JP4765975B2 - Laminated board and printed wiring board using the same - Google Patents

Description

  The present invention relates to a laminate for a printed wiring board and a printed wiring board using the same.

  Printed wiring boards used for electronic devices, etc. are prepared by impregnating a base material such as a glass cloth with a varnish of a thermosetting resin such as an epoxy resin, and a predetermined number of the prepregs are stacked and further one or both sides thereof Manufactured by placing a metal foil, such as copper foil, and heating and pressurizing it to form a metal foil-clad laminate by forming a conductor pattern by processing the surface metal foil to a printed wiring Has been.

  Then, this printed wiring board is used as an inner circuit board, and a predetermined number of prepregs are stacked on the printed wiring board, and a metal foil is arranged on the outside thereof. A multilayer printed wiring board is manufactured by forming a conductor pattern by wiring and performing through-hole processing or the like as necessary.

  When mounting a semiconductor component, especially a large semiconductor component on the surface of such a printed wiring board, in order to increase the solder connection reliability (surface mounting reliability) on the surface, the linear expansion in the surface direction of the laminate is reduced. It is required to do. Further, in order to reduce the stress between the printed wiring board and the semiconductor component, a laminated board with reduced elasticity is required. Conventionally, it has been proposed to add rubber fine particles such as core-shell structure rubber particles coated with a shell phase compatible with an epoxy resin to the epoxy resin in order to keep the linear expansion in the plane direction of the laminate small (patent) References 1-3).

Moreover, in order to improve the reliability with respect to the thermal shock test of a printed wiring board, it is also necessary to suppress the linear expansion of the laminated board in the thickness direction. As a method for suppressing the linear expansion in the thickness direction of the laminate, it is known to add an inorganic filler such as silica to the epoxy resin. In addition, it has been proposed to blend core-shell structure rubber particles coated with a shell phase compatible with an epoxy resin into an epoxy resin and to use a phenol novolac resin as a curing agent (see Patent Document 4).
Japanese Patent Laid-Open No. 8-48001 JP 2000-158589 A JP 2003-246849 A JP 2006-143974 A

  However, no practically satisfactory means has been found in the past for solving the problem of suppressing the linear expansion in the thickness direction of the laminate. Further, for example, in the technique described in Patent Document 4 described above, in the examples illustrated in the examples, the core-shell structure rubber particles having a relatively low elastic modulus are used. When such rubber particles are used, Although it is effective in suppressing linear expansion, burrs occur on the end face when punching using a mold is performed on a printed wiring board produced using an epoxy resin composition containing this, There was a problem that mold workability deteriorated. That is, in Patent Document 4, no consideration is given to the Barcol hardness of the laminate.

  In addition, when a large amount of an inorganic filler is added in order to suppress the linear expansion in the thickness direction of the laminate, the linear expansion in the plane direction of the laminate is increased and surface mounting reliability cannot be obtained.

  The present invention has been made in view of the circumstances as described above, can suppress the linear expansion, has high surface mount reliability and thermal shock reliability, and is excellent in mold workability. It is an object to provide a laminated board and a printed wiring board using the laminated board.

  The present invention is characterized by the following in order to solve the above problems.

1stly, the laminated board of this invention is 16-40 mass with respect to the whole quantity of (A) epoxy resin, (B) the hardening | curing agent which has a phenol group, (C) epoxy resin (A), and a hardening | curing agent (B). % Of elastomer fine particles having a core-shell structure and compatible with the epoxy resin (A) and having rubber elasticity, and (D) 30 to 70% by mass with respect to the total amount of the epoxy resin (A) and the curing agent (B) A prepreg obtained by impregnating a base material with an epoxy resin composition containing the above inorganic filler and then heat-dried is laminated with a metal foil, and has a barcol hardness of 60 or more.

Second, the printed wiring board of the present invention is characterized by being formed by using the first laminate.

According to the first aspect of the invention, since a specific amount of elastomer fine particles compatible with an epoxy resin and having rubber elasticity and an inorganic filler are blended using a specific curing agent, both the surface direction and the thickness direction of the laminated plate are used. The printed circuit board produced using this has high surface mount reliability and thermal shock reliability. In addition, since the Barcol hardness is in a specific range by appropriately adjusting the elastic modulus of the elastomer fine particles, there is no burr on the end face during punching using a mold, surface mounting reliability and thermal shock reliability The improvement of moldability and the improvement of mold workability are compatible. Accordingly, a laminate for a printed wiring board having high surface mounting reliability and thermal shock reliability and excellent mold workability is provided.

According to the second aspect of the invention, since a specific amount of elastomer fine particles compatible with an epoxy resin and having rubber elasticity and an inorganic filler are blended using a specific curing agent, the surface direction and the thickness direction of the printed wiring board Both linear expansions can be reduced, and high surface mount reliability and thermal shock reliability can be obtained. In addition, since the Barcol hardness is in a specific range by appropriately adjusting the elastic modulus of the elastomer fine particles, there is no burr on the end face during punching using a mold, surface mounting reliability and thermal shock reliability The improvement of moldability and the improvement of mold workability are compatible. Therefore, a printed wiring board having high surface mounting reliability and thermal shock reliability and excellent mold workability is provided.

  The present invention has the features as described above, and an embodiment thereof will be described below.

  In the present invention, the epoxy resin (A) can be used without particular limitation as long as it has two or more epoxy groups in one molecule. Specific examples of such epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, biphenyl type epoxy resins, alicyclic epoxy resins, polyfunctional phenol diglycidyl ether compounds, polyfunctional alcohol diglycidyl ethers. Examples thereof include a compound, a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, a bisphenol A novolac type epoxy resin, and an epoxy resin obtained by halogenating these for flame retardancy. These epoxy resins can be used alone or in combination of two or more.

  In this invention, what has a phenol group is used as a hardening | curing agent (B). Specific examples include phenol novolak resins, and specific examples of such phenol novolak resins include phenol novolak resins, cresol novolak resins, bisphenol A novolak resins, and the like. These can be used alone or in combination of two or more. Further, these phenol novolak resins may be used in combination with a bifunctional or lower phenolic curing agent such as bisphenol A or phenol.

  By using such a curing agent, the linear expansion in the surface direction and the thickness direction of a laminate produced from a prepreg using an epoxy resin composition, compared to the case where an amine-based curing agent such as dicyandiamide is used. Can be kept low.

  The blending amount of the curing agent is preferably adjusted so that the equivalent ratio with respect to the epoxy resin is 0.5 to 1.5, particularly 0.8 to 1.2. If the equivalent ratio of the curing agent to the epoxy resin is less than 0.5, the epoxy resin composition may be insufficiently cured. If the equivalent ratio of the curing agent to the epoxy resin exceeds 1.5, the curing agent may remain unreacted, and performance such as heat resistance and impact resistance of the resulting laminate may be deteriorated.

  In the present invention, a curing accelerator may be used in combination with the above curing agent in order to accelerate the curing reaction. Any curing accelerator can be used without particular limitation as long as it accelerates the curing reaction of a normal epoxy resin. Specific examples thereof include imidazoles such as 2-methylimidazole and 2-phenylimidazole, Examples include tertiary amines such as ethylenediamine, and organic phosphines such as triphenylphosphine. These can be used alone or in combination of two or more. As for the compounding quantity of a hardening accelerator, 0.1-5.0 mass% is preferable with respect to all the resin components (an epoxy resin and a hardening | curing agent).

  In the present invention, the epoxy resin composition contains elastomer fine particles (C) that are compatible with the epoxy resin and have rubber elasticity. Here, “compatible with the epoxy resin” means that the elastomer fine particles (C) are uniformly dispersed in the epoxy resin.

  Thus, the elastomer fine particles are compatible with the epoxy resin, thereby reducing the linear expansion in the surface direction of the laminate obtained by using such an epoxy resin composition, and also reducing the linear expansion in the thickness direction. it can. Furthermore, when a printed wiring board produced using this laminated board is punched using a mold, it is possible to effectively prevent the generation of burrs on the end face.

  Preferred examples of the elastomer fine particles include those having a core-shell structure. Here, examples of the core-shell structure include a core phase of a rubber-like polymer having a relatively low Tg and a shell phase of a polymer having a higher Tg. The elastomer fine particles having such a core-shell structure can be obtained, for example, by seed polymerization of monomer mixtures having different compositions in a plurality of stages.

  Examples of the polymer constituting the shell phase include polymethyl methacrylate and polystyrene. Examples of the polymer constituting the core phase include acrylic polymers, silicone polymers, butadiene polymers, and isoprene polymers.

  In the present invention, the elastic modulus of the elastomer fine particles is appropriately adjusted so that the Barkol hardness of the laminate obtained by using the epoxy resin composition blended therewith is 60 or more. For example, the elastic modulus can be adjusted by the degree of crosslinking during the production of the elastomer fine particles. By adjusting the elastic modulus of the elastomer fine particles and setting the bar-cord hardness of the laminated board to 60 or more in this way, it is possible to effectively prevent the occurrence of burrs on the end face when punching using a mold on a printed wiring board. can do. On the other hand, if the elastic modulus of the elastomer fine particles is too small, burrs are generated on the end face when punching using a mold on the printed wiring board. However, if the elastic modulus of the elastomer fine particles is too high, the linear expansion in the plane direction of the laminate cannot be effectively suppressed.

  The elastomer fine particles are contained in the epoxy resin composition in an amount of 16 to 40% by mass with respect to the total amount of the epoxy resin and the curing agent. By blending elastomer fine particles within this range, using elastomer fine particles having an appropriate elastic modulus such that the Barcol hardness of the laminate is 60 or more, and further blending a specific amount of inorganic filler as described later, The linear expansion in the surface direction and the thickness direction of the laminated board can be suppressed to be small, and furthermore, the occurrence of burrs can be prevented when punching using a mold on the printed wiring board.

  When the content of the elastomer fine particles is less than 16% by mass with respect to the total amount of the epoxy resin and the curing agent, the linear expansion in the surface direction of the laminated board increases, and sufficient surface mounting reliability of the printed wiring board cannot be obtained. . When the content of the elastomer fine particles exceeds 40% by mass with respect to the total amount of the epoxy resin and the curing agent, the linear expansion in the thickness direction of the laminated board becomes large, and sufficient thermal shock reliability of the printed wiring board cannot be obtained.

  The size of the elastomer fine particles having a core-shell structure is preferably in the range of 0.1 to 10 μm in terms of particle diameter. Thereby, the elastomer fine particles are effectively dispersed in the epoxy resin composition, and the linear expansion in the surface direction and the thickness direction of the laminate can be further suppressed.

  In this invention, an inorganic filler (D) is mix | blended with an epoxy resin composition. By mix | blending an inorganic filler, the linear expansion of the thickness direction of the laminated board obtained using an epoxy resin composition can be reduced, and this laminated board can be toughened.

  Specific examples of the inorganic filler include silica, aluminum hydroxide, magnesium hydroxide, E glass powder, alumina, magnesium oxide, titanium dioxide, calcium silicate, calcium carbonate, clay, talc, and the like. It can be used alone or in combination of two or more. Moreover, you may use what surface-treated by coupling reaction etc. The size of the inorganic filler particles is not particularly limited, but those having an average particle size of 0.1 to 5 μm, for example, are used.

  The inorganic filler is contained in the epoxy resin composition in an amount of 30 to 70% by mass with respect to the total amount of the epoxy resin and the curing agent. By blending the inorganic filler within this range, the linear expansion in the thickness direction of the laminate can be kept small.

  When the content of the inorganic filler is less than 30% by mass with respect to the total amount of the epoxy resin and the curing agent, the linear expansion in the thickness direction of the laminated board increases, and sufficient thermal shock reliability of the printed wiring board is obtained. Absent. When the content of the inorganic filler exceeds 70% by mass with respect to the total amount of the epoxy resin and the curing agent, the linear expansion in the surface direction of the laminated board increases, and sufficient surface mounting reliability of the printed wiring board cannot be obtained. .

  In the present invention, the epoxy resin composition contains the above epoxy resin, curing agent, elastomer fine particles, inorganic filler, and, in some cases, a curing accelerator, and these are uniformly mixed with a mixer, blender, or the like. To be prepared as a varnish.

  The epoxy resin composition thus prepared is impregnated into a base material and then dried by heating to change the resin from an uncured state (A-stage) to a semi-cured state (B-stage). It is a prepreg.

  In producing the prepreg, an epoxy resin composition may be dissolved in an organic solvent to prepare a resin varnish, and the substrate may be impregnated with the resin varnish. For example, after the base material is immersed in the resin varnish and impregnated with the resin varnish, the epoxy resin composition in the base material is dried by heating at a temperature of about 120 to 180 ° C. The prepreg can be produced by removing the solvent and semi-curing to the B stage state.

  As the organic solvent, for example, toluene, xylene, benzene, dimethylformamide, ketones, alcohols, cellosolves and the like are used. Further, as the substrate, glass cloth, aramid cloth, polyester cloth, glass nonwoven fabric, paper or the like is used.

  The impregnation amount of the epoxy resin composition in the prepreg thus produced is not particularly limited, but is preferably in the range of 30 to 70% by mass.

  Then, a predetermined number of the above prepregs and further laminated metal foils are heated and heated under the conditions of, for example, a heating temperature of 150 to 300 ° C., a pressure of 0.98 to 6.0 MPa, and a time of 10 to 240 minutes. By pressing and molding, the resin is changed from a semi-cured state (B-stage) to a completely cured state (C-stage), and the laminate of the present invention can be manufactured. The metal foil is laminated on one side or both sides of the prepreg. As the metal foil, copper foil, aluminum foil or the like is used. The thickness of the metal foil is generally 3 to 105 μm, and particularly preferably 12 to 35 μm.

  Then, a printed wiring board is manufactured by forming a circuit pattern on a metal foil disposed on one or both sides of the laminated board by a subtractive method or the like, and performing processing such as forming a through hole as necessary.

  Further, a predetermined number of prepregs cut to a predetermined size are stacked on one side or both sides of an inner layer substrate (for example, a printed wiring board obtained as described above) on which a circuit pattern is formed in advance as an inner layer circuit, and the outer side thereof. A multilayer laminated board to be processed into a multilayer printed wiring board can be produced by stacking a metal foil such as a copper foil on the sheet and heating and pressing it to form a laminate. At this stage, the resin of the prepreg changes from a semi-cured state (B-stage) to a fully cured state (C-stage) to form an insulating layer.

  Then, a multilayer printed wiring board is manufactured by forming a circuit pattern by the subtractive method etc. in the metal foil arrange | positioned at the single side | surface or both surfaces of a multilayer laminated board.

  In the present invention, the Barcol hardness of the laminate and the printed wiring board produced as described above is 60 or more, preferably in the range of 60 to 65. By setting the Barcol hardness to 60 or more, it is possible to prevent the occurrence of burrs on the end face during punching using a mold. If the Barcol hardness is less than 60, burrs are generated on the end face during punching using a mold. In addition, when trying to obtain a material having a Barcol hardness of more than 65, the elastic modulus and content of the elastomer fine particles and the content of the inorganic filler often have to be out of the scope of the present invention. The surface mount reliability and thermal shock reliability of the printed wiring board cannot be obtained.

  Moreover, although the thermal expansion coefficient αY (Y is the longitudinal direction of the cross) in the plane direction based on JIS C 6481 of the laminated board and the printed wiring board manufactured as described above is 9.9 or less, depending on conditions. preferable. If αY exceeds 9.9, surface mount reliability cannot be obtained.

  Moreover, although the thermal expansion coefficient (alpha) Z of the thickness direction based on JISC6481 of the laminated board and printed wiring board which were manufactured as mentioned above is based also on conditions, 50 or less are preferable. If αZ exceeds 50, thermal shock reliability cannot be obtained.

  Therefore, an example will be shown below and will be described in more detail. Of course, the invention is not limited by the following examples.

(1) Compounding components In the following Examples and Comparative Examples, the following were used as epoxy resins, curing agents, elastomer fine particles, and inorganic fillers.
(A) Epoxy resin (a-1) “Epicron 153” manufactured by Dainippon Ink Co., Ltd. Brominated bisphenol A type epoxy resin Epoxy equivalent 390 to 410 g / eq Bromine content 46 to 50%)
(A-2) “EPON1031” manufactured by Japan Epoxy Resin Co., Ltd. Tetrafunctional epoxy resin Epoxy equivalent 195 to 230 g / eq
(A-3) “DER593” manufactured by Dow Chemical Co., Ltd. Epoxy equivalent 330-390 g / eq Bromine content 17-18 wt% Average molecular epoxy group content about 2 Epoxy resin containing both nitrogen and bromine in the molecule ( Oxazolidone ring included)
(A-4) “N690” manufactured by Dainippon Ink Co., Ltd. Cresol novolac epoxy resin Epoxy equivalent 190-240 g / eq Intramolecular average epoxy group content 4-6 Resin softening point about 95 ° C.
(B) Curing agent (b-1) “VH4170” manufactured by Dainippon Ink Co., Ltd. Bisphenol A novolac resin Hydroxyl equivalent weight 118 g / eq Resin softening point 105 ° C. Bifunctional bisphenol A content about 25%
(B ′) Curing accelerator (b′-1) “IM1000” manufactured by Nikko Materials Co., Ltd. Trialkoxysilyl type imidazole silane not containing secondary hydroxyl group (b′-2) Cyanation manufactured by Shikoku Kasei Kogyo Co., Ltd. 2-ethyl-4-methylimidazole (C) elastomer fine particles (c-1) “Staffyroid AC-3355” manufactured by Ganz Kasei Co., Ltd. Core-shell type in which the shell phase is polymethyl methacrylate and the core phase is a cross-linked acrylic polymer Fine particle (c-2) “Staphyroid AC-3816N” manufactured by Gantz Kasei Co., Ltd. Core-shell type fine particle (c-3) manufactured by Gantz Chemical Co., Ltd., whose shell phase is polymethyl methacrylate and whose core phase is a cross-linked acrylic polymer. Staphyloid AC-3832 "Core-shell type in which the shell phase is polymethyl methacrylate and the core phase is a cross-linked acrylic polymer Fine particles (c-4) “Torefill E-600” manufactured by Toray Dow Corning Silicone Co., Ltd. Silicone rubber fine particles In (c-1) to (c-3), the crosslinking density of the core phase is (c-1 )>(C-3)> (c-2), and the elastic modulus of the elastomer fine particles increases in this order.
(D) Inorganic filler (d-1) “SC2500-SEJ” manufactured by Admatechs Co., Ltd. Surface-treated silica Average particle size 0.4 to 0.6 μm (spherical)
(D-2) “C-303” manufactured by Sumitomo Chemical Co., Ltd. Aluminum hydroxide Average particle diameter of about 4 μm
(2) Preparation of resin varnish The resin varnish was prepared as follows. The epoxy resin and the curing agent shown in Table 1 and the solvent were weighed in a predetermined amount, stirred with a disper or the like, and homogenized. At this time, the amount of the solvent was adjusted so that the solid content (non-solvent component) such as an epoxy resin and a curing agent was 60 to 75% by mass to obtain a resin varnish. In addition, when mix | blending an inorganic filler, the predetermined compounding quantity was thrown in, Furthermore, after stirring for 1 hour with a disper, the resin varnish was obtained by disperse | distributing with a nanomill.
(3) Manufacture of prepreg As a base material, a glass cloth (“7628 type cloth” manufactured by Nitto Boseki Co., Ltd.) is used, and this glass cloth is impregnated with a resin varnish prepared by adding a solvent at room temperature. By heating at about 130-170 ° C. with a non-contact type heating unit, the solvent in the varnish was removed by drying, and the resin composition was semi-cured to prepare a prepreg. The amount of resin in the prepreg was adjusted to be 100 parts by mass of resin (resin 47 WT%) with respect to 106 parts by mass of the glass cloth.
(4) Manufacture of a copper-clad laminate A roughened surface of two copper foils (thickness 35 μm, JTC foil, manufactured by Nikko Gould Foil Co., Ltd.) was prepared from 8 prepregs (340 mm × 510 mm) prepared as described above. A copper-clad laminate was obtained by laminate molding at 180 ° C. and 30 kgf / cm ² for 90 minutes.
(5) Coefficient of thermal expansion For the copper-clad laminate produced as described above based on JIS C 6481, the thermal expansion coefficient αZ in the thickness direction before Tg and the heat in the plane direction are measured by the TMA method (Thermo-mechanical analysis). The expansion coefficient αY was measured (Y represents the longitudinal direction of the cloth).
(6) Barcol hardness Based on JIS K 7060, the copper-clad laminate produced as described above was etched to measure the Barcol hardness (applicable model: GYZJ 934-1).
(7) Evaluation of mold workability A plurality of circular opening patterns were formed on the copper foil of the above copper-clad laminate at regular intervals, and then a solder resist was applied to produce a mold processing substrate. . On this mold processing substrate, a hole of 5φ is formed at the position of the opening by punching (interval between the hole and the peripheral edge of the circular opening pattern: 1.0 mm), the cross section is observed, and burrs are made according to the following criteria. Evaluated.

The case where the burr after punching the laminated plate was less than 2.5 mm was judged as OK, and the case where it was 2.5 mm or more was judged as NG. A plurality of clearances for the mold to be used were set, and the above NG determination was performed at each clearance. The narrower the mold clearance, the better the punching performance, but the mold life is shortened. (Generally, when a 1.6 mm thick laminate is punched, the clearance is set to about 50 μm in consideration of the mold life.)
Punchability ○ OK with clearance of 50μm
Punchability △ ・ ・ ・ NG when clearance is 50μm, but OK when 10μm
Punchability x ... NG when clearance is 10μm
Punchability XX: NG with a clearance of 10 μm and generation of burrs of 10 mm or more <Examples 1 to 3>
Copper-clad laminates of Examples 1 to 3 were produced according to the above (1) to (4). With respect to these copper-clad laminates, the thermal expansion coefficient αZ in the thickness direction, the thermal expansion coefficient αY in the plane direction, and the Barcol hardness were measured, and the mold workability was further evaluated. The results are shown in Table 1. In addition, the compounding quantity of each component of the Example shown in Table 1 and a comparative example represents a mass part.
<Comparative Examples 1-8>
Copper-clad laminates of Comparative Examples 1 to 8 were produced according to the above (1) to (4). With respect to these copper-clad laminates, the thermal expansion coefficient αZ in the thickness direction, the thermal expansion coefficient αY in the plane direction, and the Barcol hardness were measured, and the mold workability was further evaluated. The results are shown in Table 1.

  As shown in Table 1, the compounding amount of the elastomer fine particles compatible with the epoxy resin is in the range of 16 to 40% by mass with respect to the total amount of the epoxy resin and the curing agent, and the compounding amount of the inorganic filler is While using the epoxy resin varnish which exists in the range of 30-70 mass% with respect to the whole quantity of an epoxy resin and a hardening | curing agent, adjusting the elastic modulus of elastomer fine particles made the Barcol hardness 60 or more of Examples 1-3 The thermal expansion coefficient αZ in the thickness direction and the thermal expansion coefficient αY in the surface direction are sufficiently small, and the thermal shock reliability and the surface mounting reliability are provided. Furthermore, almost no burrs were observed during punching using a mold.

  On the other hand, in Comparative Examples 1 and 2, since the elastomer fine particles having a low elastic modulus were used, the Barcol hardness was less than 60, and burrs were observed during punching using a mold.

  In Comparative Example 3, elastomer fine particles that were incompatible with the epoxy resin were used, and the Barcol hardness was less than 60, and a large amount of burrs was observed during punching using a mold. In Comparative Example 4, although the Barcol hardness was 60, since elastomer fine particles that were incompatible with the epoxy resin were used, burrs were observed during punching using a mold.

  In Comparative Example 5, the amount of the elastomer fine particles compatible with the epoxy resin was 15% by mass with respect to the total amount of the epoxy resin and the curing agent, the thermal expansion coefficient αY in the surface direction was increased, and the surface mounting reliability was lowered. .

  In Comparative Example 6, the blended amount of the elastomer fine particles compatible with the epoxy resin was 45% by mass with respect to the total amount of the epoxy resin and the curing agent, the thermal expansion coefficient αZ in the thickness direction was increased, and the thermal shock reliability was lowered. . Further, the bar call strength was 57, and burrs were observed during punching using a mold.

  In Comparative Example 7, the blending amount of the inorganic filler was 25% by mass with respect to the total amount of the epoxy resin and the curing agent, the thermal expansion coefficient αZ in the thickness direction was increased, and the thermal shock reliability was lowered.

  In Comparative Example 8, the blending amount of the inorganic filler was 80% by mass with respect to the total amount of the epoxy resin and the curing agent, the thermal expansion coefficient αY in the surface direction was increased, and the surface mounting reliability was lowered.

Claims (2)

(A) Epoxy resin, (B) Curing agent having phenol group, (C) Epoxy resin having a core-shell structure of 16 to 40% by mass with respect to the total amount of epoxy resin (A) and curing agent (B) ( An epoxy resin composition containing elastomer fine particles compatible with A) and having rubber elasticity, and (D) 30 to 70% by mass of an inorganic filler based on the total amount of the epoxy resin (A) and the curing agent (B). A laminated board characterized by being obtained by laminating a prepreg obtained by impregnating a substrate with a material and then drying by heating together with a metal foil, and having a Barcol hardness of 60 or more.   A printed wiring board formed using the laminated board according to claim 1.