling, laser processing, or the like. In addition, when the material of the substrate has a reinforcing material such as a glass epoxy resin, it is desirable to form the through holes by drilling. The diameter of the through-hole 135 is not particularly limited and may be appropriately selected in consideration of the wiring density of the multilayer printed wiring board.
It is about 400 μm.

When forming a via hole in the interlayer resin insulation layer 150, the via hole opening 15 is formed in advance.
2 is formed in advance. The via hole opening 152 can be formed by laser processing.
When 0 is made of a photosensitive resin, it can also be formed by exposure and development processing.

After the formation of the through hole, the wall surface of the through hole may be subjected to desmear treatment. This is because by performing the desmear treatment, the adhesion to the conductor layer formed in a later step is improved. The desmear treatment can be performed using, for example, an oxidizing agent composed of an aqueous solution such as chromic acid and permanganate. Alternatively, the treatment may be performed by oxygen plasma, mixed plasma of CF ₄ and oxygen, corona discharge, or the like. A method for manufacturing a substrate in which a conductor circuit and an interlayer resin insulating layer are formed on both surfaces thereof will be described later.

After the through hole forming step is completed, the conductor layer forming step is performed. That is, a conductor layer is formed on the wall surface of the through hole 135 and a part of the surface of the interlayer resin insulating layer 150 (FIG. 1).
(B)). In this step, the conductor layer formed on the wall surface of the through-hole 135 forms a through-hole 136, and the conductor layer formed on a part of the surface of the interlayer resin insulating layer 150 corresponds to the upper-layer conductor circuit 145 and the via-hole 146. Becomes In this specification, as necessary, a conductor circuit formed on a substrate is referred to as a lower conductor circuit, and a conductor circuit formed on an interlayer resin insulating layer is referred to as an upper conductor circuit.
The two will be distinguished.

The conductor layer can be formed by, for example, electroless plating. Further, the conductor layer may be formed by a sputtering process instead of the electroless plating process, or both may be used together to form a conductor layer composed of a plurality of layers. Further, a conductor layer including an electroless plating layer and an electrolytic plating layer may be formed by laminating an electrolytic plating layer on the electroless plating layer.

Of these, a conductor layer composed of an electroless plating layer and an electrolytic plating layer is desirable. In particular, a conductor layer constituting an upper conductor circuit desirably has such a configuration for the following reasons. By forming the electroless plating layer in the lower layer, it is possible to form a conductor layer having excellent followability to the surface of the interlayer resin insulating layer, and particularly when a roughened surface is formed on the surface of the interlayer resin insulating layer. Thus, a conductor layer having excellent followability and adhesion to the roughened surface can be formed. Further, when an electrolytic plating layer is formed on this electroless plating layer, the electrolytic plating layer is softer and more malleable than the electroless plating layer, so even if the substrate is warped during a heat cycle. Accordingly, it is possible to follow the dimensional change of the interlayer resin insulating layer. Therefore, by forming a conductor circuit composed of the electroless plating layer and the electrolytic plating layer, a multilayer printed wiring board having excellent connection reliability can be manufactured.

In the case of performing the electroless plating,
A catalyst is applied to a portion to be plated in advance. Examples of the catalyst include palladium and the like.

Among the conductor layers formed in this step, the conductor layer formed on the wall surface of the through hole becomes a through hole,
The conductive layer formed on a part of the surface of the interlayer resin insulating layer is an upper conductive circuit (including via holes), and therefore must be formed in accordance with the wiring pattern. Must. A method for forming a conductor layer according to the wiring pattern on the surface of the interlayer resin insulating layer will be described later.

After forming the conductor layer, it is preferable to form a roughened surface on at least a part of the surface of the conductor layer. This is because the adhesion to the resin filler layer and the interlayer resin insulating layer formed in a later step can be improved. Examples of the method of forming the roughened surface include a blackening (oxidation) -reduction treatment, an etching treatment, and a treatment using a Cu-Ni-P needle-like alloy plating.

As a specific method of the above-mentioned blackening (oxidation) -reduction treatment, NaOH (10 to 20 g / l), NaCl
O ₂ (40 to 50 g / l), Na ₃ PO ₄ (6 to 15 g
/ L), a blackening treatment using an aqueous solution containing (Na) (2.7 to 10 g / l), NaB
A method of performing a reduction treatment using an aqueous solution containing H ₄ (1.0 to 6.0 g / l) as a reduction bath is exemplified.

As the etchant used for the above etching treatment, a mixed solution of an organic acid and a cupric complex is desirable. When a mixed solution of the above organic acid and a cupric complex is used as an etching solution, the reaction between the etching solution and a conductor layer made of copper or the like in the presence of oxygen, that is, the following reaction formulas (1) and (2) The illustrated reaction proceeds, and the conductor layer is etched.

[0026]

Embedded image

The above reaction formulas (1) and (2) are
This is a reaction formula that proceeds when the material of the conductor layer is copper.

The above-mentioned organic acid is added to dissolve copper oxide. Specific examples thereof include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, and the like.
Examples include acrylic acid, crotonic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, maleic acid, benzoic acid, glycolic acid, lactic acid, malic acid, and sulfamic acid.
These may be used alone or in combination of two or more. In the etching solution, the content of the organic acid is desirably 0.1 to 30% by weight. This is because the solubility of the oxidized copper can be maintained and the stability of the catalyst can be ensured. Note that the generated cuprous complex is dissolved by the action of an acid and combines with oxygen to form a cupric complex, which again contributes to copper oxidation. Further, in addition to the above organic acids, inorganic acids such as borofluoric acid, hydrochloric acid and sulfuric acid may be added.

As the cupric complex, a cupric complex of an azole is desirable. This cupric complex of azoles is
It acts as an oxidizing agent that oxidizes metallic copper and the like. Examples of the azoles include diazole, triazole, tetrazole and the like. Among these, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, and 2-undecylimidazole are desirable. In the etching solution, the content of the cupric complex is desirably 1 to 15% by weight. This is because it is excellent in solubility and stability, and can also dissolve noble metals such as Pd constituting the catalyst core.

The etching solution comprising the mixed solution of the organic acid and the cupric complex may contain fluorine ions, chlorine ions, bromine ions, etc. in order to dissolve copper and to assist the oxidizing action of azoles. Good. The halogen ions can be supplied by adding hydrochloric acid, sodium chloride, or the like to the mixed solution. The amount of the supplied halogen ions is preferably 0.01 to 20% by weight. This is because a roughened surface formed by an etching solution containing halogen ions in this range has excellent adhesion to the resin filler layer and the interlayer resin insulating layer. The mixed solution of the organic acid and the cupric complex is prepared by dissolving a cupric complex of an azole, an organic acid and, if necessary, a halogen ion in water.

As the plating treatment, for example, copper sulfate (1 to 40 g / l), nickel sulfate (0.1 to 6.0 g)
/ L), citric acid (10-20 g / l), sodium hypophosphite (10-100 g / l), boric acid (10-40 g / l)
g / l) and a surfactant (Surfynol 465, manufactured by Nissin Chemical Industry Co., Ltd.) (0.01 to 10 g / l).
= 9 in the electroless plating bath, Cu-
A method of forming a roughened layer made of a Ni-P alloy is exemplified. This is because the crystal structure of the plating film deposited in this range has a needle-like structure, and thus has an excellent anchor effect.
A complexing agent or an additive may be added to the electroless plating bath in addition to the compound.

Further, a resin filling step is performed. That is, the resin composition for filling a through-hole is filled using a squeegee into the through-hole 135 having the conductor layer 136 formed on the wall surface thereof (FIG. 1).
(C)). In the method for manufacturing a multilayer printed wiring board of the present invention, the angle of the squeegee is set to 3 to 25 ° when the resin composition for filling through holes is filled in this step.

FIGS. 2A to 2C are partial cross-sectional views for explaining the shape of the resin composition for filling a through-hole when the resin composition for filling a through-hole is filled using a squeegee. By setting the angle of the squeegee to the above range,
As shown in (a), the through-hole is completely filled with the through-hole filling resin composition 153, and the through-hole is formed so that the surface layer portion 153a of the through-hole filling resin composition becomes flat. The filling resin composition can be filled. By filling the through-hole filling resin composition in this manner, an interlayer resin insulating layer having a flat surface and an upper-layer conductor circuit having a desired shape can be laminated thereon, and as a result, the connection reliability is improved. An excellent multilayer printed wiring board can be obtained. Also, in a later step, a flat resin filler layer at the surface layer is formed,
Further, when the lid plating layer is formed, the lid plating layer and the through hole can be reliably connected, and further,
When a via hole is formed on the cover plating layer, both can be reliably connected. In FIG. 2A, 110 is a squeegee, 134 is a lower conductor circuit, 15
0 denotes an interlayer resin insulation layer, 136, 145, and 146 denote conductor layers. In this specification, the angle of the squeegee means the angle between the main surface of the substrate on which the conductor circuit and the interlayer resin insulating layer are formed one by one and the squeegee, and FIG.
, Θ ₁ corresponds to the squeegee angle.

As the squeegee, an elastic body is usually used for the reason described later, so that the angle θ _{2 of} the squeegee is 2
If it exceeds 5 °, a part of the squeegee 210 will enter the through-hole when filling the resin composition for filling the through-hole, and as shown in FIG. The surface portion 253a of the composition has a concave shape. Thus, the surface layer portion 25 of the resin composition for filling through holes is formed.
When 3a has a depressed shape, the surface layer portion of the resin filler layer formed by drying and curing the through-hole filling resin composition 253 in a later step also has a depressed shape.
When an interlayer resin insulation layer or a cover plating layer is formed, a part of the surface of the interlayer resin insulation layer is depressed, the connection between the cover plating layer and the through hole is insufficient, A flat lid plating layer cannot be formed, and a via hole cannot be formed on the lid plating layer. Note that in FIG.
34 is a lower conductor circuit, 250 is an interlayer resin insulation layer, 23
6, 245 and 246 indicate conductor layers.

If the angle θ _{3 of} the squeegee is less than 3 °, it is difficult to suppress the resin composition for filling the through-holes. Therefore, as shown in FIG. The surface portion 353a has a raised shape. As described above, when the surface portion 353a of the resin composition for filling a through hole has a raised shape, the shape of the surface portion of the resin filler layer formed by drying and curing the resin composition 353 for filling a through hole in a later step is formed. When an interlayer resin insulation layer or a cover plating layer is further formed thereon, a part of the surface of the interlayer resin insulation layer is raised, or the cover plating layer and the through-hole are formed. This causes insufficient connection with the aluminum alloy, a lid plating layer having a flat surface cannot be formed, and a via hole cannot be formed on the lid plating layer. In addition,
In FIG. 2C, 310 is a squeegee, 334 is a lower conductor circuit, 350 is an interlayer resin insulation layer, 336 and 345,
346 indicates a conductor layer. Further, when the raised portion of the resin composition for filling the through-hole and the resin filler layer whose surface layer portion has a raised shape is flattened by using a polishing treatment such as belt sander polishing or buff polishing, the above is described above. Although the problem can be solved, the number of manufacturing steps increases, so that the production efficiency decreases. A desirable squeegee angle is 5 to 15 degrees.

The material of the squeegee is not particularly limited. However, since the squeegee has elasticity and has a high ability to follow irregularities of the conductor layer, it is possible to more reliably fill the through hole with the resin composition for filling the through hole. A rubber such as polyethylene is desirable from the viewpoint of being possible, and a rubber having a hardness of 60 ° or more is particularly desirable.
In addition, when it is not particularly necessary to follow the unevenness of the conductor layer, a squeegee made of metal, ceramic, or the like may be used.

The squeegee may have various shapes such as a flat shape and a square shape. In addition, it is possible to improve the filling property of the resin composition for filling through-holes by appropriately making cuts or the like in the squeegee having the above shape. The thickness of the squeegee is not particularly limited, but usually,
10 to 30 mm is desirable, and 15 to 25 mm is more desirable. This is because there is no warping or bending even if printing is repeated.

Examples of the resin composition for filling the through holes to be filled in the resin filling step include those containing epoxy resin, a curing agent such as an imidazole curing agent, and inorganic particles. The epoxy resin is not particularly limited, but is preferably a bisphenol-type epoxy resin or a novolak-type epoxy resin. The viscosity of bisphenol-type epoxy resin can be adjusted without using a diluting solvent by selecting A-type or F-type resin. Novolak-type epoxy resin has high strength, heat resistance and chemical resistance. This is because they are excellent in properties, do not decompose even in a strongly basic solution such as an electroless plating solution, and are hardly thermally decomposed. Further, a bisphenol type epoxy resin and a cresol novolak type epoxy resin may be mixed and used.

Examples of the curing agent include an imidazole-based curing agent, an acid anhydride-based curing agent, and an amine-based curing agent. Examples of the inorganic particles include those made of an aluminum compound, a calcium compound, a potassium compound, a magnesium compound, a silicon compound, and the like. These may be used alone or in combination of two or more.

The shape of the inorganic particles is not particularly limited, and may be spherical, elliptical, crushed, polyhedral, and the like. Among these, a spherical shape and an elliptical spherical shape are desirable. This is because generation of cracks due to the shape of the particles can be suppressed. Further, the inorganic particles may be coated with a silane coupling agent or the like. This is because the adhesion between the inorganic particles and the epoxy resin is improved.

It is desirable that the resin composition for filling the through-holes contains inorganic particles in an amount of 10 to 50% by weight after curing. By including the inorganic particles in the amount in this range, the resin composition for filling through-holes has a viscosity suitable for filling in the through-holes, and a resin filler layer formed through a post-process. The thermal expansion coefficient can be matched between the substrate and the interlayer resin insulating layer.
In addition, the resin filler layer formed using the resin composition for filling through holes containing the inorganic particles in the above range is excellent in metal deposition during electroless plating, and thus is suitable for forming a lid plating layer. ing.

The above-mentioned resin composition for filling through-holes may contain other thermosetting resins, thermoplastic resins and the like in addition to the above-mentioned epoxy resin and the like. Examples of the thermosetting resin include, for example, a polyimide resin and a phenol resin, and examples of the thermoplastic resin include:
Fluororesins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene hexafluoropropylene copolymer (FEP), and tetrafluoroethylene perfluoroalkoxy copolymer (PFA), polyethylene terephthalate (PE)
T), polysulfone (PSF), polyphenylene sulfide (PPS), thermoplastic polyphenylene ether (PPE), polyether sulfone (PES), polyetherimide (PEI), polyphenylene sulfone (PPES), polyethylene naphthalate (PEN) ,
Examples thereof include polyether ether ketone (PEEK) and polyolefin resins. These may be used alone or in combination of two or more. These resins may be used instead of the epoxy resin.

Further, the resin composition for filling a through-hole may include N
MP (normal methylpyrrolidone), DMDG (diethylene glycol dimethyl ether), glycerin, water,
A solvent such as cyclohexanol, cyclohexanone, methylcellosolve, methylcellosolve acetate, methanol, ethanol, butanol, and propanol may be contained, but a solvent containing no solvent is desirable. When the resin composition for filling a through-hole contains a solvent, the solvent has to be removed in a subsequent drying step, but it is difficult to completely remove the solvent, and the resin composition for filling a through-hole has a problem. When the curing treatment is performed with the solvent remaining in the resin, the solvent evaporates due to the heat treatment at the time of curing or the heat treatment in the post-process, and this may cause cracks in the resin filler layer, or the resin filler layer and the interlayer resin. It may cause peeling between the insulating layer and the like.

In this resin filling step, if necessary, a portion other than the inside of the through hole having the conductor layer formed on the wall surface thereof, for example, the upper layer conductor circuit non-formed portion or the via hole is filled with the through hole. It may be filled with a resin composition. By filling the resin composition for filling a through-hole into a portion other than the inside of the through-hole, the entire surface of the substrate on which the upper-layer conductor circuit is formed becomes flat, so that when an interlayer resin insulating layer or the like is further formed by lamination. This is because the surface of the interlayer resin insulating layer can be made flatter.

After performing the above resin filling step, a through hole forming step is further performed. That is, the resin composition 153 for filling the through hole filled in the resin filling step is dried and cured to form a through hole 137 in which the resin filler layer 154 is formed (see FIG. 1D). Specific drying conditions for drying the resin composition for filling a through-hole are not particularly limited, and may be appropriately selected in consideration of the composition of the resin composition for filling a through-hole. ° C
For about 20 to 90 minutes.

The curing conditions of the resin composition for filling the through-hole are not particularly limited, and may be appropriately selected in consideration of the composition of the resin composition for filling the through-hole.
For about 20 to 90 minutes. In addition, the curing treatment performed here may be step curing in which the temperature is gradually changed from a low temperature to a high temperature to perform curing as needed.

After performing the through hole forming step, a lid plating layer forming step of forming a lid plating layer covering the through hole 137 may be performed as necessary. By forming the cover plating layer, a via hole can be formed immediately above the through hole. In the method of manufacturing a multilayer printed wiring board according to the present invention, the surface layer of the resin filler layer formed through the above-described steps is flat, so that the cover plating layer can be suitably formed.
In addition, when the via hole is filled with the resin composition for filling a through hole and dried and cured, a lid plating layer covering the via hole may be formed.

By performing the through hole forming step, the conductor layer forming step, the resin filling step of filling the through hole filling resin composition using a squeegee, and the through hole forming step, the conductive layer is formed on the wall surface thereof. A resin filler layer having a flat surface layer portion can be formed in the through hole in which is formed.

Next, all steps of the method for manufacturing a multilayer printed wiring board according to the present invention will be described in the order of steps. (1) Using an insulating substrate as a starting material, first, a lower conductor circuit is formed on the insulating substrate. As the insulating substrate, for example, a glass epoxy substrate, a polyester substrate,
Examples include a polyimide substrate, a bismaleimide-triazine resin substrate, a copper-clad laminate, and an RCC substrate. Further, the lower layer conductor circuit, for example, after forming a solid conductor layer by electroless plating or the like on the surface of the insulating substrate, forming an etching resist corresponding to the conductor circuit pattern on the conductor layer, , By performing an etching process. After the electroless plating is performed, the thickness of the conductor layer may be increased by performing the electrolytic plating. Further, a copper-clad laminate, an RCC substrate, or the like may be used as a substrate on which a solid conductor layer is formed.

Instead of the above method, for example, the following method may be used. That is, first, a thin conductor layer is formed on the surface of the substrate by electroless plating, sputtering, or the like. Next, a plating resist is formed on a portion of the thin conductor layer where no conductor circuit is formed, and an electroplating layer is formed on the portion where the plating resist is not formed using the thin conductor layer as a plating lead. Further, the lower conductor circuit can be formed on the substrate by peeling off the plating resist and etching away the thin film conductor layer existing under the plating resist.

(2) Next, if necessary, the surface of the lower conductor circuit is subjected to a roughening treatment. As the roughening treatment method, for example, the above-mentioned blackening (oxidation) -reduction treatment, etching treatment, treatment by Cu-Ni-P needle-like alloy plating, or the like can be used.

(3) Next, an uncured resin insulating layer made of a thermosetting resin or a resin composite is formed on the lower conductor circuit, or a resin layer made of a thermoplastic resin is formed.
The uncured resin insulating layer may be formed by applying uncured resin by using a roll coater, a curtain coater, or the like, or may be formed by thermocompression bonding an uncured (semi-cured) resin film. Good. Further, a resin film in which a metal layer such as a copper foil is formed on one surface of an uncured resin film may be attached. The resin layer made of a thermoplastic resin is desirably formed by thermocompression bonding a resin molded body formed into a film.

When the uncured resin is applied, a heat treatment is applied after the application of the resin. By performing the heat treatment, the uncured resin can be thermally cured. The heat curing may be performed after forming a via hole opening and a through hole described later.

When the interlayer resin insulating layer is formed by attaching the above resin film, the interlayer resin insulating layer is formed by pressing the resin film under reduced pressure or vacuum using a device such as a vacuum laminator. Thereafter, the heat treatment is performed by thermosetting the resin film. The heat curing may be performed after forming a via hole opening and a through hole described later.

Also, when the thermoplastic resin formed into a film is bonded by thermocompression bonding to a conductor circuit, the thermoplastic resin formed into a film under reduced pressure or vacuum may be applied using a device such as a vacuum laminator. It is desirable to crimp.

Specific examples of the thermosetting resin include, for example, epoxy resin, phenol resin, polyimide resin,
Examples thereof include a polyester resin, a bismaleimide resin, a polyolefin resin, and a polyphenylene ether resin.

Examples of the epoxy resin include cresol novolak epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolak epoxy resin, alkylphenol novolak epoxy resin, biphenol F epoxy resin, and naphthalene epoxy resin. Resin, dicyclopentadiene type epoxy resin, epoxidized product of condensate of phenols and aromatic aldehyde having phenolic hydroxyl group,
Triglycidyl isocyanurate, alicyclic epoxy resin and the like. These may be used alone or in combination of two or more. Thereby, it becomes excellent in heat resistance and the like.

Examples of the polyolefin resin include polyethylene, polystyrene, polypropylene, polyisobutylene, polybutadiene, polyisoprene, cycloolefin resin, and copolymers of these resins.

Examples of commercially available polyolefin-based resins include, for example, a product name: 15 available from Sumitomo 3M Limited.
92 and the like. Further, a thermoplastic polyolefin resin having a melting point of 200 ° C. or more can be used. Specific commercial products include, for example, trade names: TPX (melting point 240 ° C.) manufactured by Mitsui Petrochemical Industries, Ltd., and Idemitsu Petrochemical Co., Ltd. Trade name: SPS (melting point: 270 ° C.). Among them, cyclo-dielectric materials have low dielectric constant and dielectric loss tangent, are unlikely to cause signal delay and signal error even when a high-frequency signal in the GHz band is used, and are excellent in mechanical characteristics such as rigidity. Olefin resins are desirable.

As the above cycloolefin resin, 2
Homopolymers or copolymers of monomers comprising -norbornene, 5-ethylidene-2-norbornene or derivatives thereof are desirable. As the above derivative, the above 2-
Examples include those in which an amino group for forming a crosslink, a maleic anhydride residue, or a maleic acid-modified one is bonded to a cycloolefin such as norbornene. Examples of monomers for synthesizing the copolymer include ethylene and propylene.

The cycloolefin resin may be a mixture of two or more of the above resins, or may contain a resin other than the cycloolefin resin. When the cycloolefin resin is a copolymer, it may be a block copolymer or a random copolymer.

Further, the cycloolefin resin is preferably a thermosetting cycloolefin resin.
This is because by performing the heating to form the crosslinks, the rigidity is further increased and the mechanical properties are improved. The glass transition temperature (Tg) of the cycloolefin resin is 13
Desirably, the temperature is 0 to 200 ° C.

As the cycloolefin-based resin, those already formed as a resin sheet (film) may be used, and a monomer or a low-molecular-weight polymer having a constant molecular weight may be used as a solvent such as xylene or cyclohexane. It may be in the state of an uncured solution dispersed in. In the case of a resin sheet, a so-called RCC (RESIN COATE
D COPER: resin-coated copper foil). The cycloolefin-based resin may contain a flame retardant such as aluminum hydroxide, magnesium hydroxide, and phosphate ester.

The polyolefin resin may contain an organic filler. By including the organic filler, for example, when a via hole is formed by irradiating the interlayer resin insulating layer with laser light, a via hole opening having a desired shape can be formed well. The organic filler is not particularly restricted but includes, for example, melamine, phenol resin, epoxy resin, polyimide resin, fluororesin, PPO, PPE and the like. These compounds may be used alone or in combination of two or more.

The content of the organic filler is preferably 5 to 60% by weight. The content of the organic filler is 5% by weight
If it is less than 10%, the content of the organic filler is too small, so that the above-mentioned role cannot be fulfilled when irradiating the laser beam, and in some cases, it is not possible to form a via hole opening or the like having a desired shape. is there. On the other hand, if the content of the organic filler exceeds 60% by weight, the characteristics of the polyolefin-based resin are lost, and, for example, the dielectric constant may be excessively high. A more preferable content of the organic filler is 14 to 60% by weight.

The shape of the organic filler is not particularly limited, and may be, for example, a sphere or a polyhedral shape. Among these, cracks are unlikely to occur, and stress is generated in the interlayer resin insulating layer by heat or thermal shock. However, a spherical shape is preferable because the stress is easily alleviated.

The particle size of the organic filler is 0.0
5 to 0.2 μm is preferred. When the particle size of the organic filler is less than 0.05 μm, the particle size is too small, so that it may be difficult to mix the organic filler uniformly, while the particle size of the organic filler is 0.2 μm If the ratio exceeds the above range, the particle size of the organic filler may be too large, so that the organic filler may not be completely decomposed and removed when irradiated with laser light.

When the above-mentioned organic filler is compounded, two or more kinds of organic fillers having different particle diameters may be compounded. However, if too many kinds of organic fillers having different particle diameters are mixed, the organic filler is liable to aggregate. When the size of the agglomerate exceeds 0.2 μm and the same inconvenience as the case where the agglomerate exceeds 0.2 μm is used, there are cases where two types of organic fillers having different diameters are blended. It is desirable to keep the formulation.

Examples of the polyphenylene ether resin include a thermoplastic polyphenylene ether resin having a repeating unit represented by the following chemical formula (3) and a thermosetting polyphenylene ether resin having a repeating unit represented by the following chemical formula (4): And the like.

[0070]

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(In the formula, n represents an integer of 2 or more.)

[0072]

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(In the formula, m represents an integer of 2 or more. R ¹ and R ² represent a methylene group, an ethylene group or a —C
Represents H ₂ —O—CH ₂ —, both of which may be the same or different. The thermoplastic polyphenylene ether resin having a repeating unit represented by the chemical formula (3) has a structure in which a methyl group is bonded to a benzene ring, and is a polyphenylene ether resin that can be used in the present invention. May be a derivative in which the above-mentioned methyl group is substituted with another alkyl group such as an ethyl group, or a derivative in which hydrogen of a methyl group is substituted with fluorine.

Examples of the thermoplastic resin include polyether sulfone and polysulfone. Further, the composite of the thermosetting resin and the thermoplastic resin (resin composite) is not particularly limited as long as it contains a thermosetting resin and a thermoplastic resin, and specific examples thereof include, for example, And a resin composition for forming a roughened surface.

The resin composition for forming a roughened surface includes, for example, an uncured heat-resistant resin matrix which is hardly soluble in a roughening solution comprising at least one selected from acids, alkalis and oxidizing agents. Examples thereof include those in which a substance soluble in a roughening liquid comprising at least one selected from an acid, an alkali, and an oxidizing agent is dispersed. Note that the terms "sparingly soluble" and "soluble" are referred to as "soluble" for convenience when a substance having a relatively high dissolution rate is immersed in the same roughening solution for the same time, and the relative dissolution rate is relatively low. The slower one is called "poorly soluble" for convenience.

The heat-resistant resin matrix is preferably a matrix capable of maintaining the shape of the roughened surface when the roughened surface is formed on the interlayer resin insulating layer using the roughening solution. , Thermoplastic resins, and composites thereof. Alternatively, a photosensitive resin can be used.

The thermosetting resin includes, for example, epoxy resin, phenol resin, polyimide resin, polyolefin resin, fluorine resin and the like. When the thermosetting resin is photosensitized, the thermosetting group is subjected to a (meth) acrylation reaction using methacrylic acid, acrylic acid, or the like. Particularly, a (meth) acrylate of an epoxy resin is desirable. Further, an epoxy resin having two or more epoxy groups in one molecule is more desirable. In addition to being able to form the above-described roughened surface, it is also excellent in heat resistance and the like, so that stress is not concentrated on the conductor circuit even under heat cycle conditions, and the conductor circuit and the interlayer resin insulation layer Peeling hardly occurs between the substrate and the substrate.

Examples of the thermoplastic resin include phenoxy resin, polyether sulfone, polysulfone, polyphenylene sulfone, polyphenylene sulfide, polyphenyl ether, polyether imide and the like. These may be used alone or in combination of two or more.

The substance soluble in the roughening liquid comprising at least one selected from the above-mentioned acids, alkalis and oxidizing agents is selected from inorganic particles, resin particles, metal particles, rubber particles, liquid resin and liquid rubber. It is desirable that it is at least one kind.

The inorganic particles include, for example, aluminum compounds, calcium compounds, potassium compounds, magnesium compounds, silicon compounds and the like. These may be used alone or in combination of two or more.

The aluminum compound includes, for example, alumina and aluminum hydroxide. The calcium compound includes, for example, calcium carbonate,
Calcium hydroxide and the like, as the potassium compound, for example, potassium carbonate and the like, as the magnesium compound, for example, magnesia, dolomite, basic magnesium carbonate, talc and the like,
Examples of the silicon compound include silica and zeolite. These may be used alone or 2
More than one species may be used in combination.

The alumina particles can be dissolved and removed with hydrofluoric acid, and calcium carbonate can be dissolved and removed with hydrochloric acid. Further, sodium-containing silica and dolomite can be dissolved and removed with an alkaline aqueous solution.

Examples of the resin particles include those made of a thermosetting resin, a thermoplastic resin and the like. When immersed in a roughening liquid comprising at least one selected from acids, alkalis and oxidizing agents, There is no particular limitation as long as the dissolution rate is faster than the heat-resistant resin matrix,
Specifically, for example, amino resin (melamine resin, urea resin, guanamine resin, etc.), epoxy resin, phenol resin, phenoxy resin, polyimide resin, polyphenylene resin, polyolefin resin, fluororesin, bismaleimide-triazine resin and the like can be mentioned. . These may be used alone or in combination of two or more.

The epoxy resin can be arbitrarily produced by dissolving in an acid or an oxidizing agent or hardly soluble in the same by selecting the type of oligomer and the curing agent. For example, a resin obtained by curing a bisphenol A-type epoxy resin with an amine-based curing agent is very soluble in chromic acid, but a resin obtained by curing a cresol novolac-type epoxy resin with an imidazole curing agent is not easily dissolved in chromic acid. .

It is necessary that the resin particles have been previously cured. If not cured, the resin particles will dissolve in the solvent that dissolves the resin matrix, so they will be uniformly mixed, and it will not be possible to selectively dissolve and remove only the resin particles with an acid or oxidizing agent. is there.

The metal particles include, for example, gold, silver,
Examples include copper, tin, zinc, stainless steel, aluminum, nickel, iron, lead, and the like. These may be used alone or in combination of two or more. The metal particles may have a surface layer coated with a resin or the like in order to ensure insulation.

Examples of the rubber particles include acrylonitrile-butadiene rubber, polychloroprene rubber, polyisoprene rubber, acrylic rubber, polysulfur-based rigid rubber, fluorine rubber, urethane rubber, silicone rubber, ABS resin and the like.

As the rubber particles, for example, various modified polybutadiene rubbers such as polybutadiene rubber, epoxy-modified, urethane-modified, (meth) acrylonitrile-modified, and (meth) acrylonitrile-butadiene rubber containing a carboxyl group may be used. Can also. By using these rubber particles, the rubber particles are easily dissolved in an acid or an oxidizing agent. In other words, when dissolving the rubber particles using an acid, an acid other than a strong acid can be dissolved, and when dissolving the rubber particles using an oxidizing agent, permanganic acid having a relatively weak oxidizing power can be used. Can be dissolved. Even when chromic acid is used, it can be dissolved at a low concentration. Therefore, no acid or oxidizing agent remains on the surface of the interlayer resin insulating layer, and as described later,
When a catalyst such as palladium chloride is applied after the formation of the roughened surface, no catalyst is applied or the catalyst is not oxidized. These may be used alone or in combination of two or more.

When two or more of the above-mentioned soluble substances are used in combination, the combination of the two soluble substances to be mixed is preferably a combination of resin particles and inorganic particles. Both have low conductivity, so that the insulation of the interlayer resin insulation layer can be ensured, the thermal expansion can be easily adjusted with the poorly soluble resin, and the interlayer resin made of the resin composition for forming a roughened surface can be easily obtained. This is because no crack occurs in the insulating layer, and no peeling occurs between the interlayer resin insulating layer and the conductor circuit.

As the liquid phase resin, an uncured solution of the thermosetting resin can be used. Specific examples of such a liquid phase resin include, for example, an uncured epoxy oligomer and an amine-based curing agent. And the like. Examples of the liquid phase rubber include the above-mentioned polybutadiene rubber, various modified polybutadiene rubbers such as epoxy-modified, urethane-modified and (meth) acrylonitrile-modified, and uncured solutions such as (meth) acrylonitrile-butadiene rubber containing a carboxyl group. Can be used.

When the photosensitive resin composition is prepared using the liquid phase resin or liquid phase rubber, the heat-resistant resin matrix and the soluble substance are not uniformly compatible (that is, the phases are separated). As such, these materials need to be selected. By mixing a heat-resistant resin matrix and a soluble substance selected according to the above criteria, a state in which "islands" of liquid-phase resin or liquid-phase rubber are dispersed in the "sea" of the heat-resistant resin matrix Alternatively, a photosensitive resin composition in which "islands" of a heat-resistant resin matrix are dispersed in a "sea" of a liquid phase resin or a liquid phase rubber can be prepared.

After the photosensitive resin composition in such a state is cured, the roughened surface can be formed by removing the "sea" or "island" liquid phase resin or liquid phase rubber. .

Examples of the acid used as the roughening solution include phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, and organic acids such as formic acid and acetic acid. Of these, it is preferable to use an organic acid. This is because when the roughening treatment is performed, the metal conductor layer exposed from the via hole is hardly corroded. As the oxidizing agent, it is desirable to use, for example, an aqueous solution of chromic acid, chromic sulfuric acid, or an alkaline permanganate (such as potassium permanganate). As the alkali, an aqueous solution of sodium hydroxide, potassium hydroxide or the like is desirable.

The average particle size of the soluble substance is 10 μm
The following is desirable. Further, coarse particles having a relatively large average particle diameter of 2 μm or less and fine particles having a relatively small average particle diameter may be used in combination. That is, a soluble substance having an average particle size of 0.1 to 0.5 μm and an average particle size of 1
Combination with a soluble substance of ２2 μm, and the like.

As described above, the combination of the coarse particles having a relatively large average particle and the fine particles having a relatively small average particle diameter eliminates the dissolution residue of the electroless plating film and reduces the amount of the palladium catalyst under the plating resist. In addition, a shallow and complicated roughened surface can be formed. Further, by forming a complicated roughened surface, a practical peel strength can be maintained even if the unevenness of the roughened surface is small. The coarse particles have an average particle size of more than 0.8 μm and 2.0 μm.
m, the fine particles have an average particle size of 0.1 to 0.8 μm
It is desirable that

By combining the above coarse particles and fine particles, it is possible to form a shallow and complex roughened surface because the coarse particles used when the average particle diameter is less than 2 μm. The anchor formed even when dissolved is removed becomes shallow, and the particles to be removed are formed by the mixture of coarse particles having a relatively large particle diameter and fine particles having a relatively small particle diameter. The roughened surface becomes complicated. By forming such a complicated roughened surface, a practical peel strength can be maintained even with a shallow roughened surface.

In this case, if the particle diameter used is coarse and the average particle diameter is less than 2 μm, roughening does not proceed too much to generate voids, and the formed interlayer resin insulating layer is an interlayer insulating layer. Excellent in nature. In the resin composition for forming an interlayer surface, the particle size of the soluble substance is the length of the longest portion of the soluble substance.

The coarse particles have an average particle diameter of more than 0.8 μm and less than 2.0 μm, and the fine particles have an average particle diameter of 0.1 μm.
When the thickness is approximately 0.8 μm, the depth of the roughened surface is approximately Rmax =
With the semi-additive method, not only the electroless plating film can be easily removed by etching, but also the Pd catalyst under the electroless plating film can be easily removed,
Further, a practical peel strength of 1.0 to 1.3 kg / cm can be maintained.

The shape of the soluble substance is not particularly limited, and examples thereof include a spherical shape and a crushed shape. Further, the shape of the soluble substance is desirably a uniform shape. This is because a roughened surface having unevenness with a uniform roughness can be formed.

The above-mentioned resin composition for forming a roughened surface may contain an organic solvent so that it can be applied on a substrate or the like. (Hereinafter also referred to as a resin film for forming a roughened surface) is desirable. This is because, when forming the interlayer resin insulation layer, if the resin composition for forming a roughened surface is in a liquid state, in a kneading step or a coating step, control items such as temperature and humidity increase, This is because the roughened surface forming resin film is easy to handle. When the above-mentioned resin composition for forming a roughened surface contains an organic solvent, the content is preferably 10% by weight or less.

In the above resin film for forming a roughened surface,
It is desirable that the soluble substance is substantially uniformly dispersed in the heat resistant resin matrix. It is possible to form a roughened surface with unevenness of uniform roughness, and even if via holes and through holes are formed in the resin film, it is possible to secure the adhesion of the metal layer of the conductor circuit formed thereon. Because you can. Further, the above-mentioned resin film for forming a roughened surface may be formed so as to contain a soluble substance only in a surface layer portion forming a roughened surface. Thereby, since the portions other than the surface layer portion of the roughened surface forming resin film are not exposed to the acid or the oxidizing agent, the insulation between the conductor circuits via the interlayer resin insulating layer is reliably maintained.

In the above resin film for forming a roughened surface,
The amount of the soluble substance dispersed in the hardly soluble resin is
The content is preferably 3 to 40% by weight based on the resin film for forming a roughened surface. If the amount of the soluble substance is less than 3% by weight,
In some cases, a roughened surface having desired irregularities cannot be formed. If the amount exceeds 40% by weight, when a soluble substance is dissolved using an acid or an oxidizing agent, the substance is dissolved to a deep portion of the resin film. In addition, the insulation between the conductor circuits via the interlayer resin insulation layer made of the resin film cannot be maintained, which may cause a short circuit.

The above-mentioned resin film for forming a roughened surface desirably contains a curing agent and other components in addition to the above-mentioned soluble substance and the above-mentioned heat-resistant resin matrix. Examples of the curing agent include imidazole-based curing agents, amine-based curing agents, guanidine-based curing agents, epoxy adducts of these curing agents and those obtained by microencapsulating these curing agents, triphenylphosphine, and tetraphenylphosphonate. Organic phosphine-based compounds such as ammonium tetraphenylborate.

The content of the curing agent is desirably 0.05 to 10% by weight based on the resin film for forming a roughened surface. If the content is less than 0.05% by weight, the degree of curing of the roughened surface forming resin film is insufficient, so that the degree of penetration of acid or oxidizing agent into the roughened surface forming resin film increases. The insulation of the film may be impaired. On the other hand, when the content exceeds 10% by weight, an excessive curing agent component may modify the composition of the resin, which may cause a decrease in reliability.

Examples of the other components include fillers such as inorganic compounds and resins which do not affect the formation of the roughened surface. As the inorganic compound, for example,
Examples of the resin include silica, alumina, and dolomite. Examples of the resin include a polyimide resin, a polyacryl resin, a polyamideimide resin, a polyphenylene resin, a melanin resin, and an olefin resin. By incorporating these fillers, the performance of the printed wiring board can be improved by matching the thermal expansion coefficient, improving heat resistance and chemical resistance, and the like.

Further, the resin film for forming a roughened surface is
A solvent may be contained. Examples of the solvent include ketones such as acetone, methyl ethyl ketone and cyclohexanone, ethyl acetate, butyl acetate, and aromatic hydrocarbons such as cellosolve acetate, toluene, and xylene. These may be used alone or in combination of two or more.

The thickness of the interlayer resin insulation layer is not particularly limited, but is preferably 5 to 50 μm. When the thickness is less than 5 μm, insulation between the vertically adjacent conductor circuits may not be maintained. On the other hand, when the thickness is more than 50 μm, when a non-through hole or the like is formed, resin residue may remain on the bottom thereof. It may be generated or the shape of the non-through hole or the like may be tapered toward the bottom.

(4) Next, when an interlayer resin insulating layer using a thermosetting resin or a resin composite as the material is formed, the uncured resin insulating layer is subjected to a hardening treatment and a via hole is formed. An opening is formed to form an interlayer resin insulation layer. The via hole opening is desirably formed by laser processing. The laser processing may be performed before the curing processing or may be performed after the curing processing. In the case where an interlayer resin insulating layer made of a photosensitive resin is formed, an opening for a via hole may be provided by performing exposure and development processes. In this case, the exposure and development processes are performed before the above-described curing process.

When an interlayer resin insulating layer using a thermoplastic resin as the material is formed, a via hole opening is formed in the resin layer made of the thermoplastic resin by laser treatment to form an interlayer resin insulating layer. be able to.

At this time, as a laser to be used, for example, a carbon dioxide laser, an excimer laser, a UV laser,
An AG laser and the like can be mentioned. These lasers may be selectively used in consideration of the shape of a via hole opening or a through hole to be formed.

When forming the via hole opening,
By irradiating laser light with a hologram excimer laser through a mask, a large number of via hole openings can be formed at once. Further, when the via hole opening is formed using a short-pulse carbon dioxide laser, the amount of resin remaining in the opening is small, and the damage to the resin at the periphery of the opening is small.

By irradiating a laser beam through the optical system lens and the mask, a large number of via hole openings can be formed at once. This is because a plurality of portions can be simultaneously irradiated with laser light having the same intensity and the same irradiation angle through the optical lens and the mask.

The through hole formed in the mask is desirably a perfect circle in order to make the spot shape of the laser beam a perfect circle, and the diameter of the through hole is desirably about 0.1 to 2 mm. When the carbon dioxide laser is used, the pulse interval is desirably 10 ⁻⁴ to 10 ⁻⁸ seconds. The time for irradiating the laser for forming the opening is preferably 10 to 500 μsec.

When the opening for the via hole is formed by laser light, and particularly when a carbon dioxide laser is used, desmearing is preferably performed. The desmear treatment can be performed using an oxidizing agent composed of an aqueous solution such as chromic acid and permanganate. In addition, oxygen plasma, CF ₄
It may be treated by a mixed plasma of oxygen and oxygen, corona discharge, or the like. The surface can also be modified by irradiating ultraviolet rays using a low-pressure mercury lamp. The diameter of the via hole opening is not particularly limited, but usually,
40 to 200 μm is desirable.

(5) Next, a roughened surface is formed on the surface of the interlayer resin insulating layer including the inner wall of the via hole opening, if necessary, using an acid or an oxidizing agent. Examples of the acid include sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, and formic acid. Examples of the oxidizing agent include chromic acid, chromic sulfuric acid, and permanganates such as sodium permanganate. Further, the formation of the roughened surface may be performed by using a plasma treatment or the like.

Specifically, when the interlayer resin insulating layer is formed using a resin composition for forming a roughened surface, it is desirable to form the roughened surface using an acid or an oxidizing agent. When formed using a resin or the like, it is desirable to form a roughened surface using a plasma treatment or the like.

The roughened surface is formed in order to enhance the adhesion between the interlayer resin insulating layer and the electroless plating film formed thereon, and the roughened surface is formed between the interlayer resin insulating layer and the electroless plating film. If there is sufficient adhesion between them, it is not necessary to form them.

Thereafter, when the roughened surface is formed using an acid, an aqueous solution of an alkali or the like is used, and when the roughened surface is formed using an oxidizing agent, a neutralizing solution is used to clean the inside of the via hole opening. Neutralize. By this operation, the acid and the oxidizing agent are removed so that the next step is not affected. Such (1) ~
Through the step (5), it is possible to manufacture a substrate in which a conductor circuit and an interlayer resin insulation layer are formed on both surfaces thereof.

(6) Next, the above-described through hole forming step is performed to form a through hole in the substrate. This through-hole forming step is performed after the step (4) is performed, and the step (5) is performed.
When forming the roughened surface in the step, a roughened surface may be simultaneously formed on the wall surface of the through hole.

(7) Next, the above-described conductor layer forming step is performed to form a conductor layer on the wall surface of the through hole and a part of the surface of the interlayer resin insulating layer. Here, as described above,
The formation of the conductor layer forming the through hole and the formation of the conductor layer according to the wiring pattern of the upper conductor circuit (including the via hole) are performed. Therefore, a method of forming a conductor layer according to a wiring pattern will be specifically described.

As described above, when the conductor layer is formed by electroless plating, it is necessary to apply a catalyst such as palladium in advance. Before applying the catalyst, a dry treatment such as a plasma treatment with oxygen or nitrogen or a corona treatment may be performed.
By applying a dry treatment to remove acid or oxidizing agent residues and modifying the surface of the interlayer resin insulation layer, a catalyst is reliably applied, and the metal is deposited during electroless plating, and the electroless plating layer is removed. The adhesion to the interlayer resin insulating layer can be improved, and a great effect can be obtained particularly at the bottom surface of the via hole opening.

First, when a conductor layer (thin film conductor layer) is formed on the wall surface of the through hole by electroless plating or the like, a thin film is simultaneously formed on the entire surface of the interlayer resin insulating layer (including the inner wall surface of the via hole opening). A conductor layer is formed. Next, a plating resist is formed on a portion of the thin film conductor layer where the upper conductor circuit is not formed. The plating resist can be formed, for example, by attaching a photosensitive dry film or the like and performing exposure and development processing.

Next, electroplating is performed using the thin-film conductor layer as a plating lead to form an electroplating layer in the portion where the plating resist is not formed. Further, after forming the electroplating layer, the plating resist is peeled off, and the thin film conductor layer existing under the plating resist is removed by etching. Here, as the etching solution, for example, an aqueous solution of sulfuric acid-hydrogen peroxide, an aqueous solution of persulfate such as ammonium persulfate, sodium persulfate, and potassium persulfate, an aqueous solution of ferric chloride and cupric chloride, hydrochloric acid, nitric acid, and hot water And dilute sulfuric acid.
Further, an etching solution containing a cupric complex and an organic acid can also be used.

By using such a method (first method for forming an upper-layer conductor circuit), an upper-layer conductor circuit can be formed on the interlayer resin insulation layer, and at the same time, the upper and lower layers with the interlayer resin insulation layer interposed therebetween can be formed. Via holes may be formed to electrically connect the conductor circuits. The via hole opening may be filled with electroplating to form a field via structure.After the electroplating, the via hole opening is filled with a conductive paste or the like, and a lid plating layer is formed thereon. A field via structure may be used.

Further, an upper layer conductor circuit can be formed by using the following method (second upper layer conductor circuit formation method) instead of the above first upper layer conductor circuit formation method. That is, first, similarly to the first upper conductor circuit forming method, the thin film conductor layer is formed on the wall surface of the through hole and the entire surface of the interlayer resin insulating layer.

Next, electroplating is performed using the thin-film conductor layer as a plating lead to form an electroplating layer over the entire thin-film conductor layer. Further, an etching resist is formed on the upper conductive circuit forming portion on the electroplating layer. The etching resist can be formed, for example, by attaching a photosensitive dry film or the like and performing exposure and development processing. Further, the electroplating layer and the thin film conductor layer existing under the portion where the etching resist is not formed are removed by etching. Note that the same etchant as that used in the first method for forming the upper conductor circuit can be used. By using such a second method for forming an upper conductor circuit, an upper conductor circuit can be formed on the interlayer resin insulating layer. In the second upper conductor circuit forming method, the field via structure may be formed by filling the via hole opening when performing the electroplating, and the conductive paste may be filled in the via hole opening after the electroplating is completed. Or the like, and a lid plating layer may be formed thereon to form a field via structure.

(8) Next, the above-described resin filling step is performed to fill the through-hole with the resin composition for filling the through-hole. (9) Next, the above-described through-hole forming step is performed to form a through-hole in which a resin filler layer is formed. By forming such a through hole,
The two upper-layer conductor circuits sandwiching the substrate and the interlayer resin insulation layer are electrically connected. Note that, in addition to the two-layer conductor circuits, two-layer lower-layer conductor circuits formed on both sides of the substrate are also connected to the through holes, and a total of four layers of conductor circuits are electrically connected via the through holes. Good. After the formation of the through-hole, a lid plating layer is formed as necessary, as described above.

(10) Next, if necessary, a roughening treatment of the conductor circuit is performed by the same method as described in the above (2), and then the steps (3) to (9) are repeated. A substrate in which a conductor circuit and an interlayer resin insulation are sequentially laminated can be manufactured. When the steps (3) to (9) are repeated, a through-hole may or may not be formed.

(11) Next, a solder resist layer is formed on the surface of the substrate including the uppermost conductive circuit, a solder pad is formed by opening the solder resist layer, and a solder paste is applied to the solder pad. Filling and reflowing form solder bumps. Then, pins are arranged on the connection surface of the external board, or solder balls are formed, so that a PGA (Pin Grid Array) or a BGA (Ball Grid Array) is formed.
Array).

The above-mentioned solder resist layer can be formed by using, for example, a solder resist composition composed of polyphenylene ether resin, polyolefin resin, fluororesin, thermoplastic elastomer, epoxy resin, polyimide resin and the like. Specific examples include, for example, the same resins as those used for the interlayer resin insulating layer.

Examples of the solder resist composition other than those described above include, for example, a novolak-type epoxy resin (meth) acrylate, an imidazole curing agent, a bifunctional (meth) acrylate monomer, and a molecular weight of 500 to 50.
A paste-like fluid containing a polymer of about 00 (meth) acrylate, a thermosetting resin such as a bisphenol-type epoxy resin, a photosensitive monomer such as a polyvalent acrylic monomer, a glycol ether-based solvent, and the like. It is desirable that the viscosity is adjusted to 1 to 10 Pa · s at 25 ° C. Examples of the (meth) acrylate of the novolak epoxy resin include an epoxy resin obtained by reacting glycidyl ether of phenol novolak or cresol novolak with acrylic acid, methacrylic acid, or the like.

The bifunctional (meth) acrylic acid ester monomer is not particularly restricted but includes, for example, acrylic acid and methacrylic acid esters of various diols, and commercially available products thereof are manufactured by Nippon Kayaku Co., Ltd. R-604,
PM2, PM21 and the like.

The above solder resist composition may contain an elastomer or an inorganic filler. When the elastomer is blended, the formed solder resist layer absorbs or relieves the stress even when stress is applied to the solder resist layer due to the flexibility and rebound resilience of the elastomer. As a result, it is possible to suppress the occurrence of cracks and peeling in the solder resist layer after the electronic component such as an IC chip is mounted on the manufacturing process of the multilayer printed wiring board or the manufactured multilayer printed wiring board. Even when cracks occur, the crack cannot grow large.

The method of opening the solder resist layer includes, for example, a method of irradiating a laser beam in the same manner as the method of forming a via hole opening.

When a photosensitive solder resist composition is used as the solder resist composition, after a solder resist layer is formed, a photoresist is placed on the solder resist layer and exposed and developed. By applying, the solder resist layer can be opened.

The conductor circuit portion exposed by opening the solder resist layer is usually desirably covered with a corrosion-resistant metal such as nickel, palladium, gold, silver, and platinum. Specifically, nickel-gold, nickel-
It is desirable to form the coating layer with a metal such as silver, nickel-palladium, nickel-palladium-gold, and the like. The coating layer can be formed by, for example, plating, vapor deposition, electrodeposition, and the like, and among these, plating is preferable because of excellent uniformity of the coating layer.

In addition, a plasma treatment with oxygen, carbon tetrachloride, or the like may be performed as needed for a character printing process for forming product recognition characters or the like or for modifying a solder resist layer.

[0138]

The present invention will be described in more detail below. Example 1 A. Preparation of Resin Film for Interlayer Resin Insulation Layer Bisphenol A type epoxy resin (Epoxy equivalent 46
9. Yuka Shell Epoxy Epicoat 1001) 30
Parts by weight, 40 parts by weight of a cresol novolak type epoxy resin (epoxy equivalent: 215, Epicron N-673 manufactured by Dainippon Ink and Chemicals, Inc.) Light KA-705
2) 30 parts by weight were dissolved by heating in 20 parts by weight of ethyl diglycol acetate and 20 parts by weight of solvent naphtha while stirring, and epoxidized polybutadiene rubber (Denalex R-45EPT manufactured by Nagase Kasei Kogyo Co., Ltd.) was added thereto.
15 parts by weight, 1.5 parts by weight of a crushed product of 2-phenyl-4,5-bis (hydroxymethyl) imidazole, 2 parts by weight of finely divided silica, and 0.5 part by weight of a silicon-based antifoaming agent are added, and an epoxy resin composition is added. Was prepared. The resulting epoxy resin composition is applied on a 38 μm-thick PET film using a roll coater so that the thickness after drying becomes 50 μm, and then dried at 80 to 120 ° C. for 10 minutes to form an interlayer resin. A resin film for an insulating layer was produced.

B. Preparation of Resin Composition for Filling Through Holes 100 parts by weight of a bisphenol F type epoxy monomer (manufactured by Yuka Shell Co., Ltd., molecular weight: 310, YL983U), the average particle size of which surface is coated with a silane coupling agent is 1.6 μm, S whose maximum particle diameter is 15 μm or less
iO ₂ spherical particles (CRS 1101- manufactured by Adtech Co., Ltd.)
CE) 72 parts by weight and 1.5 parts by weight of a leveling agent (Perenol S4 manufactured by San Nopco Co.) are placed in a container, and the mixture is stirred and mixed to have a viscosity of 30 to 60 at 23 ± 1 ° C.
A Pa · s resin filler was prepared. In addition, as a curing agent, an imidazole curing agent (2E4MZ- manufactured by Shikoku Chemicals Co., Ltd.)
6.5 parts by weight (CN).

C. Production of multilayer printed wiring board (1) Glass epoxy resin or BT with a thickness of 0.8 mm
A starting material was a copper-clad laminate in which an 18 μm copper foil 32 was laminated on both sides of an insulating substrate 30 made of (bismaleimide triazine) resin (see FIG. 3A). First, the copper-clad laminate was etched into a lower conductor circuit pattern to form lower conductor circuits 34 on both surfaces of the substrate (see FIG. 3B).

(2) Substrate 3 on which lower conductor circuit 34 is formed
After washing with water and drying, NaOH (10 g / l),
NaClO ₂ (40 g / l), Na ₃ PO ₄ (6 g / l)
a blackening treatment using an aqueous solution containing l) as a blackening bath (oxidizing bath);
And NaOH (10 g / l), NaBH ₄ (6 g / l
3), a roughening surface 34a was formed on the surface of the lower conductor circuit 34 (FIG. 3).
(C)).

(3) Next, the resin film for an interlayer resin insulating layer prepared in the above A was laminated by vacuum compression bonding at 0.5 MPa while heating to a temperature of 50 to 150 ° C. Was formed (see FIG. 3D). Further, a through-hole 35 having a diameter of 300 μm is formed on the substrate 30 to which the resin film layer 50α is attached by drilling.
Was formed (see FIG. 3E).

(4) Next, on the resin film layer 50α,
Through a mask in which a 1.2 mm thick through hole is formed,
Using a CO ₂ gas laser with a wavelength of 10.4 μm, a beam diameter of 4.0 mm, a top hat mode, and a pulse width of 8.0 μ
Under the condition of a diameter of the through hole of the mask of 1.0 mm and one shot, an opening 52 for a via hole having a diameter of 80 μm was formed in the resin film layer 50α to form an interlayer resin insulating layer 50 (see FIG. 4A). .

(5) The substrate in which the via hole opening 52 was formed was immersed in a solution containing 60 g / l of permanganic acid at 80 ° C. for 10 minutes, and the wall surface of the through-hole 35 was subjected to desmear treatment. By dissolving and removing the epoxy resin particles present on the surface of the layer 50α, the roughened surface 50 including the inner wall surface of the via hole opening 52 is formed.
a and 52a were formed (see FIG. 4B).

(6) Next, the substrate after the above processing is
It was immersed in a Japanese solution (manufactured by Shipley Co.) and then washed with water. Sa
Furthermore, the surface of the substrate subjected to a surface roughening treatment (roughening depth 3 μm)
By applying a palladium catalyst to the
The surface of the edge layer 50 (including the inner wall surface of the via hole opening 52)
And catalyst nuclei are attached to the wall surfaces of the through holes 35.
(Not shown). That is, palladium chloride
(PbCl_Two ) And stannous chloride (SnCl) _Two ) And
Immersed in a catalyst solution to precipitate palladium metal
More catalyst was applied.

(7) Next, the substrate is immersed in an electroless copper plating aqueous solution having the following composition, and the surface of the interlayer resin insulating layer 50 (including the inner wall surface of the via hole opening 52) and
An electroless copper plating film 42 having a thickness of 0.6 to 3.0 μm was formed on the wall surface of the through hole 35 (see FIG. 4C). [Electroless plating aqueous solution] NiSO ₄ 0.003 mol / l tartaric acid 0.200 mol / l copper sulfate 0.030 mol / l HCHO 0.050 mol / l NaOH 0.100 mol / l α, α'-bipyridyl 100 mg / l Polyethylene glycol (PEG) 0.10 g / l [Electroless plating conditions] 40 minutes at a liquid temperature of 34 ° C

(8) Next, a commercially available photosensitive dry film is attached to the substrate on which the electroless copper plating film 42 has been formed.
A mask was placed and exposed at 100 mJ / cm ² .
By developing with an 8% aqueous sodium carbonate solution,
A plating resist 43 having a thickness of 20 μm was provided (FIG. 4).
(D)).

(9) Next, the substrate was washed with water at 50 ° C., degreased, washed with water at 25 ° C., further washed with sulfuric acid, and then subjected to electrolytic plating under the following conditions to obtain plating resist 43. An electrolytic copper plating film 44 having a thickness of 20 μm was formed in the formation portion (see FIG. 4E). [Electroplating solution] Sulfuric acid 2.24 mol / l Copper sulfate 0.26 mol / l Additive 19.5 ml / l (Atotech Japan, Capparaside GL) [Electroplating conditions] Current density 1 A / dm ² hours 65 minutes Temperature 22 ± 2 ℃

(10) Further, the plating resist 43 is
% KOH, the electroless plated film under the plating resist 43 is dissolved and removed by etching with a mixed solution of sulfuric acid and hydrogen peroxide, and the through-hole conductor layer 3 is removed.
6, and upper layer conductor circuit (including via hole 46)
(See FIG. 5A).

(11) Next, the conductor layer 3 for a through hole
6 is formed in an etching solution to form roughened surfaces 36a and 46a on the surfaces of the through-hole conductor layer 36 and the upper conductor circuit (including the via hole 46) (FIG. 5 (B)). )reference). In addition, as an etching solution, an etching solution (Mec etch bond, manufactured by Mec Co.) comprising 10 parts by weight of an imidazole copper (II) complex, 7 parts by weight of glycolic acid, and 5 parts by weight of potassium chloride was used.

(12) Next, after preparing the resin composition for filling through-holes described in B above, the conductor layer 36 for through-holes was formed on the wall surface within 24 hours after the preparation by the following method.
The resin composition for filling a through hole was filled in the through hole 35 in which was formed and in the via hole 46 on one side of the substrate 30. That is, first, using a rubber squeegee, setting the angle of the squeegee to 14 ° and pushing the resin composition for filling the through-hole into the through-hole 35, followed by drying at 100 ° C. for 20 minutes. . Next, a mask having an opening corresponding to the via hole 46 is placed on the substrate, and the via hole 46 is filled with the through hole filling resin composition using a squeegee,
Drying was performed at 100 ° C. for 20 minutes. Further, similarly, the resin composition for filling a through-hole was filled in the via hole 46 on the other surface of the substrate. Then at 100 ° C
By performing the heat treatment at 150 ° C. for 1 hour,
The resin composition for filling the through holes is cured to form the resin filler layer 54.
To form a through hole 37 (see FIG. 5C).

(13) Next, on the surface of the interlayer resin insulation layer 50 and the exposed surface of the resin filler layer 54,
A palladium catalyst (not shown) was applied by performing the same treatment as described above. Next, an electroless plating process was performed under the same conditions as in the above (7) to form an electroless plating film 56 on the surface of the interlayer resin insulating layer 50 and on the exposed surface of the resin filler layer 54 (FIG. 6 ( A)).

(14) Next, a plating resist having a thickness of 20 μm was provided on the electroless plating film 56 by the same method as in the above (8) (not shown). Furthermore, the above (9)
Electroplating was performed under the same conditions as described above to form an electroplated film 57 in the portion where the plating resist was not formed. Thereafter, the plating resist and the electroless plating film 56 existing thereunder are removed, and a cover plating layer 58 composed of the electroless plating film 56 and the electrolytic plating film 57 is formed on the through holes 37 and the via holes 46. It was formed (see FIG. 6B).

(15) Next, a roughened surface 58a was formed on the surface of the lid plating layer 58 by using the etching solution (mech etch bond) used in the above (11) (see FIG. 6C). (16) Next, by repeating the above steps (3) to (11), an upper interlayer resin insulation layer 60 and a conductor circuit (including via holes 66) are further formed, and a multilayer wiring board is obtained ( FIG. 6D). In this step, no through hole was formed.

(17) Next, a cresol novolak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.) dissolved in diethylene glycol dimethyl ether (DMDG) so as to have a concentration of 60% by weight was used. Oligomer for imparting properties (molecular weight: 4000) 46.6
7 parts by weight, 80% by weight dissolved in methyl ethyl ketone
Of bisphenol A type epoxy resin (manufactured by Yuka Shell Co., Ltd.
Trade name: Epicoat 1001) 15.0 parts by weight, imidazole hardener (manufactured by Shikoku Chemicals, trade name: 2E4MZ-C)
N) 1.6 parts by weight, a bifunctional acrylic monomer which is a photosensitive monomer (trade name: R604, manufactured by Nippon Kayaku Co., Ltd.) 4.5
Parts by weight, also polyvalent acrylic monomer (manufactured by Kyoei Chemical Co.,
A trade name: 1.5 parts by weight of DPE6A) and 0.71 parts by weight of a dispersion defoaming agent (manufactured by San Nopco, S-65) are placed in a container, stirred and mixed to prepare a mixed composition, and the mixed composition is prepared. Of benzophenone (manufactured by Kanto Chemical Co., Ltd.) as a photopolymerization initiator and 0.2 part by weight of Michler's ketone (manufactured by Kanto Chemical Co., Ltd.) as a photosensitizer at 25 ° C. A solder resist composition adjusted to 2.0 Pa · s was obtained. The viscosity was measured with a B-type viscometer (DVL-B type, manufactured by Tokyo Keiki Co., Ltd.) when the rotor No. was 60 rpm. In the case of 4, 6 rpm, the rotor No. 3
According to

(18) Next, the above-mentioned solder resist composition is applied to both sides of the multilayer wiring board in a thickness of 20 μm.
A drying treatment was performed at 70 ° C. for 20 minutes and at 70 ° C. for 30 minutes to form a solder resist composition layer 70α (see FIG. 7A). Next, a 5 mm-thick photomask on which the pattern of the solder resist opening is drawn is brought into close contact with the solder resist layer, exposed to ultraviolet light of 1000 mJ / cm ² , developed with a DMTG solution, and developed with a 200 μm solution.
An opening 71 having a diameter of m was formed. And furthermore, 80
1 hour at 100 ° C, 1 hour at 100 ° C, 1 hour at 120 ° C,
Heat treatment is performed at 50 ° C. for 3 hours to cure the solder resist layer.
A 0 μm solder resist layer 70 was formed (FIG. 7).
(B)). In addition, a commercially available solder resist composition can also be used as the solder resist composition.

(19) Next, the solder resist layer 70 is
The formed substrate is coated with nickel chloride (2.3 × 10^-1mol
/ L), sodium hypophosphite (2.8 x 10^-1mol
/ L), sodium citrate (1.6 x 10^-1mol /
2) in the electroless nickel plating solution having pH = 4.5 containing l)
Immerse in nickel for 0 minutes and put 5μm thick nickel
A plating layer 72 was formed. In addition, the substrate is
Potassium (7.6 × 10 ^-3mol / l), ammonium chloride
Um (1.9 × 10^-1mol / l), sodium citrate
(1.2 × 10^-1mol / l), sodium hypophosphite
(1.7 × 10 ^-1mol / l)
Immersed in the solution at 80 ° C for 7.5 minutes,
A gold plating layer 74 having a thickness of 0.03 μm is formed on the metal layer 72.
(See FIG. 7C).

(20) Thereafter, tin-tin is placed in the opening 71 of the solder resist layer 70 on the surface of the substrate on which the IC chip is to be mounted.
Solder paste containing lead is printed and reflowed at 200 ° C. to form a solder bump (solder body) 76, and on the other surface, a solder paste is printed and a conductive connection pin 78 is attached. Thus, a multilayer printed wiring board was manufactured (see FIG. 8).

(Example 2) In the same manner as in Example 1 except that the squeegee angle was set to 8 ° and the resin composition for filling through holes was filled in the step (12) of Example 1, A multilayer printed wiring board was manufactured.

(Comparative Example 1) In the same manner as in Example 1 except that the squeegee angle was set to 30 ° and the resin composition for filling through holes was filled in the step (12) of Example 1, A multilayer printed wiring board was manufactured.

(Comparative Example 2) In the same manner as in Example 1, except that the squeegee angle was set to 2 ° and the resin composition for filling through holes was filled in the step (12) of Example 1, A multilayer printed wiring board was manufactured.

With respect to the multilayer printed wiring boards obtained in Examples 1 and 2 and Comparative Examples 1 and 2, the shape of the surface portion of the resin filler layer was observed by the following method, and a conduction test was performed. The results are shown in Table 1.

[0163]Observation of the shape of the surface layer of the resin filler layer  Cut the multilayer printed wiring board vertically to include through holes
And observe the shape of the surface of the resin filler layer with a microscope
did.

[0164]

[Table 1]

As shown in Table 1, in the multilayer printed wiring boards of Examples 1 and 2, the shape of the surface portion of the resin filler layer was flat, and the result of the conduction test was good. On the other hand, in the multilayer printed wiring board of Comparative Example 1, the shape of the surface layer portion of the resin filler layer was depressed. In addition, when a conduction test was performed, conduction failure was confirmed. This poor conduction is presumed to be due to poor connection between the conductor layer for through-holes and the cover plating layer.

Further, the multilayer printed wiring board of Comparative Example 2
The shape of the surface layer portion of the resin filler layer was a raised shape. In addition, when a conduction test was performed, conduction failure was confirmed. This poor conduction is presumed to be due to poor connection between the conductor layer for through-holes and the cover plating layer.

[0167]

As described above, in the method for manufacturing a multilayer printed wiring board according to the present invention, when the resin composition for filling through holes is filled with a squeegee, the angle of the squeegee is set to 3 to 10 degrees.
Since the angle is set to 25 °, the inside of the through-hole is completely filled with the through-hole filling resin composition, and the through-hole is formed so that the surface layer of the through-hole filling resin composition becomes flat. Since the filling resin composition can be filled, a multilayer printed wiring board having excellent connection reliability can be manufactured.

[Brief description of the drawings]

FIGS. 1A to 1D are partial cross-sectional views showing a part of steps of a method for manufacturing a multilayer printed wiring board according to the present invention.

FIGS. 2A to 2C are partial cross-sectional views illustrating the shape of the resin composition for filling a through hole when the resin composition for filling a through hole is filled using a squeegee.

FIGS. 3A to 3E are cross-sectional views illustrating some of the steps of the method for manufacturing a multilayer printed wiring board according to the present invention.

FIGS. 4A to 4E are cross-sectional views illustrating some of the steps of a method for manufacturing a multilayer printed wiring board according to the present invention.

FIGS. 5A to 5C are cross-sectional views illustrating some of the steps of the method for manufacturing a multilayer printed wiring board according to the present invention.

FIGS. 6A to 6D are cross-sectional views illustrating some of the steps of the method for manufacturing a multilayer printed wiring board according to the present invention.

FIGS. 7A to 7C are cross-sectional views illustrating some of the steps of the method for manufacturing a multilayer printed wiring board according to the present invention.

FIG. 8 is a sectional view showing an embodiment of the multilayer printed wiring board of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 30 substrate 32 copper foil 34 lower conductive circuit 35 through hole 52 via hole opening 42 electroless plating film 43 plating resist 44 electrolytic plating film 50 interlayer resin insulation layer 54 resin filler layer 58 lid plating layer 70 solder resist layer 76 solder bump 78 Conductive pin

Continued on the front page F-term (reference) 5E317 AA24 BB01 BB11 CC31 CC53 CD23 CD27 GG01 GG09 5E346 AA02 AA04 AA12 AA15 AA29 AA32 AA42 AA43 CC04 CC09 CC32 CC55 DD22 EE13 EE19 FF01 FF13 FF14 FF17 GG11 HGGFF

Claims (3)

[Claims] 1. A through-hole forming step of forming a through-hole in a substrate having a conductor circuit and an interlayer resin insulating layer formed on each side thereof, a wall surface in the through-hole, A conductor layer forming step of forming a conductor layer on part of the surface, and a resin filling step of filling a through hole filling resin composition using a squeegee into the through hole in which the conductor layer is formed on the wall surface; A method for manufacturing a multilayer printed wiring board, comprising: drying and curing the resin composition for filling a through hole, and forming a through hole in which a resin filler layer is formed. A method for manufacturing a multilayer printed wiring board, wherein an angle of a squeegee is set at 3 to 25 ° in a resin filling step. 2. The resin composition for filling a through hole to be filled in the resin filling step includes an epoxy resin, a curing agent, and inorganic particles, and the content ratio of the inorganic particles after curing is 10 to 5
The method for producing a multilayer printed wiring board according to claim 1, wherein the resin composition is 0% by weight. 3. The method for manufacturing a multilayer printed wiring board according to claim 1, further comprising a lid plating layer forming step of forming a lid plating layer covering the through hole after completion of the through hole forming step.