JPWO2008133246A1 - Epoxy resin composition, resin film, prepreg, and multilayer printed wiring board - Google Patents

Abstract

[PROBLEMS] To maintain flame retardancy without forming a halogen-based flame retardant in an epoxy resin composition when plating is formed on a substrate surface having a low surface roughness composed of a cured product of an epoxy resin composition. Provided are an epoxy resin composition capable of obtaining a substrate that maintains excellent plating adhesion, a resin film and a prepreg obtained from the composition, and a multilayer printed wiring board having a resin insulating layer formed from the composition For the purpose. A biphenyl type epoxy resin (A) having an average epoxy equivalent of less than 450, a bisphenol A type epoxy resin (B) having an average epoxy equivalent of 450 or more, and a phenolic novolac resin having a triazine ring in the molecule. (C), and the mass ratio of the bisphenol A type epoxy resin (B) to the biphenyl type epoxy resin (A) is 0.25 to 2, and an epoxy resin composition is used.

Description

  The present invention relates to an epoxy resin composition, and more particularly to an epoxy resin composition suitably used for forming a resin insulation layer such as a printed wiring board by a build-up method using a plating process. Moreover, it is related with the resin film, prepreg, and multilayer printed wiring board using such an epoxy resin composition.

  Epoxy resin compositions are widely used as printed wiring board materials because of their excellent adhesion, electrical insulation, chemical resistance, and the like.

  As a method for producing a printed wiring board using an epoxy resin material, a roughened substrate surface is obtained by roughening a substrate surface made of a cured epoxy resin composition with a roughening liquid such as an oxidizing agent. A method of forming a circuit by etching a circuit pattern after forming a conductor layer (plating layer) using a plating process is widely used. The said roughening process is a process of roughening the surface in order to improve adhesiveness with the plating layer formed at a plating process. In the conventional roughening treatment, the unevenness of the roughened surface has a relatively high surface roughness such as ten-point average roughness Rz = 10 μm and arithmetic average roughness Ra = 1 μm. The plating adhesion strength is increased.

  However, when a circuit having a fine pitch with a narrow wiring interval, for example, a wiring interval of 10 to 20 μm as required in recent years, is formed on the surface of a substrate having a relatively large surface roughness as described above. Since the surface of the plated layer was too rough, it was difficult to form an accurate circuit pattern. Therefore, when forming a fine pitch circuit as described above, a base having a relatively low roughness, for example, a ten-point average roughness Rz = 3 μm or less and an arithmetic average roughness Ra = 0.3 μm or less. A plating layer formed on the material surface is used.

  By the way, since epoxy resin is relatively poor in flame retardancy, epoxy resin compositions used for printed wiring boards are generally halogenated flame retardants such as brominated flame retardants and tetrabromobisphenol A type. A halogen-based flame retardant having a high effect of imparting flame retardancy such as a halogen-containing epoxy resin such as an epoxy resin is blended. However, a cured product of such an epoxy resin composition containing a halogen may generate harmful substances such as hydrogen halide at the time of combustion, and has a drawback of adversely affecting the human body and the natural environment. .

  In order to eliminate this drawback, for example, a phosphorus compound such as a phenoxyphosphazene compound is blended in place of the halogen-based flame retardant, and further, a novolac type epoxy resin is used as an epoxy resin, and an amino-modified novolak type phenol resin is used as a curing agent. An epoxy resin composition containing no halogen is disclosed (for example, see Patent Document 1).

However, when plating is formed on the surface of a base material with a low degree of roughening using an epoxy resin composition that does not contain a halogen-based flame retardant as described in Patent Document 1, the adhesion of plating is poor. A phenomenon occurred.
Japanese Patent No. 36550090

  The present invention has been made in view of the above points, and in the case where plating is formed on a substrate surface having a low surface roughness made of a cured product of an epoxy resin composition, the halogen-based flame retardant is added to the epoxy resin composition. Even if it does not contain, it aims at providing the epoxy resin composition which can maintain a flame retardance and can obtain the base material which maintains the adhesiveness of the outstanding plating.

  The epoxy resin composition according to one aspect of the present invention includes a biphenyl type epoxy resin (A) having an average epoxy equivalent of less than 450, a bisphenol A type epoxy resin (B) having an average epoxy equivalent of 450 or more, and a molecule. And a phenolic novolak resin (C) having a triazine ring, and a mass ratio (B / A) of the bisphenol A type epoxy resin (B) to the biphenyl type epoxy resin (A) is 0.25 to 2 It is an epoxy resin composition characterized by being.

  Objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description.

  Hereinafter, the present invention will be described with reference to embodiments. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.

(Epoxy resin composition)
The epoxy resin composition according to the present embodiment includes a biphenyl type epoxy resin (A) having an average epoxy equivalent of less than 450, a bisphenol A type epoxy resin (B) having an average epoxy equivalent of 450 or more, and triazine in the molecule. A phenolic novolak resin (C) having a ring, and a mass ratio (B / A) of the bisphenol A type epoxy resin (B) to the biphenyl type epoxy resin (A) is 0.25 to 2. It is characterized by. The total content of the biphenyl type epoxy resin (A) and the bisphenol A type epoxy resin (B) is preferably 40% by mass or more, more preferably 50% by mass or more, based on the total amount of epoxy resin. It is more preferable that

  The biphenyl type epoxy resin (A) has an average epoxy equivalent of less than 450, preferably 400 or less, and more preferably 350 or less. When the epoxy equivalent is 450 or more, the crosslink density of the cured portion formed by this epoxy resin is not much different from the crosslink density of the cured portion formed by bisphenol A type epoxy resin (B), which will be described later. Tends to be a cured product having a relatively low crosslinking density. Therefore, when the roughening treatment is performed, the surface roughness becomes too large, and it may be difficult to obtain a high-density multilayer printed wiring board. Moreover, it is preferable that the average epoxy equivalent of the said biphenyl type epoxy resin (A) is 150 or more. When the average epoxy equivalent is too small, a cured portion having a too high crosslinking density is formed, so that the surface roughness of the surface formed by the roughening treatment becomes too small and the plating adhesion tends to be lowered. There is.

  Specific examples of the biphenyl type epoxy resin (A) include, for example, NC3000H (average epoxy equivalent 290) manufactured by Nippon Kayaku Co., Ltd. having a structure as shown in the following general formula (1), Nippon Kayaku ( NC3000FH (average epoxy equivalent 336) manufactured by Co., Ltd.

（式中、ｎは、１〜１０を示す。）

(In the formula, n represents 1 to 10.)

  Moreover, the said epoxy resin composition is an epoxy resin whose average epoxy equivalent is 300 or less, Comprising: Epoxy resins other than the said biphenyl type epoxy resin (A) may be included. Specific examples of such epoxy resins include, for example, bisphenol type epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, and alicyclic epoxies having an average epoxy equivalent of 300 or less. Resin, diglycidyl ether compound of polyfunctional phenol, diglycidyl ether compound of polyfunctional alcohol, phenolic novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolak which is glycidyl etherified product of polycondensate of phenol and formaldehyde Type epoxy resin and the like. These may be used alone or in combination of two or more. Among these, a phenol-based novolak type epoxy resin (E) having an average epoxy equivalent of 300 or less is preferable in that it can improve the glass transition temperature Tg of the obtained cured product and provide a cured portion having excellent strength. Furthermore, by using a phenolic novolac type epoxy resin (E) having an average epoxy equivalent of 300 or less and a bisphenol A type epoxy resin (F) having an average epoxy equivalent of 300 or less in combination, a cured product that is more easily stretched is obtained. It is more preferable in that it can be formed and the effect of high plating followability can be exhibited. This is because the biphenyl type epoxy resin (A) and the bisphenol A type epoxy resin (B) are further included by further including a bisphenol A type epoxy resin (F) having an average epoxy equivalent that is liquid at room temperature of 300 or less. It is considered that these resin compositions are homogenized when the phenolic novolac epoxy resin (E) is mixed to obtain a cured product such as a film. Generally, it is known that even if the toughness and strength are improved, but there is a part that is fragile, the film breaks from the fragile part and the elongation deteriorates. By further including the bisphenol A type epoxy resin (F) having an equivalent weight of 300 or less, the fragile parts as described above are reduced, and it is considered that an easily stretchable product can be obtained.

  The bisphenol A type epoxy resin (B) has an average epoxy equivalent of 450 or more. When the average epoxy equivalent is less than 450, the crosslink density of the cured portion formed by the epoxy resin is not much different from the crosslink density of the cured portion formed by the epoxy resin (A). The cured product has a relatively high crosslink density. Therefore, the surface roughness becomes too small and the plating adhesion is lowered. Moreover, it is preferable that the average epoxy equivalent of the said bisphenol A type epoxy resin (B) is 500 or less. When the average epoxy equivalent is too large, a cured portion having a too low crosslinking density is formed, so that the surface roughness tends to be too large. Preferable specific examples of the bisphenol A type epoxy resin (B) include, for example, 1051 (bisphenol A type solid epoxy resin, average epoxy equivalent 480) manufactured by Dainippon Ink & Chemicals, Inc.

  Moreover, the said epoxy resin composition is an epoxy resin whose average epoxy equivalent is 450 or more, Comprising: Epoxy resins other than the said bisphenol A type epoxy resin (B) may be included. Specific examples of such an epoxy resin include, for example, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, alicyclic epoxy resin, difunctional phenol diphenol having an average epoxy equivalent of 450 or more. Examples include glycidyl ether compounds, diglycidyl ether compounds of polyfunctional alcohols, phenolic novolac epoxy resins, cresol novolac epoxy resins, bisphenol A novolac epoxy resins that are glycidyl etherified products of polycondensates of phenols and formaldehyde. . These may be used alone or in combination of two or more.

  The biphenyl type epoxy resin (A) and the bisphenol A type epoxy resin (B) include an average epoxy equivalent of the biphenyl type epoxy resin (A) and an average epoxy of the bisphenol A type epoxy resin (B). It is preferable to select a combination of epoxy resins such that the difference from the equivalent is 200 to 400. When the difference in the average epoxy equivalent is too small, the roughening agent for the cured portion having different crosslink densities formed by both the biphenyl type epoxy resin (A) and the bisphenol A type epoxy resin (B) is used. There is a tendency that the difference in solubility becomes insufficient and the expression of the effect of the present invention having high plating adhesion despite the small surface roughness becomes small. Moreover, when the difference of the said average epoxy equivalent is too large, there exists a tendency for it to become difficult to form the roughening surface excellent in the balance of surface roughness and adhesiveness because the difference in crosslinking density is too large.

  Moreover, mass ratio (B / A) of the said bisphenol A type epoxy resin (B) with respect to the said biphenyl type epoxy resin (A) is 0.25-2. When this mass ratio is too low, the ratio of the portion having a high crosslinking density becomes too high, and the surface roughness of the surface formed by the roughening treatment becomes too small. Moreover, when too high, the ratio of the part with low crosslinking density is too high, and the surface roughness of the surface formed by a roughening process becomes large too much. Therefore, when the mass ratio is within the above range, the ratio of the cured portion having a relatively high crosslink density and the cured portion having a relatively low crosslink density formed in the resin insulating layer is suitable, and higher plating adhesion is exhibited. To do.

  Furthermore, from the viewpoint of further improving the flame retardancy, it is preferable to further include a phosphorus-containing epoxy resin (D) having a phosphorus atom in the molecule.

  As the phosphorus-containing epoxy resin (D), for example, an epoxy resin having a phosphaphenanthrene structure in the molecule is preferable, a biphenyl type epoxy resin (D1) having a phosphaphenanthrene structure in the molecule, and a phosphaphenanthrene in the molecule. A bisphenol type epoxy resin (D2) having a structure and a phenol novolac type epoxy resin (D3) having a phosphaphenanthrene structure in the molecule are more preferable.

  As a biphenyl type epoxy resin (D1) having a phosphaphenanthrene structure in the molecule, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- having a structure represented by the following general formula (2): Examples thereof include biphenyl type epoxy resins having various phosphaphenanthrene structures obtained by modifying a biphenyl type epoxy resin by a known method using an oxide or a derivative thereof. Specific examples thereof include, for example, YX4000 manufactured by Japan Epoxy Resin Co., Ltd. having a structure represented by the following general formula (3), 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10. -Epoxy resins obtained by modification with oxides.

As the bisphenol type epoxy resin (D2) having a phosphaphenanthrene structure in the molecule, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide or a derivative thereof is used, and a bisphenol A type epoxy resin is used. And bisphenol type epoxy resins having various phosphaphenanthrene structures obtained by modifying bisphenol type epoxy resins such as bisphenol F 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 (4) can be obtained.

  As the phenolic novolak epoxy resin (D3) having a phosphaphenanthrene structure in the molecule, a phenolic novolak type using 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide or a derivative thereof is used. Examples thereof include phenol-based novolak-type epoxy resins having various phosphaphenanthrene structures obtained by modifying an epoxy resin by a known method. As these products, for example, FX289ZA manufactured by Toto Kasei Co., Ltd. having a structure as shown in the following formula (5) can be obtained.

  Moreover, when it contains the said phosphorus containing epoxy resin (D), it is preferable that the content rate of a phosphorus atom is 0.5-1.5 mass% with respect to the total amount of epoxy resins. If this content is too low, the effect of improving flame retardancy by the phosphorus-containing epoxy resin (D) tends to be reduced, and if this content is too high, the water absorption and heat resistance tend to deteriorate. is there.

  The epoxy resin composition contains a phenolic novolak resin (C) having a triazine ring in the molecule as a curing agent. The phenolic novolak resin (C) having a triazine ring in the molecule is a phenolic novolak resin containing a structural unit derived from a compound having a triazine ring, and contains a nitrogen atom of the triazine ring. When the phenolic novolak resin (C) containing a nitrogen atom of the triazine ring is used as the curing agent, the crosslinking density is compared with the case of using a phenol novolak resin such as a cresol novolak resin containing no nitrogen atom. Since a highly cured portion and a cured portion having a relatively low crosslinking density are uniformly mixed, the density of the unevenness can be further increased and higher plating adhesion can be exhibited.

  Preferable specific examples of the phenol novolak resin (C) include, for example, aminotriazine novolak resin (C1). In the aminotriazine novolak resin (C1), a cured portion having a relatively high crosslinking density and a cured portion having a relatively low crosslinking density are more dispersed and mixed. Therefore, the density of the unevenness is further increased, and higher plating adhesion can be exhibited. Furthermore, the amino group contained in the aminotriazine novolak resin (C1) is likely to form a portion having a low crosslinking density with the epoxy group.

  In addition, since the phenolic novolak resin (C) has a large number of nitrogen atoms in the molecule, a large amount of incombustible gas or inert gas such as nitrogen gas is generated as a decomposition gas during combustion, which is relatively difficult. Exhibits flammability. Further, the biphenyl type epoxy resin (A) also has a relatively high flame retardancy. From these facts, the cured product of the epoxy resin composition according to the present embodiment in which the biphenyl type epoxy resin (A) and the phenolic novolak resin (C) are dispersed does not contain a halogen. Can exhibit flame retardancy. Moreover, it is preferable that the hydroxyl group equivalent (OH equivalent) of a phenol type novolak resin (C) is 100-200.

  The amount of the phenolic novolak resin (C) is the ratio of the hydroxyl equivalent of the phenolic novolak resin (C) to the average epoxy equivalent of all the epoxy resins including the epoxy resin (A) and the epoxy resin (B). It is preferable to adjust so that (OH equivalent / epoxy equivalent) is 0.3 to 0.7. When this ratio is too low or too high, the heat resistance of the cured product tends to decrease.

  Moreover, it is preferable that the nitrogen content rate of the said phenol type novolak resin (C) is 5% or more. When the nitrogen content is too low, the plating adhesion decreases.

  Preferable specific examples of the phenolic novolak resin (C) include, for example, “Phenolite LA1356 (nitrogen content 19%)”, “Phenolite” as “Phenolite series” manufactured by Dainippon Ink and Chemicals, Inc. LA3018 (nitrogen content 18%) "," Phenolite LA7052 (nitrogen content 8%) "and the like.

  The epoxy resin composition may contain 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 and the curing agent. Specific examples include imidazoles such as 2-methylimidazole, tertiary amines such as triethylenediamine, and organic phosphines such as triphenylphosphine. These may be used alone or in combination of two or more.

  The epoxy resin composition may further contain an inorganic filler together with the resin component as described above. Examples of such inorganic fillers include known 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. Of these, silica is preferably used. It is preferable that the content rate of the said inorganic filler shall be 5-80 mass% with respect to the epoxy resin composition whole quantity.

  Moreover, as said inorganic filler, it is preferable that an average particle diameter is 1 micrometer or less. When the average particle size is too large, 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 epoxy resin composition may further contain other additives, for example, a flame retardant, a flame retardant aid, a leveling agent, a colorant and the like, as necessary, within a range not impairing the effects of the present invention.

  Moreover, the said epoxy resin composition may contain the organic solvent as needed. 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 epoxy resin composition is formed by applying an epoxy resin composition adjusted to a resin varnish on the outer surface on which the conductor layer of the inner circuit board is formed, and then drying to form a resin insulation layer, A resin film or prepreg made of an epoxy resin composition is formed, and the resin film or prepreg is placed on the outer surface of the inner circuit board on which the conductor layer is formed, and bonded together by pressing or heating. Can be formed.

  Below, each embodiment which concerns on the resin film, prepreg, and multilayer printed wiring board using the said epoxy resin composition is demonstrated in detail.

(Resin film)
The resin film according to the present embodiment is formed from the epoxy resin composition. Such a resin film can be produced by a casting method or the like using a resin varnish formed from the epoxy resin composition. For example, after applying the resin varnish to one surface of the support film so as to have a thickness of 5 to 100 μm, the resin varnish is dried by heating at 80 to 160 ° C. for 1 to 40 minutes to remove the solvent and semi-cure the resin component ( B-stage) and forming into a film. At this time, the thickness of the resin film is preferably 5 to 80 μm. Also, after applying and drying the resin varnish on the support film, a protective film can be applied to obtain a resin film suitable for application of a vacuum laminator. For example, it can be applied to the resin insulation layer of a multilayer printed wiring board. Provided.

  In the above method, if the surface of the support film is previously treated with a release agent, the molded resin film can be easily peeled off from the support film, thereby improving workability. The support film is not particularly limited as long as it does not dissolve in the resin varnish. For example, in addition to a polyester film such as a polyethylene terephthalate (PET) film, an organic film such as a polyimide film, a copper foil Metal foil such as aluminum foil can be used.

(Prepreg)
The prepreg according to this embodiment is obtained by impregnating a sheet-like base material with the epoxy resin composition. For example, a prepreg can be produced by the following method. More specifically, after impregnating the resinous varnish into the resinous varnish by impregnating the resinous varnish into the resinous varnish, the resin varnish is dried by heating at 120 to 180 ° C. for 1 to 40 minutes, And the resin component is semi-cured (B-stage). At this time, it is preferable that the resin amount in a prepreg is 30-80 mass% with respect to the prepreg whole quantity. The sheet-like substrate is not particularly limited, but preferably a sheet-like fiber substrate is used. For example, a woven fabric (cloth) or a nonwoven fabric of inorganic fibers such as glass, an aramid cloth, Polyester cloth, paper, and the like can be used.

(Multilayer printed wiring board)
The multilayer printed wiring board according to the present embodiment is a multilayer printed wiring board in which a resin insulating layer and a conductor layer are alternately laminated on a conductor layer of an inner circuit board, and the resin insulating layer includes the epoxy resin. It is formed from a composition.

  As a manufacturing technique of a multilayer printed wiring board, a build-up method in which a resin insulating layer and a conductor layer are alternately stacked on a conductor layer of an inner circuit board is known, and the multilayer printed wiring board is the build-up method. In the manufacturing process of the multilayer printed wiring board according to, for example, after forming a cured resin insulating layer using the resin film, the surface of the surface is roughened by a roughening liquid, and the surface is roughened, It is obtained by forming the conductor layer laminated thereon by a plating process.

  Hereinafter, a specific form of the multilayer printed wiring board will be described while explaining a method for manufacturing the multilayer printed wiring board.

  In order to obtain the multilayer printed wiring board, first, an inner layer circuit board having an inner layer circuit formed on the outer surface in advance is prepared, and the inner layer circuit of the circuit board is black-oxidized (blackening process) using an acid solution or the like. An inner layer roughening process such as the above is performed. Next, a resin film is laminated and formed on the outer surface of the inner layer circuit board using a vacuum laminator, and the support film of the laminated resin film is removed, followed by heat curing in an oven or the like. Next, the surface of the cured resin film is roughened with a roughening liquid.

  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 an oxidizing agent such as permanganate, dichromate, ozone, hydrogen peroxide / sulfuric acid, nitric acid. In addition, a set of three types of “Raku & Haas” “Circuposit MLB211”, Rohm & Haas “Circuposit MLB213” and Rohm & Haas “Circuposit MLB216” may be used as a roughening solution. it can. The roughening treatment with the roughening solution can be performed by immersing the laminated plate after the resin film lamination molding in the roughening solution, and can be performed a plurality of times by changing the type of the roughening solution. The temperature of the roughening solution can be set to 40 to 90 ° C., and the immersion time can be set to 1 to 30 minutes.

  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.

  Then, a multilayer printed wiring board can be obtained by forming an outer layer circuit by the well-known additive method on the surface of the resin insulating layer roughened as described above. The additive method includes a full additive method and a semi-additive method, and in this embodiment, any method may be used to form the outer layer circuit. Hereinafter, an example in which the outer layer circuit is formed by the semi-additive method will be described.

  First, in order to form a through hole or a blind via hole, a through hole or a non-through hole is formed in the resin insulating layer by a drill, a laser, or the like, and then a roughening process is performed. Next, an electroless plating treatment is performed to form electroless plating such as electroless copper plating on the surface of the resin insulating layer, and then a plating resist is formed in a portion where the outer layer circuit is not formed. Thereafter, electrolytic plating treatment is performed to form electrolytic plating such as electrolytic copper plating on a portion where the plating resist is not formed, and then the plating resist is peeled off. And the multilayer printed wiring board in which the outer layer circuit was formed can be obtained by removing the electroless plating exposed by peeling of the plating resist by a quick etching method (flash etching). By forming electroless plating and electrolytic plating on the inner surface of the through hole or the non-through hole, a through hole or a blind via hole for electrically connecting the inner layer circuit and the outer layer circuit is formed. In addition, you may perform an after cure suitably.

  Further, the multilayer printed wiring board can be produced using the prepreg instead of the resin film. After impregnating the resin varnish into the sheet-like fiber base material, if the obtained impregnated body is dried by heating with a dryer, a semi-cured B-stage prepreg can be obtained and protected by this prepreg After disposing the films, they are integrally laminated and formed by a forming method such as a multistage vacuum press. Moreover, as lamination molding, a prepreg can also be laminated | stacked with a vacuum laminator. After removing the protective film after molding, a roughening process is performed in the same manner as in the case of using a resin film, and an outer layer circuit is formed by an additive method, whereby a printed wiring board can be obtained. In addition, a glass cloth is preferably used as the sheet-like substrate. For example, “WEA1116” (a glass cloth having a thickness of 0.08 mm) manufactured by Nittobo Co., Ltd. or “WEA1078” (a glass cloth having a thickness of 0.04 mm) is used. Etc. can be used.

  Furthermore, a multilayer printed wiring board can be produced by directly using a resin varnish in place of the resin film and providing a resin insulating layer on the conductor layer of the inner circuit board. That is, it is performed by a method generally called a casting method in the same manner as the production of a resin film, and after applying a resin varnish to the outer surface of the inner layer circuit board preferably in a thickness of 5 to 100 μm, this is performed at 100 to 200 ° C. The heating can be performed for 1 to 90 minutes. In this case, the resin varnish is directly formed into a film on the inner circuit board, but the thickness after drying is preferably 5 to 80 μm. Thereafter, a roughening treatment is performed in the same manner as in the case of using a resin film, and an outer layer circuit is formed by an additive method, whereby a printed wiring board can be obtained.

[Examples 1 to 9 and Comparative Examples 1 to 7]
According to the composition (parts by mass) shown in Tables 1 and 2, an epoxy resin, a phenolic novolak resin having a triazine ring (curing agent), a curing accelerator, and if necessary, an inorganic filler, and further adding methyl ethyl ketone, An epoxy resin varnish having a solid content of 65% by mass was prepared. The following were used as each material. In Comparative Example 5, a flame retardant was added.

(Epoxy resin)
NC3000H: biphenyl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., average epoxy equivalent 290)
NC3000FH: biphenyl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., average epoxy equivalent 336)
N690: Cresol novolac type epoxy resin (Dainippon Ink & Chemicals, average epoxy equivalent 215)
850S: Bisphenol A type liquid epoxy resin (Dainippon Ink Chemical Co., Ltd., average epoxy equivalent 190)
1051: Bisphenol A type solid epoxy resin (Dainippon Ink and Chemicals, average epoxy equivalent 480)
(Curing agent)
ATN: aminotriazine novolak resin (Dainippon Ink & Chemicals, LA3018, nitrogen content 18%, OH equivalent 151)
Cresol novolak resin: KA1165 (OH equivalent 119) manufactured by Dainippon Ink & Chemicals, Inc.
(Curing accelerator)
2E4MZ-CN: Cyanoethylimidazole (manufactured by Shikoku Chemicals Co., Ltd.)
(Inorganic filler)
Silica: Spherical silica (SO25R manufactured by Admatechs Co., Ltd., weight average particle size 0.5 μm)
(Flame retardants)
Phosphorus flame retardant: Phosphazene (Otsuka Chemical Co., Ltd., SPB100)

  Next, the epoxy resin varnish was applied to the release surface of the polyethylene terephthalate support film using a multi-coater ("H400" manufactured by Hirano Techseed Co., Ltd.) and conveyed at a conveyance speed of 50 cm / min. Was dried to a semi-cured (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.

  For lamination molding, a vacuum laminator is used. First, the protective film of the epoxy resin film with the protective film is peeled off on the surface of the inner layer circuit board (“R-1566” manufactured by Matsushita Electric Works Co., Ltd.) on which the inner layer circuit is formed on the outer surface in advance. After superposing the resin surfaces thus obtained, they were laminated (temperature 90 ° C., pressure 0.3 MPa) using a vacuum laminator. And the support film was peeled and removed, it was made to harden | cure on 160 degreeC * 60 minute conditions in oven, and the roughening process of the insulating layer by the roughening liquid was performed.

This roughening treatment was performed in the following order (1) to (3).
(1) The laminated board after lamination molding was immersed in a solution of “Circuposit MLB211” manufactured by Rohm and Haas for 3 minutes at 80 ° C.
(2) Next, it was immersed for 5 minutes at 80 ° C. in a solution of “Circuposit MLB213” manufactured by Rohm and Haas.
(3) Finally, it was immersed for 5 minutes at 45 ° C. in a solution of “Circuposit MLB216” manufactured by Rohm and Haas.

  Thereafter, an outer layer circuit was formed on the surface of the roughened resin insulating layer using the semi-additive method. That is, electroless copper plating treatment was performed to form electroless copper plating on the surface of the resin insulation layer, and then dried at 120 ° C. for 60 minutes to form a plating resist in a portion where no circuit was formed. Furthermore, after performing the electrolytic copper plating treatment, the plating resist was peeled off, and 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 μm or 20 μm.

  After forming the outer layer circuit, aftercuring was performed with a dryer at 180 ° C. for 60 minutes to obtain a multilayer printed wiring board. Using the printed wiring board obtained as described above as an evaluation sample, the plating peel strength, surface roughness, flame retardancy (laminate), film elongation, and glass transition temperature are evaluated by the following methods. went. These results are shown in Tables 1 and 2. In Tables 1 and 2, the average epoxy equivalent of the epoxy resin is abbreviated as “epoxy equivalent”.

<Plating peel strength>
In accordance with a 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) being 3. In Table 2, “peeling” means that the plating did not adhere cleanly and the adhesion was so weak that the peel strength could not be measured.

<Surface roughness (arithmetic average roughness Ra and ten-point average roughness Rz)>
Using the Olympus laser microscope “OLS3000”, the surface of the resin insulation layer after the roughening treatment in each Example and Comparative Example was evaluated under the following conditions.
・ Semiconductor laser: wavelength 408nm
・ Measurement pitch: 0.1 μm
Measurement range: 0.012 mm ² (plane)

<Flame retardance (laminate)>
The flame retardancy was evaluated based on UL94, in which a 0.07 mm (70 μm) thick prepreg was laminated on both sides of a 0.4 mm thick inner circuit board (“R-1566” manufactured by Matsushita Electric Works).

<Film elongation>
The film elongation was measured by a method based on JPCA-BU01 for a cured resin film.

<Glass transition temperature Tg>
The glass transition temperature Tg was measured in a tensile mode of a dynamic viscoelasticity analysis (DMA) method in accordance with JIS-C6481 for a cured resin film.

  From Tables 1 and 2, the following can be seen.

  Biphenyl type epoxy resin (A) having an average epoxy equivalent of less than 450, bisphenol A type epoxy resin (B) having an average epoxy equivalent of 450 or more, and a phenolic novolak compound (C) having a triazine ring in the molecule, A multilayer printed wiring formed using an epoxy resin composition having a mass ratio (B / A) of the bisphenol A type epoxy resin (B) to the biphenyl type epoxy resin (A) of 0.25 to 2 The plates (Examples 1 to 9) all had a high plating peel strength of 0.7 or more, although the surface roughness was small (Rz 3 μm or less, Ra 0.3 μm or less). Moreover, the film elongation was as high as 5% or more. Furthermore, Tg was as high as 140 ° C. or higher, and the flame retardancy was also all high as V-0 evaluation.

  In contrast, multilayer printed wiring boards (Comparative Example 1 and Comparative Example 2) formed using an epoxy resin composition that does not contain a biphenyl type epoxy resin (A) have a low Tg of less than 140 ° C. and are flame retardant. Was also low with a V-1 rating. Furthermore, Comparative Example 2 using only the bisphenol A type epoxy resin (B) having an average epoxy equivalent of 450 or more as the epoxy resin was so low that the peel strength could not be measured, and the plating adhesion was insufficient.

  Multilayer printed wiring boards (Comparative Examples 3 to 5) formed using an epoxy resin composition containing a curing agent other than the phenolic novolak resin (C) having a triazine ring in the molecule had low peel strength. In Comparative Example 5 using a phosphorus-based flame retardant, Tg was low, and peel strength was too low to be measured, and plating adhesion was insufficient.

  In Comparative Example 6 in which the mass ratio of the bisphenol A type epoxy resin (B) to the biphenyl type epoxy resin (A) was less than 0.25, the peel strength was too low to be measured, and the plating adhesion was insufficient. . Further, Comparative Example 7 in which the mass ratio of the bisphenol A type epoxy resin (B) to the biphenyl type epoxy resin (A) was larger than 2 had low peel strength. Furthermore, Tg was low and the flame retardancy was insufficient.

  In addition, when Examples 1 to 3 and 8 having different compositions of epoxy resins having an average epoxy equivalent of 300 or less are compared, the phenolic novolac type epoxy is obtained from Example 1 which is only the biphenyl type epoxy resin (A) (NC3000H). Tg was higher in Example 2 which further contained resin (E) (N690). Further, Example 3 in which three types of NC3000H, N690 and bisphenol A type epoxy resin (F) (850S) having an average epoxy equivalent of 300 or less are used in combination is preferable in that the film elongation becomes high. This indicates that in Example 8 which does not contain N690 and uses two types of NC3000H and 850S in combination, the film elongation does not increase, and thus the above three types of combination improve the film elongation.

  From the above, it was found that Examples 1 to 9 can maintain flame retardancy and maintain excellent plating adhesion without containing a halogen-based flame retardant.

[Examples 10 to 14]
According to the composition (parts by mass) shown in Table 3, an epoxy resin, a phosphorus-containing epoxy resin, a phenolic novolak resin (curing agent) having a triazine ring, a curing accelerator, methyl ethyl ketone, and a solid content of 65 A mass% epoxy resin varnish was prepared. The following were used as each material. In addition, description of what was used in Examples 1-9 and Comparative Examples 1-7 is abbreviate | omitted.

(Phosphorus-containing biphenyl type epoxy resin)
YX4000 (tetramethylbiphenyl type bifunctional epoxy resin manufactured by Japan Epoxy Resin Co., Ltd.) 70 parts by mass, HCA-HQ (9,10-dihydro-9-oxa-10-phosphaphenanthrene manufactured by Sanko Chemical Co., Ltd.) 30 parts by mass of 10-oxide, phenolic hydroxyl group average of 2.0, phosphorus content of about 9.6% by mass, hydroxyl group equivalent of about 162) in 40 parts by mass of methoxypropanol at 110 ° C. By adding 0.2 parts by mass of phenylphosphine and continuing heating and stirring for about 3 hours, the epoxy equivalent in the solid content is about 525, the solid content is 71% by mass, and the phosphorus content in the solid content is about 2.9% by mass. A phosphorus-containing biphenyl type epoxy resin was obtained.

(Phosphorus-containing bisphenol F epoxy resin)
-FX305: manufactured by Toto Kasei Co., Ltd., average epoxy equivalent 500)
(Phosphorus-based novolac epoxy resin containing phosphorus)
-FX289ZA: manufactured by Tohto Kasei Co., Ltd., average epoxy equivalent 336)
Moreover, the manufacturing method of an epoxy resin film and a printed wiring board is the same as that of Example 1 except having changed the composition of the epoxy resin varnish. Using the obtained epoxy resin film and printed wiring board as samples for evaluation, the evaluation of plating peel strength, surface roughness, flame retardancy (single), flame retardancy (laminate), and glass transition temperature was performed. These results are shown in Table 3. In Table 3, the average epoxy equivalent of the epoxy resin is abbreviated as “epoxy equivalent”. Moreover, it is the same as that of the said Examples 1-9 and the evaluation of Comparative Examples 1-5 except the evaluation of a flame retardance (simple substance).

<Flame retardance (single)>
A glass cloth 1037 (thickness 30 μm) is impregnated with an epoxy resin composition and dried in a dryer at 120 to 190 ° C. for about 5 to 10 minutes to produce a semi-cured (B-stage) prepreg. did.

  While 10 sheets of the obtained prepreg were stacked, copper foil was stacked on both outer surfaces. Furthermore, the copper clad laminated board of about 0.5 mm was manufactured by heat-pressing this on the conditions of 140-180 degreeC and 0.98-3.9 MPa. As the copper foil, GT (thickness 0.018 mm) manufactured by Furukawa Circuit Foil Co., Ltd. was used.

  And the copper foil of the surface was removed from the copper clad laminated board by etching, this was cut | disconnected to length 125mm and width 13mm, and the flame retardance was evaluated based on UL94.

  Table 3 shows the following.

  The multilayer printed wiring boards (Examples 10 to 14) formed using the epoxy resin composition containing the phosphorus-containing epoxy resin had a slightly larger surface roughness than the case where the phosphorus-containing epoxy resin was not included. The plating peel strength was as high as 0.7 or higher, and the Tg was as high as 160 ° C. or higher. Furthermore, all the flame retardances of the laminates were evaluated as V-0, and even the flame retardancy of the epoxy resin film alone was as high as V-0 or V-1.

  On the other hand, in the multilayer printed wiring board (for example, Example 2) formed using the epoxy resin composition not containing the phosphorus-containing epoxy resin, the flame retardancy of the laminate was evaluated as V-0. However, the epoxy resin film alone was completely burned.

  From the above, it was found that flame retardance can be further improved by containing a phosphorus-containing epoxy resin.

  As described above in detail, the epoxy resin composition according to one aspect of the present invention includes a biphenyl type epoxy resin (A) having an average epoxy equivalent of less than 450 and a bisphenol A type epoxy resin having an average epoxy equivalent of 450 or more. (B) and a phenolic novolak resin (C) having a triazine ring in the molecule, and the mass ratio (B / A) of the bisphenol A type epoxy resin (B) to the biphenyl type epoxy resin (A) is , 0.25 to 2, an epoxy resin composition.

  When the biphenyl type epoxy resin (A) and the bisphenol A type epoxy resin (B) are cured using the phenol novolac resin (C) as a curing agent, an average epoxy equivalent is less than 450 biphenyl type epoxy. The resin (A) forms a cured portion having a relatively high crosslinking density, and the bisphenol A type epoxy resin (B) having an average epoxy equivalent of 450 or more forms a cured portion having a relatively low crosslinking density. When the surface of the cured product thus formed is roughened, a cured portion having a relatively high crosslinking density is difficult to dissolve, and a cured portion having a relatively low crosslinking density is easily dissolved. Therefore, a cured portion having a relatively low crosslink density is preferentially dissolved to form a recess, and a cured portion having a relatively high crosslink density is gradually and moderately dissolved.

  Further, in this cured product, a cured portion having a relatively high crosslinking density and a cured portion having a relatively low crosslinking density are uniformly mixed, and the bisphenol A type epoxy resin (B) with respect to the biphenyl type epoxy resin (A) is mixed. Since the mass ratio (B / A) is 0.25 to 2, a ratio of a cured portion having a relatively high crosslinking density and a cured portion having a relatively low crosslinking density is suitable. Therefore, even if the surface roughness of the cured product after the roughening treatment is small, a surface with a large number of irregularities per unit surface area (high density of irregularities) is formed and the surface area of the cured product is increased, so that high plating is achieved. Demonstrate adhesion.

  Further, the biphenyl type epoxy resin (A) and the phenolic novolak resin (C) having a triazine ring in the molecule have relatively high flame retardancy, and this highly flame retardant component is uniformly dispersed. Therefore, even if it does not contain a halogen-type flame retardant in an epoxy resin composition, the hardened | cured material which can maintain a flame retardance is obtained.

  As described above, the epoxy resin composition according to one aspect of the present invention is a halogen-based flame retardant for an epoxy resin composition when plating is formed on a substrate surface having a low surface roughness composed of a cured product of the epoxy resin composition. Even if it does not contain, a flame retardance can be maintained and the base material which maintains the adhesiveness of the outstanding plating can be obtained.

  Moreover, it is preferable that the phosphorus containing epoxy resin (D) which has a phosphorus atom in a molecule | numerator is further included. By containing the phosphorus-containing epoxy resin (D), flame retardancy can be further enhanced.

  Moreover, it is preferable that the content rate of a phosphorus atom is 0.5-1.5 mass% with respect to the total amount of epoxy resins. With such a phosphorus atom content, the effect of improving flame retardancy by the phosphorus-containing epoxy resin (D) can be further exhibited.

  Moreover, it is preferable that the said phosphorus containing epoxy resin (D) is a biphenyl type epoxy resin (D1) which has a phosphaphenanthrene structure in a molecule | numerator.

  Moreover, it is preferable that the said phosphorus containing epoxy resin (D) is a bisphenol-type epoxy resin (D2) which has a phosphaphenanthrene structure in a molecule | numerator.

  Moreover, it is preferable that the said phosphorus containing epoxy resin (D) is a phenol type novolak-type epoxy resin (D3) which has a phosphaphenanthrene structure in a molecule | numerator.

  The epoxy resin composition preferably further includes a phenolic novolac type epoxy resin (E) having an average epoxy equivalent of 300 or less. By including a phenol-based novolac type epoxy resin (E) having an average epoxy equivalent of 300 or less, the glass transition temperature Tg can be increased, and the strength is improved.

  In addition to the phenolic novolac type epoxy resin (E), it is more preferable to further include a bisphenol A type epoxy resin (F) having an average epoxy equivalent of 300 or less. By using the phenolic novolac type epoxy resin (E) and the bisphenol A type epoxy resin (F) in combination, the cured product obtained from the epoxy resin composition is more easily extended. Such a cured product that is easily stretched has high followability of plating against vibration and the like. Therefore, it is possible to obtain a base material that is difficult to peel off the plating.

  This is because the biphenyl type epoxy resin (A) and the bisphenol A type epoxy resin (B) are further included by further including a bisphenol A type epoxy resin (F) having an average epoxy equivalent that is liquid at room temperature of 300 or less. It is considered that these resin compositions are homogenized when the phenolic novolac epoxy resin (E) is mixed to obtain a cured product such as a film. Generally, it is known that even if the toughness and strength are improved, but there is a part that is fragile, the film breaks from the fragile part and the elongation deteriorates. By further including the bisphenol A type epoxy resin (F) having an equivalent weight of 300 or less, the fragile parts as described above are reduced, and it is considered that an easily stretchable product can be obtained.

  The biphenyl type epoxy resin (A) preferably has an average epoxy equivalent of 350 or less. Such a biphenyl type epoxy resin (A) has a polyfunctional resin skeleton with a long interval between cross-linking points, so that a cured portion excellent in toughness and strength can be obtained.

  The phenolic novolac resin (C) is preferably an aminotriazine novolac resin (C1). By using the aminotriazine novolac resin (C1) as a curing agent, a cured portion having a relatively high crosslinking density and a cured portion having a relatively low crosslinking density are more dispersed and mixed, so that the unevenness density is further increased. Higher plating adhesion can be exhibited.

  The epoxy resin composition preferably further includes an inorganic filler having an average particle size of 1 μm or less. When such an inorganic filler is contained, plating adhesion can be improved while maintaining the surface roughness small.

  A resin film according to another aspect of the present invention is a resin film formed from the epoxy resin composition. If such a resin film is used, when manufacturing a printed wiring board, the resin insulation layer which is the foundation | substrate of the conductor layer which consists of plating can be formed easily. The formed resin insulation layer can maintain flame retardancy even if it does not contain a halogen-based flame retardant, and has excellent plating adhesion even when plating is formed on a surface with low surface roughness. Can be maintained.

  A prepreg according to another aspect of the present invention is a prepreg formed by impregnating a sheet-like base material with the epoxy resin composition. If such a prepreg is used, the resin insulation layer used as the foundation | substrate of the conductor layer which consists of plating can be easily formed in manufacture of a printed wiring board. The formed resin insulation layer can maintain flame retardancy even if it does not contain a halogen-based flame retardant, and has excellent plating adhesion even when plating is formed on a surface with low surface roughness. Can be maintained.

  A multilayer printed wiring board according to another aspect of the present invention is a multilayer printed wiring board in which a resin insulation layer and a conductor layer are alternately laminated on a conductor layer of an inner circuit board, wherein the resin insulation layer is It is a multilayer printed wiring board characterized by being formed from the said epoxy resin composition. According to such a structure, even if a halogen-based flame retardant is not contained, a resin that can maintain flame retardancy and can maintain excellent plating adhesion even when plating is formed on a surface with low surface roughness. As a result, it is possible to provide a multilayer printed wiring board capable of forming an accurate circuit even when the circuit wiring interval is reduced.

  It is preferable that the resin insulating layer is formed of at least one selected from the resin film and the prepreg. According to such a configuration, the multilayer printed wiring board can be easily provided.

Claims (15)

Biphenyl type epoxy resin (A) having an average epoxy equivalent of less than 450;
Bisphenol A type epoxy resin (B) having an average epoxy equivalent of 450 or more,
A phenolic novolak resin (C) having a triazine ring in the molecule,
An epoxy resin composition, wherein a mass ratio (B / A) of the bisphenol A type epoxy resin (B) to the biphenyl type epoxy resin (A) is 0.25 to 2.   The epoxy resin composition of Claim 1 which further contains the phosphorus containing epoxy resin (D) which has a phosphorus atom in a molecule | numerator.   The epoxy resin composition according to claim 2, wherein the phosphorus atom content is 0.5 to 1.5 mass% with respect to the total amount of epoxy resin.   The epoxy resin composition according to claim 2 or 3, wherein the phosphorus-containing epoxy resin (D) is a biphenyl type epoxy resin (D1) having a phosphaphenanthrene structure in the molecule.   The epoxy resin composition according to claim 2 or 3, wherein the phosphorus-containing epoxy resin (D) is a bisphenol-type epoxy resin (D2) having a phosphaphenanthrene structure in the molecule.   The epoxy resin composition according to claim 2 or 3, wherein the phosphorus-containing epoxy resin (D) is a phenol novolac type epoxy resin (D3) having a phosphaphenanthrene structure in the molecule.   The epoxy resin composition according to any one of claims 1 to 6, further comprising a phenolic novolac type epoxy resin (E) having an average epoxy equivalent of 300 or less.   The epoxy resin composition according to claim 7, further comprising a bisphenol A type epoxy resin (F) having an average epoxy equivalent of 300 or less.   The epoxy resin composition according to any one of claims 1 to 8, wherein an average epoxy equivalent of the biphenyl type epoxy resin (A) is 350 or less.   The epoxy resin composition according to any one of claims 1 to 9, wherein the phenolic novolak resin (C) is an aminotriazine novolac resin (C1).   The epoxy resin composition according to claim 1, further comprising an inorganic filler having an average particle size of 1 μm or less.   It forms from the epoxy resin composition of any one of Claims 1-11, The resin film characterized by the above-mentioned.   A prepreg formed by impregnating a sheet-like base material with the epoxy resin composition according to any one of claims 1 to 11.   It is a multilayer printed wiring board by which a resin insulation layer and a conductor layer are laminated | stacked alternately on the conductor layer of an inner-layer circuit board, Comprising: The said resin insulation layer is an epoxy resin of any one of Claims 1-11. A multilayer printed wiring board characterized by being formed from a composition.   The multilayer printed wiring board according to claim 14, wherein the resin insulating layer is formed of at least one selected from the resin film according to claim 12 and the prepreg according to claim 13.