CN111378252A - Resin filler - Google Patents

Abstract

The present invention relates to a resin filler, a cured product, a printed wiring board, and a method for producing a printed wiring board. The resin filling material contains (A) epoxy resin, (B) curing agent, and (C) polyurethane particles.

Description

Resin filler

Technical Field

The present invention relates to a resin filler, and more particularly to a resin filler useful as a composition for permanently filling holes such as through holes and via holes in printed wiring boards such as multilayer boards and double-sided boards. The present invention also relates to a printed wiring board obtained by permanently filling holes and recesses such as through holes and via holes with the composition. In the present specification, the "concave portion" refers to a via hole or the like for the purpose of conduction between layers of the printed wiring board, and the "hole portion" refers to a through hole, for example, a through hole, for the purpose of conduction between the front surface and the back surface of the printed wiring board.

Background

The printed wiring board has a conductor circuit pattern formed on a base material, an electronic component is mounted on a pad portion of the conductor circuit by soldering, and a solder resist is coated on a circuit portion other than the pad portion in order to protect the conductor. Thus, the solder resist film has the following functions: solder is prevented from adhering to unnecessary portions when mounting electronic components on a printed circuit board, and oxidation or corrosion of a circuit is prevented.

In recent years, the reduction in the size of conductor circuit patterns and the reduction in the mounting area of printed wiring boards have been advanced, and further reduction in the thickness and size of printed wiring boards have been desired in order to further cope with the miniaturization and high functionality of devices provided with printed wiring boards. Therefore, the following multilayer printed circuit boards were developed: a multilayer printed wiring board formed by filling a resin filler into a through hole provided in a printed wiring board, curing the resin filler to form a smooth surface, and then alternately laminating an interlayer resin insulation layer and a conductor circuit layer on the circuit board; or a multilayer printed wiring board in which a solder resist is directly formed on a substrate having a hole such as a through hole filled with a resin filler. Under such circumstances, it has been desired to develop a composition for permanent hole filling which is excellent in printability for filling holes and recesses such as through holes and via holes and cured product properties such as solder heat resistance (see WO 2002/044274).

In such a multilayer printed wiring board, a hole portion such as a through hole having a copper plating layer formed therein is formed to electrically connect the respective layers. In the process of manufacturing a printed wiring board, a filler of a curable resin composition called a hole-filling ink is filled into a hole portion such as a through hole, from the viewpoint of ensuring the strength of the printed wiring board and preventing contamination.

Disclosure of Invention

Problems to be solved by the invention

The electronic product is heated and cooled in the use environment, and the printed circuit board is repeatedly expanded and contracted. The compositions of prior art via-filling inks are sometimes less than the Coefficient of Thermal Expansion (CTE) of the substrate to be via-filled. Thus, peeling of the copper plating layer on the upper portion of the filled hole and generation of cracks on the solder ball may occur due to a mismatch with the thermal expansion of the base material at the time of the reflow process.

In the case where the CTE of the base material is large, for example, a resin substrate having a thermal expansion coefficient (CTE (α 2)) of 200ppm or more in a region of Tg or more must be adapted with the hole-filling ink, and adhesion to the copper plating layer must be improved.

For example, in the prior art (Japanese patent application laid-open No. 2010-37544) using a filler having a particle size of 1 μm or less such as barium sulfate, the CTE is not sufficiently increased. And viscosity increases and printability deteriorates.

Further, in the prior art (jp 2007-250996 a) in which an inorganic filler and silicone as an organic filler are used together, peeling of the plating layer and cracking of the hole-filled portion occur after reflow soldering.

The present invention has been made in view of the above-described problems of the prior art, and a basic object thereof is to provide a resin filling material for filling holes, a cured product, a printed wiring board, and a method for manufacturing the printed wiring board, which are capable of obtaining a printed wiring board that has a cured product with sufficient polishing properties, and that is excellent in printability when filling holes, without problems such as peeling of a copper plating layer on the upper portion of the filled holes and generation of cracks in the solder balls under high temperature conditions such as curing treatment and solder leveling.

Means for solving the problems

In order to solve the above problems, the inventors thought that stress on the outer layer can be reduced by increasing the CTE to approach the thermal expansion of the base material, and further, as a result of extensive and repeated studies, found that a pore-filling ink having a high CTE and excellent polishing properties and printability can be obtained by including polyurethane particles in the resin filler.

As a result, the inventors succeeded in obtaining a resin filler for via filling which is free from problems such as peeling of a copper plating layer on a via filling part and generation of cracks in a solder ball, has a cured product with sufficient polishing properties, and is excellent in printability when filling a via part, and completed the present invention.

That is, the present invention relates to the following.

(1) A resin filling material characterized by containing (A) an epoxy resin, (B) a curing agent, and (C) polyurethane particles.

(2) The resin filler according to (1), wherein the epoxy resin (A) is at least 1 epoxy resin selected from the group consisting of a bisphenol A type epoxy resin, a phenol novolac type epoxy resin, and an aminophenol type epoxy resin.

(3) The resin filling material according to (1) or (2), wherein the curing agent (B) is an imidazole curing agent.

(4) The resin filler according to (1) or (2), which further contains an organic filler and/or an inorganic filler other than the polyurethane particles.

(5) The resin filling material according to (4), wherein the organic filler other than the polyurethane particles is at least 1 organic filler selected from the group consisting of silicone rubber and acrylic microparticles.

(6) The resin filler according to (4), wherein the inorganic filler is at least 1 inorganic filler selected from the group consisting of barium sulfate, calcium carbonate and silica.

(7) The resin filler according to any one of (1) to (6), which is a resin filler for at least one of a recess or a hole of a printed circuit board.

(8) A cured product obtained by filling at least one of a concave portion and a hole portion of a printed wiring board with the resin filler according to any one of (1) to (7) and curing the resin filler.

(9) A printed wiring board using the resin filler according to any one of (1) to (7).

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention provides a resin filling material for filling holes, which can obtain a cured product having sufficient polishing properties without problems such as peeling of a copper plating layer on the top of the filled hole and generation of cracks in a solder ball, and which has excellent printability when filling a hole. The resin filler of the present invention is most suitable for filling holes and recesses such as through holes and via holes in printed wiring boards, and therefore can be used for permanent insulating hole filling.

The present invention also provides a cured product having sufficient polishing properties without the problems of peeling of a copper plating layer on a via-filling portion and generation of cracks in a solder ball under high temperature conditions such as curing treatment and solder leveling, a printed wiring board having the cured product, and a method for producing the printed wiring board.

Drawings

Fig. 1 is a schematic cross-sectional view showing an example of a part of a process for manufacturing a printed wiring board according to the present invention.

Fig. 2 is a schematic cross-sectional view showing an example of a process after the process of manufacturing the printed wiring board of the present invention shown in fig. 1.

FIG. 3 is a schematic sectional view showing another example of the method for manufacturing a printed wiring board according to the present invention.

Description of the reference numerals

1 substrate

2 copper foil

3 through hole

4a, 4b, 4c, 4d coating film

5 resin filler

6 Corrosion resistant coating

7a, 7b, 7c conductor circuit layer

8a, 8b interlayer resin insulation layer

9a, 9b openings

10 plating resist

11 through hole

12 bonding pad

13 solder resist layer

14 solder bump

Detailed Description

The present invention is a resin filling material characterized by containing (A) an epoxy resin, (B) a curing agent, and (C) polyurethane particles. The resin filler of the present invention contains polyurethane particles, and therefore, can form a cured product which has sufficient polishing properties without the problems of peeling of the copper plating layer on the top of the filled hole and the occurrence of cracks in the solder ball under high temperature conditions such as curing treatment and solder leveling. The resin filler of the present invention is excellent in printability and therefore is very suitable for filling holes and recesses such as through holes and via holes in printed wiring boards.

Hereinafter, "resin filling material for filling holes of a printed circuit board" and "resin filling material for filling holes" are sometimes simply referred to as "resin filling material".

The present invention will be described in detail below.

(A) Epoxy resin

The resin filling material of the present invention is preferably solvent-free because it is used as a hole filling material for a printed circuit board, and therefore, a liquid epoxy resin is suitable. From the above-described viewpoint, bisphenol a type epoxy resin, bisphenol E type epoxy resin, bisphenol F type epoxy resin, aminophenol type epoxy resin, phenol novolac type epoxy resin are preferably used as the resin filler of the present invention. In the resin filler of the present invention, the epoxy resin may be used alone, or 2 or more kinds thereof may be used simultaneously. When a solid epoxy resin is used instead of a liquid epoxy resin, a curing agent and a filler, which will be described later, may be dispersed in the solid epoxy resin using a solvent.

As a commercially available product of the epoxy resin (A), there can be mentioned (A-1) a bisphenol A type epoxy resin which is liquid at room temperature. For example, bisphenol A type epoxy resins, liquid bisphenol E type epoxy resins, liquid bisphenol F type epoxy resins, liquid phenol novolac type epoxy resins, and aminophenol type liquid epoxy resins having an epoxy equivalent of 300g/eq or less. Specific examples thereof include liquid bisphenol A type epoxy resins such as jER825, jER827, jER828EL, jER828US, jER828XA, YD-8125, YD-127, YD-825GS, YD-825GSH manufactured by Mitsubishi chemical corporation, EP-4100 manufactured by ADEKA corporation, EP-4100G, EP-4100E, EP-4100TX, EP-4300E, EP-4400, EP-4520S, EP-4530, EPICLON 840-S, EPICLON 850, EPICLON EXA-850CRP and EPICLON 850-LC (trade names); liquid bisphenol F-type epoxy resins such as jER806, jER806H, jER807 manufactured by Mitsubishi chemical corporation, YD-170 manufactured by Nippon Tekko & materials, YD-8170, YDF-8170C, TDF-870GS, ZX-1059, EP-4901 manufactured by ADEKA corporation, EPICLON 830-S, EPICLON 835, EPICLON EXA-830CRP, EPICLON EXA-830LVP, and EPICLON EXA-835LV (trade names); a liquid phenol novolac type epoxy resin of DEN431 (trade name) manufactured by dow chemical; aminophenol type liquid epoxy resins (p-aminophenol type liquid epoxy resins) of jER630 manufactured by mitsubishi chemical corporation and ELM-100 (both trade names) manufactured by sumitomo chemical corporation; liquid bisphenol E type epoxy resin of R710 (trade name) manufactured by PRINTEC corporation; these can be used alone or in combination of 2 or more.

As a commercially available product of the epoxy resin (A), there can be mentioned (A-2) an epoxy resin having 2 or more epoxy groups in 1 molecule which is solid at room temperature. As the epoxy resin (A-2) having 2 or more epoxy groups in 1 molecule which is solid at room temperature, those known in the art can be used. For example, there may be mentioned: bisphenol A type epoxy resins such as jER1001, jER1004 manufactured by Mitsubishi chemical corporation, EPICLON 1050, EPICLON 1055, EPICLON 2050, EPICLON 3050, EPICLON4050, EPICLON 7050, EPICLON HM-091 and EPICLON HM-101 (all trade names); brominated Epoxy resins such as jERYL903 manufactured by Mitsubishi chemical corporation, EPICLON 152 and EPICLON 153 manufactured by DIC corporation, Epotohto YDB-400 and YDB-500 manufactured by Tokyo chemical Co., Ltd, D.E.R.542 manufactured by Dow chemical Co., Ltd, Araldite8011 manufactured by BASFJAPAN corporation, Sumi-Epoxy ESB-400 and ESB-700 manufactured by Sumitomo chemical industry Co., Ltd, A.E.R.711 and A.E.R.714 manufactured by Asahi chemical Co., Ltd (trade names); jer152, Jer154, D.E.N.431, D.E.N.438, EPICLON N-660, EPICLON-665, EPICLON-670, EPICLON-673, EPICLONN-680, EPICLON-690, EPICLON-695, EPICLON-665-EXP, EPICLON-672-EXP, EPICLONN-665-EXP-S, EPICLON-662-EXP-S, EPICLON-665-EXP-S, EPICLON-670-EXP-S, EPICLON-685-EXP-S, EPICLON-730, EPICLON-865-EXP-S, EPICLON-670-EXP-S, EPICLON-685-EXP-S, EPICLON-865-EXP-S, EPICLON-770-ETICLON-1273, ECALYDN-1273, EPICLON-S, EPICLON-O-, AralditeXPY307, EPPN-201, EOCN-1025, EOCN-1020, EOCN-104S, RE-306 manufactured by Nippon chemical Co., Ltd., Sumi-EpoxyESCN-195X, ESCN-220 manufactured by Sumitomo chemical Co., Ltd., A.E.R.ECN-235 manufactured by Asahi chemical Co., Ltd., ECN-299, and the like (trade names) are novolak-type epoxy resins; trishydroxyphenylmethane-type epoxy resins such as YL-933 manufactured by Mitsubishi chemical corporation, T.E.N. manufactured by Dow chemical Co., Ltd., EPPN-501, EPPN-502, and the like (trade names); bisphenol type or biphenol type epoxy resins such as YL-6056, YX-4000 and YL-6121 (trade names) manufactured by Mitsubishi chemical corporation, or a mixture thereof; bisphenol S type epoxy resins such as EBPS-200 manufactured by Nippon Kabushiki Kaisha, EPX-30 manufactured by ADEKA Kaisha, and EXA-1514 (trade name) manufactured by DIC Kaisha; bisphenol a novolac type epoxy resins such as jER157S (trade name) manufactured by mitsubishi chemical corporation; tetrahydroxyphenyl ethane type epoxy resins such as jERYL-931 manufactured by Mitsubishi chemical corporation and Araldite163 manufactured by BASF JAPAN corporation (both trade names); heterocyclic epoxy resins such as Araldite PT810 available from BASF JAPAN corporation and TEPIC available from Nissan chemical industries, both of which are trade names; diglycidyl phthalate resin such as BLEMMER DDT manufactured by japan fat and oil co; tetraglycidyl xyleneoylethane resin (tetraglycidyl xyleneethanothane resin) such as ZX-1063 manufactured by Tokyo Kabushiki Kaisha; naphthyl group-containing epoxy resins such as ESN-190, ESN-360, produced by Nippon Tekko & materials, EXA-4750 and EXA-4700, produced by DIC; epoxy resins having a dicyclopentadiene skeleton such as HP-7200 and HP-7200H manufactured by DIC; glycidyl methacrylate-copolymerized epoxy resins such as CP-50S, CP-50M manufactured by Nippon fat and oil Co., Ltd; further, a copolymerized epoxy resin of cyclohexylmaleimide and glycidyl methacrylate; epoxy-modified polybutadiene rubber derivatives (e.g., PB-3600 manufactured by Celite chemical industries, Ltd.), CTBN-modified epoxy resins (e.g., YR-102 and YR-450 manufactured by Tokyo Kasei K.K.), and the like, but are not limited thereto.

These epoxy resins may be used alone or in combination of 2 or more. Among them, at least 1 kind of epoxy resin selected from the group consisting of bisphenol a type epoxy resin, phenol novolac type epoxy resin, and aminophenol type epoxy resin is particularly preferable.

(B) Curing agent

Examples of the curing agent (B) of the present invention include curing agents for resin fillers such as imidazole curing agents.

Examples of the imidazole-based curing agent include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1- (2-cyanoethyl) -2-ethyl-4-methylimidazole.

Examples of commercially available products include 2MZ-A, 2MZA-PW, 2MZ-OK, 2PHZ, 2P4BHZ and 2P4MHZ (both trade names of imidazole compounds) manufactured by chemical industries, Inc.

The curing agent is not particularly limited to those mentioned above, and may be used alone or in combination of 2 or more kinds as long as it is a curing agent for epoxy resin.

Further, s-triazine derivatives such as guanamine, methylguanamine, benzoguanamine, melamine, 2, 4-diamino-6-methacryloyloxyethyl-s-triazine, 2-vinyl-2, 4-diamino-s-triazine, 2-vinyl-4, 6-diamino-s-triazine-isocyanuric acid adduct, and 2, 4-diamino-6-methacryloyloxyethyl-s-triazine-isocyanuric acid adduct may be used, and it is preferable to use these compounds also functioning as an adhesion imparting agent in combination with the aforementioned heat curing agent.

The compounding amount of the curing agent may be a conventional amount. The amount of the epoxy resin is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 15.0 parts by mass, per 100 parts by mass of the epoxy resin (A).

(C) Polyurethane particles

The polyurethane particles (C) of the present invention are not particularly limited as long as they are obtained by granulating polyurethane. Examples of commercially available products include UCN-5070D manufactured by Daihai chemical industries, Ltd, and JB-800T manufactured by Gentiansu chemical industries, Ltd.

The average particle diameter d50 of the polyurethane particles (C) is preferably 0.1 to 25 μm. More preferably 1 to 10 μm. When the average particle diameter is 0.1 μm or more, the specific surface area can be reduced, the dispersibility can be improved, and the filling amount of the (C) polyurethane particles can be easily adjusted. On the other hand, when the thickness is 25 μm or less, the filling property into the hole of the package substrate for mounting a semiconductor is good, and the smoothness is good when the conductor layer is formed in the portion after the hole is filled.

(C) The amount of the polyurethane particles to be blended is preferably 10 to 200 parts, more preferably 20 to 150 parts, and still more preferably 30 to 100 parts, based on 100 parts of the epoxy resin (a). (C) When the amount of the polyurethane particles is 10 parts or more, the CTE of the cured product obtained can be easily made sufficiently large, and the crack resistance is excellent, and further, sufficient polishing properties, heat resistance, and printability can be obtained. When the amount is 200 parts or more, the printability and heat resistance are deteriorated, which is not preferable.

In the present invention, a known inorganic filler and/or an organic filler other than polyurethane particles, which are used in a general resin filler, can be used.

Examples of the inorganic filler include non-metallic fillers such as silica, barium sulfate, calcium carbonate, silicon nitride, aluminum nitride, boron nitride, alumina, magnesium oxide, aluminum hydroxide, magnesium hydroxide, titanium oxide, mica, talc, and organobentonite; copper, gold, silver, palladium, silicon and other metal fillers.

As the organic filler other than the polyurethane particles, a known organic filler can be used. Examples thereof include rubber particles such as silicone rubber, acrylic rubber, NBR, MBS and SBR; resin particles made of resins such as acrylic resins, styrene resins, phenol resins, epoxy resins, polyamide resins, polyimide resins, and fluorine resins. These inorganic fillers and/or organic fillers other than the polyurethane particles may be used alone or in combination of 2 or more.

The shape of the inorganic filler and the organic filler other than the polyurethane particles may be spherical, acicular, flaky, scaly, hollow, irregular, hexagonal, cubic, flaky, etc., and spherical is preferable from the viewpoint of high filling of the filler.

The average particle diameter d50 of the inorganic filler and the organic filler other than the polyurethane particles is preferably 0.1 to 25 μm. When the average particle diameter is 0.1 μm or more, the specific surface area can be reduced, the dispersibility can be improved, and the filling amount of the filler can be easily increased. On the other hand, when the thickness is 25 μm or less, the hole portion of the package substrate for mounting a semiconductor device is well filled, and smoothness is good when the conductor layer is formed in the portion after the hole filling. More preferably 1 to 10 μm.

The amount of the inorganic filler and the organic filler other than the polyurethane particles is preferably 10 to 100 parts, more preferably 15 to 80 parts, and still more preferably 20 to 50 parts, based on 100 parts of the (a) epoxy resin. When the amount of the filler is 10 parts or more, the thermal expansion of the resulting cured product can be suppressed, the crack resistance is excellent, and sufficient polishing properties and adhesion can be obtained. On the other hand, when the amount is 100 parts or less, the paste can be easily prepared, and good printability and good filling property of filling holes can be obtained.

Other known additives may be added to the resin filler of the present invention as needed. For example, known and commonly used colorants such as phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black, and naphthalene black, known and commonly used thermal polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, t-butyl catechol, pyrogallol, and phenothiazine for imparting storage stability during storage, known and commonly used thickeners or thixotropic agents such as clay, kaolin, organic bentonite, and montmorillonite, defoaming agents and/or leveling agents such as organosilicone, fluorine, and polymer, and known and commonly used additives such as adhesion imparting agents such as imidazole, thiazole, triazole, and silane coupling agents may be added. In particular, when organobentonite is used, the portion which overflows from the surface of the hole is easily formed into a protruding state which is easy to polish and remove, and the polishing property is excellent, so that it is preferable.

As described above, when the resin filler of the present invention is used as a hole-filling material for a printed circuit board, the epoxy resin is preferably a liquid, and a solid epoxy resin may be dissolved in a solvent and used. In the above case, as the solvent, ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents, and the like can be used. Specific examples thereof include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, dipropylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol butyl ether acetate, methyl lactate, ethyl lactate, and butyl lactate; alcohols such as ethanol, propanol, ethylene glycol, and propylene glycol; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, naphtha, hydrogenated naphtha, and solvent naphtha. These solvents may be used alone or in combination of 2 or more. The amount of the solvent to be added may be determined as appropriate based on the workability and the like within a range in which the desired effects of the present invention can be obtained.

Next, the printed wiring board of the present invention will be explained.

The printed wiring board of the present invention is a printed wiring board having a cured product formed from the resin filler of the present invention in a hole portion formed in a base material. The method for manufacturing a printed wiring board according to the present invention will be described in detail below with reference to fig. 1 to 3.

Formation of vias

Fig. 1 is a schematic cross-sectional view showing an example of a part of a process for manufacturing a printed wiring board according to the present invention, first, as shown in fig. 1 (a), a through hole is formed in a substrate 1 on which a copper foil 2 is laminated by a drill or the like, and a wall surface of the through hole and a surface of the copper foil are electroless-plated to form a through hole 3. as the substrate 1, a resin substrate such as a glass epoxy substrate, a polyimide substrate, a bismaleimide-triazine resin substrate, or a fluororesin substrate, or a copper clad laminate of these resin substrates, a ceramic substrate, a metal substrate, or the like can be used.

Next, plating is performed to increase the thickness, and as shown in fig. 1 (b), a plating film 4a is formed on the surface of the substrate 1 and on the inner wall of the through-hole 3. As the plating, copper plating is preferable.

Hole filling

As shown in fig. 1 (c), a through-hole 3 formed in a substrate 1 is filled with a resin composition 5 of the present invention. Specifically, a mask having an opening in the through-hole 3 is placed on the substrate 1, and the organic solvent is used to adjust the viscosity to a level suitable for the application method, so that the mask can be easily filled into a hole such as a via hole or a through-hole by screen printing, roll coating, die coating, or the like. Next, after the resin filler 5 is heated at about 80 to 180 ℃ for about 30 to 90 minutes to be cured, unnecessary portions of the resin filler 5 that have overflowed from the through-hole 3 are removed by polishing, and planarization is performed, as shown in fig. 1 (d). The grinding can be performed by a belt sander, a polishing grinder, or the like.

Formation of conductor circuit layer

As shown in fig. 1 (e), a plating film 4b is formed on the surface of the substrate 1 in which the through-hole 3 is filled. Then, as shown in fig. 1 (f), a resist 6 is formed, and a portion where no resist is formed is etched. Next, the resist coating 6 is peeled off, and as shown in fig. 1 (g), a conductor circuit layer 7a is formed.

Formation of interlayer resin insulation layer

Fig. 2 is a schematic cross-sectional view showing an example of a process after the process of manufacturing the printed wiring board of the present invention shown in fig. 1. An interlayer resin insulating layer 8a is formed on the conductor circuit layer 7 a. As the interlayer resin insulation layer 8a, a thermosetting resin, a photocurable resin, a thermoplastic resin, a composite or a mixture of these resins, a glass cloth-impregnated resin composite, or an adhesive for electroless plating can be used.

Formation of via holes

Next, as shown in fig. 2 (a), an opening 9a is provided in the interlayer resin insulation layer 8 a. The opening 9a is perforated by exposure and development treatment when the interlayer resin insulation layer 8a is formed of a photosensitive resin, and by laser light when the interlayer resin insulation layer 8a is formed of a thermosetting resin or a thermoplastic resin. When the opening 9a is provided by laser, desmear treatment can also be performed.

Next, as shown in fig. 2 (b), a plating film 4c is formed over the entire surface. Then, as shown in fig. 2 (c), a plating resist layer 10 is formed on the plated film 4 c. The plating resist layer 10 is preferably formed by laminating photosensitive dry films, and performing exposure and development processes. Further, electroplating is performed to increase the thickness of the conductor circuit portion, thereby forming a plated film 4d as shown in FIG. 2 (c).

Next, after the plating resist layer 10 is peeled off, the electroless plated film 4c under the plating resist layer 10 is removed by etching and dissolution, and as shown in fig. 2 (d), an independent conductor circuit (including a via hole 11a) is formed.

FIG. 3 is a schematic sectional view showing another example of the method for manufacturing a printed wiring board according to the present invention. When the conductor layers on both surfaces of the core substrate 1 are etched in a predetermined pattern after the core substrate manufacturing process shown in fig. 1 (d) is completed, as shown in fig. 3 (a), the 1 st conductor circuit layers 7b having a predetermined pattern are formed on both surfaces of the substrate 1, and the lands 12 are simultaneously formed in a part of the conductor circuit layers 7b connected to the through holes 3.

Next, as shown in fig. 3 (b), interlayer resin insulation layers 8b are formed on both the upper and lower surfaces of the substrate 1. Further, as shown in fig. 3 (c), a via hole 11b is formed in the resin insulating layer 8b located directly above the land 12. Next, plating layers formed by copper plating are formed in the via hole 11b and on the interlayer resin insulation layer 8b, and after a resist coating is formed thereon, etching is performed. Thereby, as shown in fig. 3 (c), the 2 nd conductor circuit layer 7c is formed on the interlayer resin insulation layer 8 b. The 1 st conductor circuit layer 7b and the 2 nd conductor circuit layer 7c are electrically connected to each other through the via hole 11b, and the conductor circuit layers 7b on both surfaces of the substrate are also electrically connected to each other through the through hole 3.

Then, as shown in fig. 3 (c), a solder resist layer 13 is formed on each of the resin insulation layer 8b and the 2 nd conductor circuit layer 7c, and a solder bump 14 is formed in the solder resist layer 13 above, the solder bump 14 penetrating therethrough and standing upright from the surface of the conductor circuit layer. Further, a multilayer circuit board used as a connection terminal can be obtained by performing Au plating and Ni plating on the surface of the conductor circuit layer 7c exposed from the opening 9b formed between the solder resist layers 13 below.

Examples

The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples throughout. Unless otherwise specified, the following "parts" and "%" are based on mass.

The respective components shown in table 1 below were compounded in the proportions (parts by mass) shown in table 1, premixed by a stirrer, and kneaded by a three-roll mill to prepare a resin filler. The results are shown in Table 2.

TABLE 1

TABLE 2

*1: epoxy resin, JeR828 manufactured by Mitsubishi chemical corporation, bisphenol A epoxy resin, epoxy equivalent 184-

*2: epoxy resin, DEN431 (produced by Dow chemical Co., Ltd.), phenol novolac type epoxy resin, epoxy equivalent 172-

*3: epoxy resin, ELM-100 manufactured by Sumitomo chemical Co., Ltd., aminophenol type epoxy resin, epoxy equivalent of about 106

*4: polyurethane particles, UCN-5070D manufactured by Dari chemical industries Co., Ltd., fine polyurethane particles, and an average particle diameter of 7 μm

*5: polyurethane particles, JB-800T manufactured by Kokusan Kogyo Co., Ltd., polyurethane Fine particles, and having an average particle diameter of 6 μm

*6: organic filler, KMP-597 manufactured by shin-Etsu chemical industry, silicone rubber powder, and 5 μm in average particle diameter

*7: organic Filler, MX-500 manufactured by Soken chemical Co., Ltd, acrylic fine particles, and an average particle diameter of 5 μm

*8: inorganic Filler, Sakai chemical corporation B-30, barium sulfate, and average particle diameter of 0.2 μm

*9: an inorganic filler, Softon1500 manufactured by Beibei powdered Industrial Co., Ltd., calcium carbonate, and having an average particle diameter of 1.5 μm

*10: curing agent, 2MZA-PW, 2, 4-diamino-6- [2 '-methylimidazolyl- (1') ] -ethyl-s-triazine manufactured by Sizhou chemical industry Co., Ltd

*11: curing agent, 2PHZ manufactured by Siguo Kabushiki Kaisha, 2-phenyl-4, 5-dihydroxymethylimidazole

< printability >

A liquid resin composition of each of examples and comparative examples was filled into through holes of a glass epoxy substrate (Tg: 170 ℃, CTE α 1/α 2: 50ppm/250mm, and the definitions of CTE α 1 and CTE α 2 are referred to as < measurement of Tg and CTE > below) having through holes with a conductor layer formed by plate plating (panel plating) and having a thickness of 1.6mm, a through hole diameter of 0.25mm, and a through hole pitch of 1 mm) by a screen printing method under the following printing conditions.

< printing conditions >

Scraping plate: the thickness of the scraper is 20mm, the hardness is 70 degrees, and the inclined grinding: 23 degree

Edition: PET100 mesh screen plate, printing pressure: 50kg, blade speed 30mm/s, blade angle: 80 degree

< evaluation criteria for printability >

Confirm 425 holes

◎ filling all through holes with resin

○ through-hole generation 1-2 holes without complete filling with resin

△ through holes not completely filled with resin are 3-50 holes

× through-hole not completely filled with resin occurred over 51 holes

< measurement of Tg and CTE >

The liquid resin compositions of examples and comparative examples were applied to the glossy surface side (copper Foil) of a GTS-MP Foil (manufactured by furukawa circuit Foil co., ltd.) with an applicator, and cured at 150 ℃ for 60 minutes in a hot air circulation type drying furnace, and then the cured product produced by the above method was peeled off from the copper Foil, and then the sample was cut into a measurement size (3mm × mm), and in tma 7100. tma measurement manufactured by hitachi corporation, the sample was heated from room temperature at a heating rate of 10 ℃/min under a test load of 5g, and the glass transition temperature (Tg) was measured twice continuously, and the thermal expansion coefficient (CTE (α) of a region lower than Tg) and the thermal expansion coefficient (CTE (α) of a region higher than Tg were evaluated by setting the intersection point of two tangent lines different in the second thermal expansion coefficient as the glass transition temperature (Tg).

< reflow test >

The liquid resin compositions of examples and comparative examples were filled into through-holes by the same method as described in < printability > above, and then cured at 150 ℃ for 60 minutes in a hot air circulation type drying furnace to cure the resin layer, and the resin portion overflowing from the surface of the substrate was removed by buffing, and then, wet-type desmear treatment with permanganate (commercially available desmear solution: made by ATOTECH), electroless copper treatment (commercially available electroless copper plating solution: THRU-CUPPEA, made by Kokai Co., Ltd.) and electrolytic copper treatment were sequentially performed in this order to obtain an evaluation substrate of a cap plating standard, and the evaluation substrate was subjected to reflow (peak temperature 270 ℃ × 5 cycle) treatment, then cut into through-holes, and the cross-section was observed with an optical microscope to evaluate whether delamination occurred between the top of the via-filling and the copper plating layer and cracking of the via-filling ink according to the following criteria.

< evaluation criteria for copper plating delamination >

◎ No copper plating delamination

Stripping copper plating from the through holes at the ○: 1-3 positions

△ through holes at the positions of 3 to 50 parts of the copper plating layer are stripped

× through hole with more than 50 points to strip copper plating

< evaluation criteria for pore-filling cracks >

◎ No cracking

Cracks occur in the through holes at the positions of ○: 1-3

Cracking occurs in the through holes at the positions of △: 4-50

Cracking of through hole at ×: 51 or more

< abrasiveness >

The liquid resin compositions of the examples and comparative examples were filled in the through-holes in the same manner as described in the < printability > above. Then, the resultant was cured at 150 ℃ for 60 minutes in a hot air circulation drying furnace to obtain an evaluation substrate. The resin portion overflowing from the substrate surface of the test substrate was physically polished by buffing (3M high-cutbuff #320), and the number of passes (number of pass) until the resin of the discharge portion was removed was compared.

◎ grinding can be carried out in a 2-pass process

Good: can be ground in 2 to 3 steps

△ capable of polishing in 4-5 steps

× the flow is more than 6

< peeling Strength >

The liquid resin compositions of examples and comparative examples were applied to the entire surface of a substrate by screen printing, cured by heating at 150 ℃ for 60 minutes, and subjected to a copper plating treatment so as to form a copper thickness of 25 μm on the resin layer by sequentially performing a wet permanganate desmear treatment (commercially available desmear solution for permanganic acid: manufactured by ATOTECH), an electroless copper plating treatment (commercially available electroless copper plating solution for THRU-CUP PEA, manufactured by Shanmura industries, Ltd.), and an electrolytic copper plating treatment in this order. A notch having a width of 10mm and a length of 60mm was cut into the copper plating layer of the test substrate, one end portion thereof was peeled off and held by a jig, and the peel strength (N/cm) at the time of peeling off the copper plating layer having a length of 35mm was measured at an angle of 90 degrees and a speed of 50 mm/min by a bench tensile tester (EZ-SX manufactured by Shimadzu corporation).

< evaluation criteria for peeling Strength >

◎ peel strength of 7.0(N/cm) or more

○ peel strength of 5.0(N/cm) or more and less than 7.0(N/cm)

△ Peel Strength of 3.0(N/cm) or more and less than 4.0(N/cm)

× Peel Strength less than 3.0(N/cm)

As described above, in examples 1 to 4, since the polyurethane particles were contained, the copper plating layer did not peel off even when the hole was filled in the substrate having a large CTE, and the heat resistance, the polishing property, and the printability were excellent. In comparative example 1, when the inorganic filler was used instead of the polyurethane particle, the viscosity became too low, the printability was poor, and the CTE could not be sufficiently large. Comparative example 2 used an inorganic filler having a particle size of 1 μm or less, but the viscosity increased, the printability deteriorated, and the CTE could not be sufficiently increased. In comparative example 3, silicone particles were used instead of polyurethane particles, but the compatibility with the resin was poor, the printability was poor, voids were likely to be generated during printing, and cracks due to voids were generated. In comparative example 4, acrylic particles were used instead of urethane particles, but cracks and peeling of the copper plating layer occurred during reflow soldering due to low heat resistance.

As is apparent from tables 1 and 2, the resin filler of the present invention can provide a cured product which has sufficient polishing properties without problems such as peeling of the copper plating layer on the top of the via-filling and cracking of the solder ball under high temperature conditions such as curing treatment and solder leveling, and is suitable for via-filling of printed wiring boards because of its excellent printability, and is particularly suitable for resin substrates having a CTE (α 2) of 200ppm or more.

Claims (9)

1. A resin filling material characterized by containing (A) an epoxy resin, (B) a curing agent, and (C) polyurethane particles.

2. The resin filling material according to claim 1, wherein the epoxy resin (a) is at least 1 epoxy resin selected from the group consisting of a bisphenol a type epoxy resin, a phenol novolac type epoxy resin, and an aminophenol type epoxy resin.

3. The resin filling material according to claim 1 or 2, wherein the curing agent (B) is an imidazole-based curing agent.

4. The resin filler according to claim 1 or 2, further comprising an organic filler and/or an inorganic filler other than the polyurethane particles.

5. The resin filling material according to claim 4, wherein the organic filler other than the polyurethane particles is at least 1 organic filler selected from the group consisting of silicone rubber and acrylic microparticles.

6. The resin filler according to claim 4, wherein the inorganic filler is at least 1 kind of inorganic filler selected from the group consisting of barium sulfate, calcium carbonate, and silica.

7. The resin filling material according to any one of claims 1 to 6, which is a resin filling material for at least one of a concave portion or a hole portion of a printed circuit board.

8. A cured product obtained by filling at least one of a concave portion and a hole portion of a printed wiring board with the resin filler according to any one of claims 1 to 7 and curing the resin filler.

9. A printed wiring board characterized by using the resin filler according to any one of claims 1 to 7.

Images