JP2014208751A - Epoxy resin composition, composition for filling gap, and printed wiring board using the same - Google Patents

Abstract

The present invention provides an epoxy resin composition excellent in polishing stability and heat resistance capable of greatly reducing the occurrence of voids and cracks, and a composition for filling a hole, and a printed wiring using the same. Provide a board. SOLUTION: It comprises (A) an epoxy resin, (B) an imidazole compound, (C) a boric acid ester compound, and (D) an inorganic filler. The (B) imidazole compound is preferably a non-latent type, and the blending amount of the (B) imidazole compound is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the (A) epoxy resin. . [Selection] Figure 1

Description

  The present invention relates to an epoxy resin composition (hereinafter, also simply referred to as “resin composition”), a composition for filling a hole and a printed wiring board using these, and more specifically, it has superior storage stability than conventional ones, voids and The present invention relates to an epoxy resin composition excellent in abrasiveness and heat resistance capable of greatly reducing the occurrence of cracks, a composition for filling a hole, and a printed wiring board using these.

  In recent years, the printed wiring board pattern has become thinner and the mounting area has been reduced, and the printed wiring board has been made lighter, thinner, and smaller in order to cope with the downsizing and higher functionality of equipment equipped with the printed wiring board. It is desired. Therefore, the printed wiring board forms a resin insulation layer on the top and bottom of the core substrate, and after forming the necessary conductor circuit, further forms the resin insulation layer, to the build-up method of the method of forming the conductor circuit, In addition, the mounting components are evolving into area array types such as BGA (ball grid array) and LGA (land grid array). Under such circumstances, it is desired to develop a permanent hole filling composition excellent in filling properties, polishing properties, cured product characteristics, and the like for filling holes such as through holes and via holes.

  In general, thermosetting epoxy resin compositions are widely used as permanent hole filling compositions for printed wiring boards because their cured products have excellent mechanical, electrical, and chemical properties and good adhesion. It has been. Permanent hole filling processing of a printed wiring board using such a resin composition generally includes a step of filling the hole portion of the printed wiring board with an epoxy resin composition and a state in which the filled composition can be heated and polished. It consists of a step of pre-curing, a step of polishing and removing a portion protruding from the surface of the hole of the pre-cured resin composition, and a step of further heating and pre-curing the pre-cured resin composition.

  In the permanent hole filling process of the printed wiring board, voids are inevitably generated due to air entrainment or the like when filling the resin composition into holes such as through holes and via holes. This void is difficult to remove completely even if pre-curing or main curing is performed, and cannot be eliminated. Such a phenomenon becomes more prominent as the depth of the hole is deeper (in the case of a through hole, the core substrate is thicker) and the viscosity of the resin composition is higher. Moreover, in the permanent hole filling process of the printed wiring board, there is a problem that cracks occur during preliminary curing.

  Furthermore, in the past, imidazole compounds have been widely used as curing agents for epoxy resin compositions in epoxy resin compositions used for hole filling of printed wiring boards. When an imidazole compound is used as a curing agent, there is an advantage that the resin composition can be cured in a short time at a low temperature, but on the other hand, there is a problem that the storage stability of the resin composition is poor and the resin composition cannot be stored for a long time. Had. As a technique for improving the storage stability of an epoxy resin composition, for example, Patent Document 1 proposes to use a microencapsulated amine-based curing agent that is a latent curing agent as a curing agent for an epoxy resin composition. Has been.

JP 2004-115729 A

  The latent curing agent is excellent in the storage stability of the epoxy resin composition because the curing reaction with the epoxy resin does not easily proceed. However, in order to obtain the effect as a curing agent, the blending amount with respect to the epoxy resin must be increased. When the blending amount of the latent curing agent is increased, the viscosity of the epoxy resin composition is increased, and voids are generated due to air entrainment or the like at the time of filling a printed wiring board. Thus, it has been difficult to simultaneously improve the storage stability of the epoxy resin composition and the occurrence of voids and cracks. Moreover, the heat resistance of the obtained cured product was not sufficient.

  Accordingly, an object of the present invention is to provide an epoxy resin composition excellent in abrasive stability and heat resistance capable of greatly reducing the occurrence of voids and cracks, and a composition for filling a hole, and these, which are superior in storage stability than in the past. It is in providing the printed wiring board using the.

  As a result of diligent studies to solve the above problems, the present inventor has added a boric acid ester compound to an epoxy resin composition containing an imidazole compound as a curing agent. It has been found that the above-mentioned problems can be solved by mixing a boric acid ester compound with the product, and the present invention has been completed.

  That is, the epoxy resin composition of the present invention comprises (A) an epoxy resin, (B) an imidazole compound, (C) a boric acid ester compound, and (D) an inorganic filler. To do.

  In the epoxy resin composition of the present invention, the (B) imidazole compound is preferably non-latent, and the amount of the (B) imidazole compound is 100 parts by mass of the (A) epoxy resin. It is preferable that it is 1-20 mass parts with respect to it. Furthermore, in the epoxy resin composition of the present invention, the difference between the initial gel time and the gel time after storage at 30 ° C. for 20 days after production is preferably within 10%. Since the epoxy resin composition of the present invention has excellent characteristics as described above, it is suitable for filling concave portions and through holes of printed wiring boards.

  Moreover, the hole filling and filling composition of the present invention contains a borate ester compound.

  Furthermore, the printed wiring board of the present invention is characterized in that the epoxy resin composition of the present invention is used or the hole filling and filling composition of the present invention is used.

  According to the present invention, the epoxy resin composition, the filling composition for filling holes, and the epoxy resin composition excellent in abrasiveness and heat resistance, which are superior in storage stability and can greatly reduce the occurrence of voids and cracks, are used. A printed wiring board can be provided. Moreover, the epoxy resin composition and the filling composition for filling a hole of the present invention can be cured at a low temperature and in a short time while being excellent in storage stability by containing a borate ester compound. Furthermore, since the epoxy resin composition and the filling composition for filling a hole of the present invention are excellent in storage stability, they are excellent in one-part property that all components can be stored together.

It is a schematic sectional drawing which shows an example of a part of manufacturing process of the printed wiring board of this invention. It is a schematic sectional drawing which shows an example of the process after the manufacturing process of the printed wiring board of this invention shown in FIG. It is a schematic sectional drawing which shows the other example of the manufacturing method of the printed wiring board of this invention.

Hereinafter, embodiments of the present invention will be described in detail.
The epoxy resin composition of the present invention comprises (A) an epoxy resin, (B) an imidazole compound, (C) a boric acid ester compound, and (D) an inorganic filler. By adding the (C) boric acid ester compound to the epoxy resin composition, the (C) boric acid ester compound is coordinated to the amino group that is the active group of the (B) imidazole compound, and the curing reaction of the resin composition Therefore, it is considered that the resin composition can be stored for a long time.

  Moreover, by adding the (C) borate compound to the epoxy resin composition, the gel time can be delayed to the extent that it does not affect the curing time of the resin composition. As a result, it is possible to maintain a low-viscosity state for a long time when the resin composition is cured, which makes it easier for bubbles in the resin composition to escape during hole-filling processing of printed wiring boards and suppress the occurrence of voids and cracks. can do.

  Further, conventionally, preliminary curing at a low temperature has been performed in order to sufficiently remove air in the resin composition. However, since the epoxy resin composition of the present invention has a longer gel time than a conventional epoxy resin composition, air can be removed from the resin composition without pre-curing. Therefore, the preliminary curing step can be omitted. Hereinafter, each component of the epoxy resin composition of the present invention will be described in detail.

<(A) Epoxy resin>
A known epoxy resin can be used for the epoxy resin composition of the present invention. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A Novolac epoxy resin, biphenyl epoxy resin, naphthol epoxy resin, naphthalene epoxy resin, dicyclopentadiene epoxy resin, triphenylmethane epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, phosphorus-containing Epoxy resin, anthracene type epoxy resin, norbornene type epoxy resin, adamantane type epoxy resin, fluorene type epoxy resin, aminophenol type epoxy resin, aminocresol Epoxy resins, alkylphenol type epoxy resin or the like.

  When using the resin composition of this invention as a hole-filling material of a printed wiring board, since it is preferable that it is solventless, a liquid epoxy resin is suitable. From such a viewpoint, in the resin composition of the present invention, a bisphenol A type, bisphenol F type, aminophenol type, or phenol novolac type epoxy resin can be suitably used. In addition, in the resin composition of this invention, these epoxy resins may be used independently or may use 2 or more types together. Further, when a solid epoxy resin is used instead of a liquid epoxy resin, an imidazole compound, a borate ester compound and an inorganic filler described later may be dispersed in the solid epoxy resin using a solvent.

  (A) As a commercial product of epoxy resin, for example, as bisphenol A type liquid epoxy resin, 828 manufactured by Mitsubishi Chemical Co., Ltd., YD127 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., as bisphenol F type liquid epoxy resin, Mitsubishi Chemical 807 manufactured by NSSMC, YD170 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., aminophenol type liquid epoxy resin (paraaminophenol type liquid epoxy resin), jER-630 manufactured by Mitsubishi Chemical Corporation, manufactured by Sumitomo Chemical Co., Ltd. ELM-100 and the like.

<(B) Imidazole compound>
A known imidazole compound can be used for the epoxy resin composition of the present invention. In the epoxy resin composition of the present invention, the imidazole compound is preferably a non-latent type. Here, the latent imidazole compound refers to, for example, a reaction product of an epoxy resin and imidazole. Examples of the (B) imidazole compound of the present invention include 2-methylimidazole, 4-methyl-2-ethylimidazole, 2-phenylimidazole, 4-methyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 2 -Ethylimidazole, 2-isopropylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole and the like can be mentioned.

  In particular, in the resin composition of the present invention, among the imidazole compounds, imidazole compounds that are not microencapsulated are preferable. This is because an imidazole compound that is not microencapsulated requires only a small amount of addition to the resin composition and can prevent voids due to an increase in the viscosity of the resin composition. In addition, in the resin composition of this invention, an imidazole compound may be used independently or may use 2 or more types together.

  (B) Examples of commercially available imidazole compounds include imidazoles such as 2E4MZ, C11Z, C17Z, and 2PZ, and AZINE (azine) compounds of imidazoles such as 2MZ-A and 2E4MZ-A, 2MZ-OK, and 2PZ-OK. Imidazole hydroxymethyl compounds such as isocyanurate of imidazole such as 2PHZ and 2P4MHZ (all of which are manufactured by Shikoku Kasei Kogyo Co., Ltd.).

  In the resin composition of this invention, it is preferable that the addition amount of (B) imidazole compound is 1-20 mass parts with respect to 100 mass parts of (A) epoxy resins, and it is 1-10 mass parts. More preferred. (B) If the addition amount of the imidazole compound is 1 part by mass or more, the curing rate of the resin composition can be increased, and as a result of sufficient curing of the composition in the deep part of the hole, cracks are less likely to occur. preferable. On the other hand, when the amount is 20 parts by mass or less, storage stability is improved, the preliminary curing rate of the resin composition is decreased, and voids are less likely to remain in the cured product. More preferably, it is 5 to 15 parts by mass.

<(C) Boric acid ester compound>
A known boric acid ester compound can be used in the epoxy resin composition of the present invention. For example, triphenyl borate or cyclic borate having low volatility can be used. A cyclic borate compound is preferred. The cyclic borate ester compound is a compound in which boron is contained in a cyclic structure, and 2,2′-oxybis (5,5′-dimethyl-1,3,2-oxaborinane) is particularly preferable. Examples of boric acid ester compounds include trimethyl borate, triethyl borate, tripropyl borate, tributyl borate, and the like other than triphenyl borate and cyclic borate compounds. Since the compound has high volatility, the effect may not be sufficient for the storage stability of the composition particularly at high temperatures. In addition, in the resin composition of this invention, these boric acid ester compounds may be used independently, or may use 2 or more types together.

  (C) Examples of commercially available boric acid ester compounds include high boron BC1, high boron BC2, high boron BC3, high boron BCN (all of which are manufactured by Boron International Co., Ltd.), cure duct L-07N (Shikoku Kasei Kogyo Co., Ltd.) )) And the like.

  In the resin composition of this invention, it is preferable that the addition amount of (C) boric acid ester compound is 0.01-5 mass parts with respect to 100 mass parts of (A) epoxy resins, and 0.01-3. More preferably, it is part by mass. It is because it will become difficult to inhibit the hardening reaction of (A) epoxy resin and (B) imidazole compound if the addition amount of (C) boric acid ester compound is 5 mass parts or less. On the other hand, if it is 0.01 mass part or more, sufficient long-term storage stability is obtained. More preferably, it is 0.05-1 mass part.

<(D) Inorganic filler>
For the epoxy resin composition of the present invention, known inorganic fillers used in ordinary resin compositions can be used. Specifically, for example, silica, barium sulfate, calcium carbonate, silicon nitride, aluminum nitride, boron nitride, alumina, magnesium oxide, aluminum hydroxide, magnesium hydroxide, titanium oxide, mica, talc, Neuburg silica, organic bentonite Nonmetal fillers such as copper, metal fillers such as copper, gold, silver, palladium, and silicon can be used. In the resin composition of this invention, these inorganic fillers may be used independently or may use 2 or more types together.

  Of these, silica and calcium carbonate, which are excellent in low hygroscopicity and low volume expansibility, are preferable. Silica may be either amorphous or crystalline, or a mixture thereof. In particular, amorphous (fused) silica is preferred. The calcium carbonate may be either natural heavy calcium carbonate or synthetic precipitated calcium carbonate. When using the resin composition of this invention as a hole-filling material of a printed wiring board, the calcium carbonate which is excellent in abrasiveness is suitable.

  Examples of the shape of such an inorganic filler include a spherical shape, a needle shape, a plate shape, a scale shape, a hollow shape, an indefinite shape, a hexagonal shape, a cubic shape, and a flake shape. preferable.

  The average particle size of these inorganic fillers is preferably 0.1 to 25 μm. When the average particle size is 0.1 μm or more, the specific surface area is small, and the filler is favorably dispersed due to the effect of agglomeration between the fillers, and the filling amount of the filler can be easily increased. On the other hand, if it is 25 μm or less, when the resin composition of the present invention is used as a hole filling material for a printed wiring board, the filling property to the hole of the printed wiring board is improved, and further, a conductor layer is formed in the filled portion. This has the effect of improving smoothness. More preferably, it is 1-10 micrometers. Here, the average particle size means an average primary particle size. The average particle diameter (D50) can be measured by a laser diffraction / scattering method.

  In the resin composition of this invention, it is preferable that (D) inorganic filler is contained by 40 to 90 mass% in the whole composition. (D) If the addition amount of an inorganic filler is 40 mass% or more, the hardened | cured material obtained shows sufficient low expansibility, and exhibits polishability and adhesiveness. On the other hand, when the amount is 95% by mass or less, liquid paste is easily generated, and printability, hole filling and filling properties, and the like are obtained. More preferably, it is 50-75 mass%.

<Others>
The epoxy resin composition of the present invention contains (A) an epoxy resin, (B) an imidazole compound, (C) a boric acid ester compound, and (D) an inorganic filler. Depending on the, other known additives may be added. For example, phthalocyanine blue, phthalocyanine green, iodin green, disazo yellow, crystal violet, titanium oxide, carbon black, naphthalene black and other known and commonly used colorants, hydroquinone, hydroquinone to provide storage stability during storage Known and commonly used thermal polymerization inhibitors such as monomethyl ether, tert-butylcatechol, pyrogallol and phenothiazine, known and commonly used thickeners or thixotropic agents such as clay, kaolin, organic bentonite and montmorillonite, silicones, fluorines and polymers Conventional additives such as an antifoaming agent and / or a leveling agent such as an adhesion imparting agent such as an imidazole-based, thiazole-based, triazole-based, and silane coupling agent can be added. In particular, when organic bentonite is used, a portion protruding from the surface of the hole is easily formed in a protruding state that can be easily polished and removed, and is excellent in polishing properties.

  When the resin composition of the present invention is used as a filling material for a printed wiring board, a liquid epoxy resin is suitable. However, as described above, a solid epoxy resin may be dissolved in a solvent and used. In this case, ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents and the like can be used as the solvent. Specifically, ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether , Glycol ethers such as dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, S such as propylene glycol butyl ether acetate, methyl lactate, ethyl lactate, butyl lactate Examples include alcohols such as ethanol, propanol, ethylene glycol, and propylene glycol; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. it can. These solvents may be used alone or in combination of two or more. In addition, what is necessary is just to determine the compounding quantity of a solvent suitably based on workability | operativity etc. in the range in which the effect of this invention is acquired.

  In the epoxy resin composition of the present invention, in order to improve the storage stability and the occurrence of voids and cracks than before, it is preferably stored at the initial gel time and at 30 ° C. for 20 days from the production. What is necessary is just to determine suitably the addition amount of each component of an epoxy resin composition within the said range so that the difference with a later gel time is less than 10%, and this characteristic is acquired. In the resin composition of the present invention, the difference in gel time is more preferably within 5%. An epoxy resin composition that satisfies such requirements is excellent in storage stability because there is little difference in gel time. Moreover, since gel time can be made longer than the conventional composition, generation | occurrence | production of a crack and a void can be suppressed. The epoxy resin composition of the present invention has a long gel time but can be sufficiently cured by heating.

  The epoxy resin composition of the present invention can be easily applied to holes such as via holes and through holes of printed wiring boards by using conventionally employed methods such as screen printing, roll coating, and die coating. Can be filled. Next, for example, the resin composition is cured by heating at about 120 to 180 ° C. for about 30 to 90 minutes. Unnecessary portions protruding from the substrate surface of the resin composition thus cured can be easily removed by physical polishing and can be made flat. The physical polishing can be performed by a known method that has been conventionally performed.

  In addition, the epoxy resin composition of the present invention is not only used as a permanent hole filling composition for printed wiring boards, but also by taking advantage of the excellent characteristics as described above, solder resist, interlayer insulating material, coverlay, solder dam, IC package It can be suitably used for other applications such as a sealing material.

Next, the hole filling composition of the present invention will be described.
The composition for filling a hole of the present invention contains a borate ester compound. By filling boric acid ester with the composition for filling in hole filling, the composition for filling in hole filling with excellent polishing stability and heat resistance, which is superior in storage stability and can greatly reduce the occurrence of voids and cracks. It can be. In the present invention, it is important to mix a boric acid ester with a filler composition used for filling a hole in a printed wiring board or the like, and the filler composition used for filling a hole in a printed wiring board or the like A known one can be used.

Next, the printed wiring board of the present invention will be described.
The printed wiring board of the present invention is the one using the epoxy resin composition of the present invention, preferably used as a filling material for holes such as through holes such as through holes and via holes in printed wiring boards. It is. Hereinafter, the manufacturing method of the printed wiring board of this invention is demonstrated in detail, referring FIGS.

<Formation of through holes>
FIG. 1 is a schematic cross-sectional view showing an example of a part of the manufacturing process of the printed wiring board of the present invention. First, as shown in FIG. 1A, a through hole is formed in a substrate 1 laminated with a copper foil 2 with a drill or the like, and electroless plating is performed on the wall surface of the through hole and the surface of the copper foil 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, a fluororesin substrate, a copper-clad laminate of these resin substrates, a ceramic substrate, a metal substrate, or the like can be used. In the case of a poorly plated substrate such as a fluororesin substrate, surface modification such as a pretreatment agent made of organometallic sodium or plasma treatment is performed. Next, electrolytic plating is performed for thickening, and a plating film 4a is formed on the surface of the substrate 1 and the inner wall of the through hole 3 as shown in FIG. As this electrolytic plating, copper plating is preferable.

<Filling holes>
The through hole 3 formed in the substrate 1 is filled with the resin composition 5 of the present invention as shown in FIG. Specifically, a mask having an opening in the through-hole 3 portion is placed on the substrate 1 and can be easily filled into the through-hole 3 by application by a printing method or the like, a dot printing method, or the like. Next, after the resin composition 5 is cured by heating at about 120 to 180 ° C. for about 30 to 90 minutes, the resin composition 5 protruding from the through hole 3 is unnecessary as shown in FIG. The portion is removed by polishing and flattened. Polishing can be performed by belt sander or buffing.

<Formation of conductor circuit layer>
A plating film 4b is formed on the surface of the substrate 1 in which the through holes 3 have been filled, as shown in FIG. Thereafter, an etching resist 6 is formed as shown in FIG. 1F, and the non-resist forming portion is etched. Next, the etching resist 6 is peeled to form a conductor circuit layer 7a as shown in FIG.

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

<Formation of via holes>
Next, as shown in FIG. 2A, an opening 9a is provided in the interlayer resin insulating layer 8a. The opening 9a is perforated by exposure and development processing when the interlayer resin insulating layer 8a is made of a photosensitive resin, and laser light when it is made of a thermosetting resin or a thermoplastic resin. When the opening 9a is provided by laser light, desmear processing may be performed.

  Next, as shown in FIG. 2B, a plating film 4c is formed on the entire surface. Then, as shown in FIG. 2C, a plating resist layer 10 is formed on the plating film 4c. The plating resist layer 10 is preferably formed by laminating a photosensitive dry film, exposing and developing. Further, electrolytic plating is performed to thicken the conductor circuit portion, and an electrolytic plating film 4d is formed as shown in FIG.

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

  FIG. 3 is a schematic cross-sectional view showing another example of the method for producing a printed wiring board of the present invention. After finishing the core substrate manufacturing process as shown in FIG. 1D, when the conductor layers on both surfaces of the core substrate 1 are etched in a predetermined pattern, as shown in FIG. A first conductor circuit layer 7b having a predetermined pattern on both sides is formed, and lands 12 are simultaneously formed on a part of the conductor circuit layer 7b connected to the through hole 3.

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

  And as shown in FIG.3 (c), the soldering resist layer 13 is formed on each resin insulation layer 8b and the 2nd conductor circuit layer 7c, and the upper soldering resist layer 13 penetrates this, and Solder bumps 14 standing from the surface of the conductor circuit layer are formed. The conductor circuit layer 7c exposed from the opening 9b formed between the lower solder resist layers 13 can be plated with Au and Ni to obtain a multilayer wiring board used as a connection terminal.

Hereinafter, the present invention will be described in more detail with reference to examples.
Epoxy resin compositions were prepared with the formulations (parts by mass) shown in Tables 1 to 3 below. About each obtained resin composition, the viscosity and gel time after storing it for 20 days at the initial stage and 30 degreeC were measured in the following procedure. After that, each resin composition stored for 20 days at initial and 30 ° C. on a glass epoxy substrate (plate thickness 1.6 mm, through hole diameter 0.3 mm) on which through holes had been formed in advance by panel plating was screen-printed. Filled in. This was put into a hot air circulation type drying furnace and held at 150 ° C. for 30 minutes to prepare an evaluation sample. For each of the obtained evaluation samples, cracks, residual voids, polishing properties, and solder heat resistance were evaluated by the following methods. The obtained results are shown in Tables 4-6.

<Viscosity>
0.2 mL of each resin composition was sampled, and the viscosity was determined at 30 ° C. and a rotation speed of 5 rpm for 30 seconds using a cone plate viscometer (TV-30: manufactured by Toki Sangyo Co., Ltd.).

<Geltime>
It measured with the gel tester based on the hot plate method of JISC2105. The time until the torque when the rotating rod was rotated in 0.5 mL of the sample held at a measurement temperature of 150 ° C. reached 30% of the maximum torque was defined as the gel time. The difference in gel time was calculated by the following formula.
Difference in gel time (%) = {(initial gel time−gel time after 30 days at 30 ° C.) / Initial gel time} × 100

<Void>
Each evaluation sample was cut at the through-hole portion, and the cross-section was observed with an optical microscope to count the number of voids generated in 100 through-holes. The evaluation criteria are as follows.
〇 ・ ・ ・ 0 △ ・ ・ ・ 1 to 5 × ・ ・ ・ 6 or more

<Crack>
Each evaluation sample was cut at the through hole portion, and the cross section was observed with an optical microscope to count the number of occurrences of cracks in 100 through holes. The evaluation criteria are as follows.
〇 ・ ・ ・ 0 △ ・ ・ ・ 1 to 5 × ・ ・ ・ 6 or more

<Abrasiveness>
Each evaluation sample was physically polished by a polishing machine with a resin polishing buff uniaxial shaft corresponding to # 320. At that time, the number of passes until the resin was completely removed was compared.

<Solder heat resistance>
Each evaluation sample was physically polished by a polishing machine with a resin polishing buff uniaxial shaft corresponding to # 320. Thereafter, it was immersed in a solder liquid at 288 ° C. for 3 seconds for 10 seconds, and then allowed to cool to room temperature. Subsequently, it cut | disconnected by the through hole part, the cross section was observed with the optical microscope, and the generation | occurrence | production number of the crack in 100 through holes was counted. The evaluation criteria are as follows.
〇 ・ ・ ・ 0 △ ・ ・ ・ 1 to 5 × ・ ・ ・ 6 or more

※１：新日鉄住金化学（株）製ＹＤ１２７
※２：新日鉄住金化学（株）製ＹＤＦ１７０
※３：住友化学（株）製ＥＬＭ−１００
※４：ダウケミカル(株)製 ＤＥＮ-４３１
※５：２，２’−オキシビス（５，５’−ジメチル−１，３，２−オキサボリナン）
※６：四国化成工業（株）製２ＭＺ−Ａ
※７：四国化成工業（株）製２Ｐ４ＭＨＺ
※８：旭化成イーマテリアルズ（株）製ノバキュアＨ１０３９４１ＨＰ
※９：日本化薬（株）製カヤハードＡ−Ａ
※１０：備北粉化工業（株）製ソフトン１８００（平均粒径：１．２５μｍ）
※１１：（株）アドマテック製ＳＯ−Ｃ５（平均粒径：１．６μｍ）
※１２：白石工業（株）製オルベン
※１３：信越化学工業（株）製ＫＳ−６６

* 1: YD127 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.
* 2: YDF170 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.
* 3: ELM-100 manufactured by Sumitomo Chemical Co., Ltd.
* 4: DEN-431 manufactured by Dow Chemical Co., Ltd.
* 5: 2,2′-oxybis (5,5′-dimethyl-1,3,2-oxaborinane)
* 6: Shikoku Kasei Kogyo Co., Ltd. 2MZ-A
* 7: Shikoku Kasei Kogyo Co., Ltd. 2P4MHZ
* 8: NovaCure H103941HP manufactured by Asahi Kasei E-Materials Co., Ltd.
* 9: Kayahard A-A manufactured by Nippon Kayaku Co., Ltd.
* 10: Softon 1800 manufactured by Bihoku Flour Industry Co., Ltd. (average particle size: 1.25 μm)
* 11: Admatech Co., Ltd. SO-C5 (average particle size: 1.6 μm)
* 12: Olven manufactured by Shiraishi Kogyo Co., Ltd. * 13: KS-66 manufactured by Shin-Etsu Chemical Co., Ltd.

  As described above, Tables 1 to 6 show that the resin composition of the present invention can remarkably suppress the generation of voids and cracks when used as a hole filling material for printed wiring boards. Moreover, it turns out that the resin composition of this invention is excellent also in storage stability and heat resistance.

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Copper foil 3 Through hole 4 Plating film 5 Resin composition
6 Etching resist 7 Conductor circuit layer 8 Interlayer resin insulating layer 9 Opening 10 Plating resist layer 11 Via hole 12 Land 13 Solder resist layer 14 Solder bump

Claims (8)

  An epoxy resin composition comprising (A) an epoxy resin, (B) an imidazole compound, (C) a borate compound, and (D) an inorganic filler.   The epoxy resin composition according to claim 1, wherein the (B) imidazole compound is non-latent.   The epoxy resin composition according to claim 1 or 2, wherein a blending amount of the (B) imidazole compound is 1 to 20 parts by mass with respect to 100 parts by mass of the (A) epoxy resin.   The epoxy resin composition according to any one of claims 1 to 3, wherein a difference between an initial gel time and a gel time after storage at 30 ° C for 20 days from production is within 10%.   The epoxy resin composition according to any one of claims 1 to 4, which is used for filling at least one of a concave portion and a through hole of a printed wiring board.   A composition for filling a hole, which comprises a borate ester compound.   A printed wiring board comprising the epoxy resin composition according to any one of claims 1 to 5.   A printed wiring board comprising the composition for filling a hole according to claim 6.

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