JP4830748B2 - Flame retardant epoxy resin composition, resin film, prepreg and multilayer printed wiring board - Google Patents

Description

  The present invention relates to an epoxy resin composition containing substantially no halogen, and particularly to an epoxy resin composition suitably used as an insulating material for a printed wiring board or the like by a build-up method using a plating process. Moreover, it is related with the prepreg, resin film, and multilayer printed wiring board using such an epoxy resin composition.

  In recent years, in the production of printed wiring boards, build-up methods using an additive method for forming circuits by plating processes on board materials made of epoxy resin cured products have been widely adopted due to demands for miniaturization and high-density mounting. . In the plating process, the surface of the substrate is usually roughened with an oxidizing agent such as potassium permanganate in order to improve the adhesion of plating (for example, Patent Document 1).

And in order to raise the degree of roughening by such a roughening process, the method of making the epoxy resin hardened material contain the rubber component which can be preferentially melt | dissolved with an oxidizing agent is known (for example, patent document 2). . However, when an epoxy resin cured product containing a rubber component is used as the substrate material, the thermal expansion coefficient of the rubber component is relatively large, so that the thermal expansion coefficient of the substrate is increased. Therefore, when a circuit is formed on such a substrate by a plating process, there is a problem that a crack may occur in the plating due to expansion or contraction of the substrate when it is subjected to a cooling test, which may cause poor conduction. . Moreover, a rubber component is comparatively flammable, and an epoxy resin cured product containing such a rubber component is poor in flame retardancy. For this reason, halogenated flame retardants such as brominated flame retardants having excellent flame retardancy are usually blended with such cured epoxy resins. However, a cured epoxy resin containing a halogen-based flame retardant may generate harmful substances such as hydrogen halide during combustion. Hazardous substances such as hydrogen halide have the disadvantage of adversely affecting the human body and the natural environment.
JP-A-7-304933 JP-A-11-1547

  In view of the above problems, the present invention provides a flame-retardant epoxy resin composition having high plating adhesion without using a rubber component and having sufficient flame retardancy even without containing a halogen-based flame retardant. It is an object to provide an article, a resin film, a prepreg, and a multilayer printed wiring board.

  As a result of intensive studies to solve the above problems, the present inventor has found that the above problems can be solved by the following means.

  That is, the flame retardant epoxy resin composition of the present invention comprises (A) a bisphenol A type epoxy resin, (B) a modified phenol novolac type epoxy resin having a phosphaphenanthrene structure in the molecule, and (C) in the molecule. A phenolic novolak curing agent having a triazine ring is contained, and the mass ratio (B) / (A) of the component (B) to the component (A) is 0.5 to 2. With such a configuration, it is possible to obtain a flame retardant epoxy resin composition having high plating adhesion and sufficient flame retardancy without using a halogen flame retardant. In addition, when the mass ratio (B) / (A) is 0.5 to 2, high plating adhesion can be maintained.

  The bisphenol A type epoxy resin (A) is preferably a bisphenol A type epoxy resin (A-1) having a phosphorus atom in the molecule. Thus, when using the bisphenol A type epoxy resin (A-1) which has a phosphorus atom in a molecule | numerator, still higher flame retardance and plating adhesiveness can be obtained.

  The bisphenol A type epoxy resin (A-1) having a phosphorus atom in the molecule is preferably a bisphenol A type epoxy resin (A-2) having a phosphaphenanthrene structure in the molecule. Thus, by using the bisphenol A type epoxy resin (A-2) having a phosphaphenanthrene structure in the molecule, higher flame retardancy and plating adhesion can be obtained.

  In addition, when the flame retardant epoxy resin composition further contains (D) an inorganic filler, the expansion or contraction of the substrate when subjected to a cold test can be reduced. Increased reliability.

  Moreover, the resin film of this invention is formed from the said flame-retardant epoxy resin composition. If such a resin film is used, a resin film having high flame retardancy can be obtained without containing a halogen-based flame retardant. When such a resin film is used in the production of a multilayer printed wiring board, a resin insulation layer having high plating adhesion and high flame retardancy without using a halogen flame retardant is formed. be able to.

  In addition, the prepreg of the present invention is formed by impregnating a sheet-like base material with the varnish of the flame retardant epoxy resin composition and drying it. When such a prepreg is used, a prepreg having high flame retardancy can be obtained in the production of a multilayer printed wiring board without containing a halogen-based flame retardant. And, when such a prepreg is used for the production of a multilayer printed wiring board, a resin insulating layer having high plating adhesion and having high flame retardancy without using a halogen flame retardant is formed. Can do.

  In the method for producing a multilayer printed wiring board according to the present invention, a laminate is formed by laminating either the resin film or the prepreg on the circuit forming surface of the inner circuit board on which the circuit is formed. A laminating step, an insulating layer forming step of curing the epoxy resin by heating the laminate and forming a resin insulating layer, a roughening treatment step of roughening the surface of the resin insulating layer with a roughening liquid, And a circuit forming step of forming an outer layer circuit by conducting conductor plating on the roughened surface. By such a production method, it is possible to obtain a multilayer printed wiring board having high plating adhesion and having sufficient flame retardancy without containing a halogen flame retardant.

  In another embodiment of the multilayer printed wiring board according to the present invention, the flame-retardant epoxy resin composition varnish is applied to the circuit forming surface of the inner layer circuit board on which the circuit is formed. Thereafter, an insulating layer forming step of forming a resin insulating layer by drying, a roughening step of roughening the surface of the resin insulating layer with a roughening liquid, and conductor plating is applied to the roughened surface. And a circuit forming step for forming an outer layer circuit. By such a production method, it is possible to obtain a multilayer printed wiring board having high plating adhesion and having sufficient flame retardancy without containing a halogen flame retardant.

  By using the flame retardant epoxy resin composition of the present invention, it is possible to provide a multilayer printed wiring board having high plating adhesion and having sufficient flame retardancy without using a halogen flame retardant. it can.

  The flame retardant epoxy resin composition of the present invention includes (A) a bisphenol A type epoxy resin, (B) a modified phenol novolac type epoxy resin having a phosphaphenanthrene structure in the molecule, and (C) a triazine ring in the molecule. A phenolic novolak curing agent having a weight ratio (B) / (A) of the component (B) to the component (A) is 0.5 to 2.

  The bisphenol A type epoxy resin as the component (A) is a bisphenol A type epoxy resin having glycidyl ether of bisphenol A as a basic skeleton. Moreover, it is more preferable to use the bisphenol A type epoxy resin (A-1) which has a phosphorus atom in a molecule | numerator from a viewpoint of improving a flame retardance further.

  Examples of the bisphenol A type epoxy resin (A-1) having a phosphorus atom in the molecule include a bisphenol A type epoxy resin (A-2) having a phosphaphenanthrene structure in the molecule.

  As the bisphenol A type epoxy resin (A-2) having a phosphaphenanthrene structure in the molecule, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide or a derivative thereof is used. Examples thereof include bisphenol A type epoxy resins having various phosphaphenanthrene structures obtained by modifying an A type epoxy resin by a known method. As these products, for example, FX305 manufactured by Toto Kasei Co., Ltd. having a structure as shown in the following formula (1) can be obtained.

  In addition, as an epoxy equivalent of the bisphenol A type epoxy resin which is the said (A) component, it is preferable that it is about 150-600 g / eq.

  The modified phenol novolac epoxy resin having a phosphaphenanthrene structure in the molecule as the component (B) is obtained by using 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide or a derivative thereof. Examples thereof include phenol novolac type epoxy resins having various phosphaphenanthrene structure obtained by modifying a phenol novolac type epoxy resin by a known method. Examples of the phenol novolac type epoxy resin include a cresol novolac epoxy resin in addition to the phenol novolac epoxy resin.

  As these commercially available products, for example, FX289 manufactured by Toto Kasei Co., Ltd., FX289ZA manufactured by Toto Kasei Co., Ltd., etc. having the structure shown in the following formula (2) can be obtained.

（ｎ，ｍ，ｏはそれぞれ整数であり、ｎ，ｍ，ｏのいずれか一つが０の場合も含む）

(N, m, and o are integers, respectively, including the case where any one of n, m, and o is 0)

  The epoxy equivalent of the modified phenol novolac type epoxy resin as the component (B) is preferably about 150 to 400 g / eq.

  In the flame-retardant epoxy resin composition of the present invention, the mass ratio of the component (B) to the component (A) ((B) / (A)) is 0.5 to 2, preferably 0.5. ~ 1. When the mass ratio is less than 0.5 or more than 2, the plating adhesion is lowered.

  In addition, in the flame-retardant epoxy resin composition of this invention, you may contain another epoxy resin in the range which does not impair the effect of this invention.

  Specific examples of the other epoxy resins include, for example, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, alicyclic epoxy resin, polyfunctional phenol diglycidyl ether compound, and polyfunctional alcohol diester. Examples thereof include glycidyl ether compounds, phenol novolac epoxy resins other than the component (B), cresol novolac epoxy resins other than the component (B), bisphenol A type novolac epoxy resins, and the like.

  As a content ratio of the epoxy resin component of the present invention, as a total ratio of the above-described various epoxy resin components (epoxy resin (A), epoxy resin (B) and other epoxy resins), in the total amount of the flame retardant epoxy resin composition 70 to 95% by mass, more preferably 80 to 90% by mass.

  Moreover, as a total content rate of an epoxy resin (A) and an epoxy resin (B), it is preferable to contain 50-100 mass% in an epoxy resin component whole quantity, Furthermore, 70-100 mass% is contained.

  The flame retardant epoxy resin composition of the present invention contains a phenolic novolak curing agent (C) having a triazine ring in the molecule as a curing agent. The phenolic novolak curing agent (C) contains a nitrogen atom in the triazine ring. And it is thought that this nitrogen atom raises plating adhesiveness compared with the normal phenol type novolak hardening | curing agent which does not have a nitrogen atom.

  The phenol novolak curing agent (C) having a triazine ring is obtained by condensing phenols such as phenol and cresol, a compound having a triazine ring and aldehydes.

  Specific examples of the phenolic novolak curing agent (C) having a triazine ring include those represented by the following general formula (3).

（Ｒ_{1 、}Ｒ_２はそれぞれ、メチル基又は水素、ｐは１〜５の整数を表す）。

(R _{1 and} R ₂ are each a methyl group or hydrogen, and p is an integer of 1 to 5).

  The phenolic novolak curing agent (C) having a triazine ring is a commercially available product, for example, “Phenolite series” manufactured by Dainippon Ink & Chemicals, Inc., “Phenolite LA1356 (nitrogen content 19%), "Phenolite LA3018" (nitrogen content 18%), "Phenolite EXB9851" (nitrogen content 8%), etc. can be obtained.

  About the compounding quantity of (C) component, the ratio of the hydroxyl equivalent of (C) component with respect to the epoxy equivalent of the total amount of (A) component and (B) component is 1: 0.3-1: 0. It is preferable that the amount is adjusted to be 7.

  In addition, the flame retardant epoxy resin composition of the present invention preferably contains a curing accelerator in order to accelerate the curing reaction. Any curing accelerator can be used without particular limitation as long as it can accelerate the curing reaction between the epoxy resin component and the curing agent (C). Specific examples include imidazoles such as 2-methylimidazole and cyanoethylimidazole, tertiary amines such as triethylenediamine, and organic phosphines such as triphenylphosphine. These may be used alone or in combination of two or more.

  The flame retardant epoxy resin composition of the present invention may further contain an inorganic filler together with the resin component as described above. Examples of such inorganic fillers include known silicas such as fused silica and crystalline silica, aluminum hydroxide, magnesium hydroxide, E glass powder, alumina, magnesium oxide, titanium dioxide, barium titanate, calcium silicate, calcium carbonate. , Clay, talc and the like. These may be used alone or in combination of two or more. Among these, it is particularly preferable to use silica. In the present invention, when an inorganic filler is contained, it is preferably about 10 to 50% by mass in the total amount of the flame retardant epoxy resin composition.

  Moreover, as an inorganic filler, an average particle diameter is 1 micrometer or less, Furthermore, 0.5 micrometer or less is especially preferable. When the average particle size exceeds 1 μm, the roughness may become too large during the roughening treatment after curing. In addition, the said average particle diameter means the weight average particle diameter measured using the laser diffraction type particle size distribution measuring apparatus.

  The flame retardant epoxy resin composition of the present invention may further contain other additives, for example, a leveling agent, a colorant and the like, as necessary, as long as the effects of the present invention are not impaired.

  The flame-retardant epoxy resin composition of the present invention is prepared by using the above-described components and an organic solvent uniformly mixed with a mixer, a blender, or the like, and prepared into a varnish.

  Examples of the organic solvent include, but are not limited to, aromatic hydrocarbons such as benzene and toluene, amides such as N, N-dimethylformamide (DMF), ketones such as acetone and methyl ethyl ketone, methanol, ethanol, and the like. Alcohols, cellosolves and the like. These may be used alone or in combination of two or more.

  The resin varnish obtained in this way is processed into a prepreg or an adhesive sheet to be used as a material for producing a printed wiring board, or applied to the surface of an inner circuit board on which a circuit pattern is formed. It is used as a paint for forming.

  Below, the resin film and prepreg using the flame-retardant epoxy resin composition of this invention are demonstrated in more detail.

  The resin film of the present invention is performed by a method generally called a casting method. Specifically, for example, the resin varnish is applied to one surface of the support film so as to have a thickness of 5 to 100 μm, and then heated and dried at 80 to 160 ° C. for 1 to 40 minutes to remove the solvent and resin. The components are semi-cured (B-stage) and formed into a film. The thickness of the finally obtained resin film is preferably 5 to 80 μm.

  The support film is not particularly limited as long as it does not dissolve in the resin varnish. For example, polyester film such as PET film, organic resin film such as polyimide film, metal such as copper foil and aluminum foil, etc. A foil or the like is used.

  In addition, when a protective film is applied after applying and drying the resin varnish on the support film, an easy-to-handle resin film is obtained when a vacuum laminator is used to form the resin insulation layer of the multilayer printed wiring board. It is done.

  On the other hand, the prepreg of the present invention is obtained by impregnating the above-mentioned flame retardant epoxy resin composition into a sheet-like substrate and then drying.

  Examples of the sheet-like base material include woven fabric (cloth) or non-woven fabric of inorganic fibers such as glass, aramid cloth, polyester cloth, paper, and the like. Among these, glass cloth is particularly preferably used.

  The prepreg is impregnated by immersing or applying the resin varnish to a sheet-like base material, for example, by heating and drying at 120 to 180 ° C. for about 1 to 40 minutes to remove the solvent and to semi-cure the resin component (B (Stage).

  Next, the manufacturing method of the multilayer printed wiring board using the resin varnish which concerns on this invention, a resin film, and a prepreg is demonstrated.

  First, either the resin film or the prepreg is laminated on the circuit forming surface of the inner circuit board on which a circuit is formed on at least one surface, and further, a resin insulating layer is formed by heating.

  The circuit of the inner layer circuit board is preferably previously black-treated (blackened and oxidized) with an acid solution or the like.

  And when using the said resin film for formation of a resin insulating layer, a resin film is bonded together and laminated | stacked on the circuit formation surface of the said inner-layer circuit board using a vacuum laminator. And after removing the support film of the laminated | stacked resin film, a resin insulating layer is formed on the circuit formation surface of an inner-layer circuit board by heat-hardening with oven etc. FIG.

  The heat curing conditions are preferably heat curing conditions at a temperature of 150 to 170 ° C. for 30 to 120 minutes.

  On the other hand, when the prepreg is used to form a resin insulation layer, after placing the prepreg on the circuit formation surface of the inner circuit board, the resin insulation made of a cured product is heated and pressed by a molding method such as a multistage vacuum press. A layer is formed.

  Examples of the conditions for the heat and pressure molding include conditions of a temperature of 160 to 180 ° C. and a mold pressure of 1.5 to 4.0 MPa for 30 to 120 minutes.

  Further, instead of using a prepreg or a resin film as described above, the resin insulating layer may be formed by applying the above resin varnish to the circuit forming surface of the inner circuit board and then drying. Specifically, a resin varnish is applied to the circuit forming surface to a thickness of about 5 to 100 μm, and then heated at 100 to 200 ° C. for 1 to 90 minutes to form a resin insulating layer.

  Next, the surface of the resin insulation layer formed as described above is roughened with a roughening solution. The roughening treatment increases the plating adhesion.

  The roughening treatment with the roughening solution is performed by immersing the laminate on which the resin insulating layer is formed in the roughening solution. The temperature of the roughening solution is preferably 40 to 90 ° C., and the immersion time is preferably about 1 to 30 minutes.

  The roughening solution is not particularly limited as long as it contains both or one of an acid and an oxidizing agent. For example, it can be roughened with a permanganate such as potassium permanganate, a dichromate, ozone, an oxidizing agent such as hydrogen peroxide / sulfuric acid, nitric acid, or a combination thereof. Moreover, you may carry out in steps, changing the kind of roughening liquid suitably.

  Furthermore, a set of three types of commercially available roughening agents, “Circumposit MLB211” manufactured by Rohm and Haas, “Circusposit MLB213” manufactured by Rohm and Haas, and “Circuposit MLB216” manufactured by Rohm and Haas. It can also be used as a roughening solution.

  When using as a roughening solution a set consisting of three types of "Circumposit MLB211" manufactured by Rohm and Haas, "Circuposit MLB213" manufactured by Rohm and Haas, and "Circuposit MLB216" manufactured by Rohm and Haas First, the laminated board after lamination molding is immersed in “Circuposit MLB211” to swell the resin, and then the laminated board is immersed in “Circuposit MLB213” to dissolve the resin. A roughening treatment with a roughening solution can be carried out by immersing the substrate in a circular deposit MLB216 to neutralize the basic state.

  A multilayer printed wiring board can be obtained by subjecting the roughened surface to conductor plating to form an outer layer circuit. As a method for forming the outer layer circuit, an additive method using a plating process is preferably used.

  As an additive method, a full additive method or a semi-additive method may be used.

  Hereinafter, an example in which the outer layer circuit is formed by the semi-additive method will be described in detail.

  First, a through hole or a non-through hole for forming a through hole or a blind via hole is formed in a laminate having a roughened resin insulating layer by a drill, a laser, or the like. Next, electroless plating such as electroless copper plating is formed on the surface of the resin insulating layer by electroless plating treatment. Then, a plating resist is formed on a portion where the circuit of the electroless plating portion formed on the surface of the resin insulating layer is not formed. Thereafter, an electrolytic plating process is performed to form electrolytic plating such as electrolytic copper plating only on a portion where the plating resist is not formed. Then, the plating resist is removed. Finally, the electroless plating exposed by removing the plating resist is removed by a quick etching method (flash etching), whereby a multilayer printed wiring board on which an outer layer circuit is formed can be obtained. Then, electroless plating and electrolytic plating are formed on the inner surface of the through hole or the non-through hole, thereby forming a through hole or a blind via hole that electrically connects the inner layer circuit and the outer layer circuit. In addition, you may perform an after cure suitably.

  The multilayer printed wiring board thus obtained is a multilayer printed wiring board having high plating adhesion and having sufficient flame retardancy even if it does not contain a halogen-based flame retardant.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited at all by the Example.

First, the raw materials used in this example are summarized below.
<Epoxy resin component>
-Bisphenol A type epoxy resin: 1051 manufactured by Dainippon Ink and Chemicals, Inc. (bisphenol A type solid epoxy resin, epoxy equivalent 480)
Phosphophenanthrene modified bisphenol A type epoxy resin: FX305 manufactured by Toto Kasei Co., Ltd.
Phosphophenanthrene-modified phenol novolac epoxy resin: FX289ZA manufactured by Toto Kasei Co., Ltd.
<Curing agent component>
A cresol novolak compound having a triazine ring in the molecule: LA3018 manufactured by Dainippon Ink & Chemicals, Inc. (in the formula (1), R ₁ and R ₂ are methyl groups, n is 1 to 5, and nitrogen content is 18%)
-Phenol novolac compound: TD2090 manufactured by Dainippon Ink & Chemicals, Inc.
<Curing accelerator>
・ Cyanoethylimidazole: 2E4MZ-CN manufactured by Shikoku Chemicals Co., Ltd.
<Inorganic filler>
・ Spherical silica: SO25R manufactured by Admatechs Co., Ltd.
<Rubber component>
Nitrile butadiene rubber: “PNR-1H” manufactured by JSR Corporation

(Examples 1-5 and Comparative Examples 1-7)
Various compounding ingredients are mixed by the compounding composition shown in Table 1 to form a resin composition, and further, methyl ethyl ketone is added as a solvent and sufficiently stirred, whereby a varnish of an epoxy resin composition having a solid content of 65% by mass is obtained. Prepared.

  Next, the epoxy resin varnish was applied to a release surface of a support film made of polyethylene terephthalate (PET) using a multi coater (“M400” manufactured by Hirano Techseed Co., Ltd.). And it dried at the temperature of 100 degreeC, conveying with the conveyance speed of 20 cm / min, and was set as the semi-hardened (B stage) state. Furthermore, a 20 μm-thick polyethylene (PE) protective film was attached to the coated surface to prepare an epoxy resin film with a protective film.

  A vacuum laminator was used for the lamination molding. Specifically, the surface of the inner layer circuit board (“R-1566” manufactured by Matsushita Electric Works Co., Ltd.) having the inner layer circuit formed on the outer surface in advance is superposed on the resin surface from which the protective film of the epoxy resin film with the protective film is peeled off. After that, lamination molding (temperature 90 ° C., pressure 0.3 MPa) was performed using a vacuum laminator. And the support film was peeled and removed, and the resin insulating layer was formed by making it harden | cure on 160 degreeC * 75 minute conditions in oven.

  Next, the obtained resin insulating layer was roughened by the following procedure using a roughening solution.

  The obtained laminated board on which the resin insulating layer was formed was immersed in a solution of “Circuposit MLB211” manufactured by Rohm and Haas for 6 minutes at 80 ° C. Next, it was immersed for 10 minutes at 80 ° C. in a solution of “Circumposit MLB213” manufactured by Rohm and Haas. Finally, it was immersed in a solution of “Circumposit MLB216” manufactured by Rohm and Haas for 5 minutes at 45 ° C.

  Next, an outer layer circuit was formed on the surface of the roughened resin insulating layer by the following procedure.

  The surface of the roughened resin insulating layer was subjected to electroless copper plating to form electroless copper plating on the surface of the resin insulating layer, and dried at 120 ° C. for 60 minutes. A plating resist was formed on a portion where the circuit on the formed electroless copper plating was not formed. Furthermore, an electrolytic copper plating process was performed.

  Then, after removing the plating resist, the electroless plating was removed by flash etching. The thickness of the plating formed by electroless copper plating and electrolytic copper plating was 20 ± 2 μm, and the plating width was 10 mm.

  After forming the outer layer circuit as described above, a multilayer printed wiring board was obtained by performing aftercuring in an oven at 180 ° C. for 60 minutes. The multilayer printed wiring board obtained as described above was evaluated for flame retardancy, thermal expansion coefficient and plating peel strength by the following methods.

[Flame retardance]
The molded laminate was evaluated according to the UL94 vertical test method.

[Coefficient of thermal expansion (CTE)]
The B-stage resin film obtained above was cured at 180 ° C. for 60 minutes. And the thermal expansion coefficient in the temperature range (50-100 degreeC) below Tg was measured by the tension mode of TMA method (Thermo-mechanical analysis).

[Method of evaluating plating peel strength]
In accordance with the 90 degree peel test method (JIS C6481), the peel strength of the outer layer circuit (copper plating width 10 mm) was measured. For any of the examples and comparative examples, the above measurement was performed with n (number of samples for evaluation) set to 3. In Table 2, “peeling” indicates that the plating did not adhere cleanly and the adhesion was so weak that the peel strength could not be measured.

  From the results shown in Table 1, the multilayer printed wiring boards of Examples 1 to 5 according to the present invention all have a flammability equivalent to V94 or higher and are excellent without using a halogen-based flame retardant. It turns out that it showed flammability. In addition, since all of the thermal expansion coefficients are relatively small at 56 ppm / ° C. or less, it is considered that cracks and the like are hardly generated in the plating even when subjected to a cold test. Further, the plating peel strength was 0.68 kg / cm or more and was high.

  In particular, in Examples 2 to 5 in which bisphenol A type epoxy resin having a phosphaphenanthrene structure in the molecule is used as the bisphenol A type epoxy resin, particularly high flame retardancy equivalent to V-0 is exhibited. As shown, the plating peel strength was particularly high.

  Furthermore, when an inorganic filler is added, the coefficient of thermal expansion is further reduced. Therefore, when subjected to a cold test, cracks and the like are particularly unlikely to occur.

  On the other hand, the multilayer printed wiring board of Comparative Example 3 containing a rubber component as a roughening component did not contain a halogen-based flame retardant, and thus burned completely in the combustion test. Moreover, in the comparative example 2 and the comparative example 3 which do not contain the modified phenol novolak-type epoxy resin which has a phosphaphenanthrene structure in a molecule | numerator as an epoxy resin component, the plating peel strength was low. Furthermore, in the case of the comparative example 5 which used the general phenol novolak type hardening | curing agent as a hardening | curing agent, the peel strength was too low and could not be measured.

  And it contains (A) bisphenol A type epoxy resin, (B) modified phenol novolac type epoxy resin, and (C) phenol novolak curing agent having a triazine ring, but the mass of (B) component relative to (A) component When the ratio (B) / (A) is Comparative Example 6 of 3.0 higher than 2 and 0.33 lower than 0.5, the peel strength is significantly higher than that of the multilayer printed wiring board of the example. It turns out that it is low.

Claims (8)

  (A) a bisphenol A type epoxy resin, (B) a modified phenol novolac type epoxy resin having a phosphaphenanthrene structure in the molecule, and (C) a phenol novolak curing agent having a triazine ring in the molecule, A flame retardant epoxy resin composition, wherein the mass ratio (B) / (A) of the component (B) to the component A) is 0.5-2.   2. The flame retardant epoxy resin composition according to claim 1, wherein the bisphenol A type epoxy resin (A) is a bisphenol A type epoxy resin (A-1) having a phosphorus atom in the molecule.   The bisphenol A type epoxy resin (A-1) having a phosphorus atom in the molecule is a bisphenol A type epoxy resin (A-2) having a phosphaphenanthrene structure in the molecule. Flame retardant epoxy resin composition.   The flame-retardant epoxy resin composition according to any one of claims 1 to 3, further comprising (D) an inorganic filler.   It forms from the flame-retardant epoxy resin composition of any one of Claims 1-4, The resin film characterized by the above-mentioned.   A prepreg formed by impregnating a sheet-like base material with the varnish of the flame-retardant epoxy resin composition according to any one of claims 1 to 4, and drying it.   A laminating step of laminating any one of the resin film of claim 5 or the prepreg of claim 6 on the circuit forming surface of the inner circuit board on which the circuit is formed; An insulating layer forming step of forming a resin insulating layer by curing the epoxy resin by heating, a roughening step of roughening the surface of the resin insulating layer with a roughening liquid, and a conductor on the roughened surface And a circuit forming step of forming an outer layer circuit by plating.   A resin insulation is obtained by applying a varnish of the flame-retardant epoxy resin composition according to any one of claims 1 to 4 on a surface of the inner circuit board on which the circuit is formed, and then drying the varnish. An insulating layer forming step for forming a layer; a roughening step for roughening the surface of the resin insulating layer with a roughening liquid; and circuit formation for forming an outer layer circuit by subjecting the roughened surface to conductor plating. And a process for producing a multilayer printed wiring board.