JP2005298582A - Interlayer insulation sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an interlayer insulation sheet which contains no halogen nor phosphorus, but has sufficient flame retardancy and improved chemical resistance capable of forming circuits under severe chemical conditions such as electroless plating. <P>SOLUTION: The interlayer insulation sheet for obtaining a circuit board is formed from a resin composition comprising (A) a compound having two or more maleimide groups and (B) aluminum hydroxide, and comprising no halogen element. There is provided a circuit board using the interlayer insulation sheet. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention has sufficient flame retardancy without including halogen-containing flame retardants and phosphorus-containing flame retardants used in the field of electronic materials such as electronic / electric parts, printed wiring boards, semiconductor substrates, and IC encapsulants. In addition, the present invention relates to an interlayer insulating sheet having good chemical resistance and a circuit board using the same.

  In the field of electronic materials, flame retardancy is required to ensure fire safety. As for typical laminated board materials for printed wiring boards and semiconductor substrates, Underwriters Laboratories Inc. UL94 standard is required, and it is required to pass the condition of V-1, more preferably V-0, in the vertical combustion test. All the resins used in the field so far contain a halogen-containing compound such as a bromine-containing compound as a flame retardant in order to pass this condition. These halogen-containing compounds have high flame retardancy. For example, aromatic bromine compounds not only generate corrosive bromine and hydrogen bromide by thermal decomposition, but also form highly toxic compounds in the presence of oxygen. There is a possibility (see Non-Patent Document 1).

  For these reasons, materials that do not contain halogen compounds, so-called “halogen-free” materials, have been researched and developed (see, for example, Patent Document 1). Among them, phosphorus-containing compounds such as red phosphorus have been mainly studied as flame retardants replacing halogen-containing compounds. However, phosphorus-containing flame retardants may generate toxic phosphorus compounds such as phosphine during combustion, and when a typical phosphate ester is used as a phosphorus-containing compound flame retardant, the moisture resistance of the composition is significantly impaired. There are drawbacks.

  On the other hand, metal hydroxides are known as other flame retardants. For example, aluminum hydroxide is known to have an effect as a flame retardant by the following reaction that releases crystal water when heated.

2Al (OH) ₃ → Al ₂ O ₃ + 3H ₂ O
However, when a metal hydroxide such as aluminum hydroxide is used alone as a flame retardant, a large amount of addition is necessary to obtain the required flame retardant performance. In the case of a laminate using a general epoxy resin and aluminum hydroxide added as a flame retardant, the amount of aluminum hydroxide required to achieve the UL94 standard V-0 level is Even in the case of using a resin having a skeleton that hardly burns, such as about 70 wt% to 75 wt%, it is necessary to add about 50 wt% of aluminum hydroxide (see Non-Patent Document 2). When the amount of aluminum hydroxide added is large, circuit processing such as etching and plating processing that significantly lowers the chemical composition resistance to acid and alkali, especially the performance of the circuit board having an insulating layer formed of the resin composition and the resin, Since it is carried out under severe acidic and alkaline conditions, the reliability of the circuit board having an insulating layer with poor chemical resistance is not sufficient, and improvement is required.

On the other hand, in the field of electronic components that are required to be light, thin, and small, higher density, thinner thickness, and finer wiring are required. Therefore, a build-up type printed wiring board in which an insulating layer and a conductive layer are repeatedly laminated is provided for these requirements. Above all, the additive type circuit formation using plating called semi-additive and full additive is utilized because the thickness of the conductive layer is reduced and the fine wiring processing is easy. In particular, the formation of an insulating layer using an interlayer insulating sheet and the formation of a conductive layer using plating, unlike the prepreg build-up method, does not include a substrate such as a glass cloth, so it has excellent migration resistance in the XY direction. Therefore, many studies have been made (Patent Documents 2 and 3). By the way, from the viewpoint of flame retardancy, halogen-containing compounds such as brominated epoxy are used in such an interlayer insulating sheet. However, as described above, there are concerns about environmental pollution and the like for halogen-containing compounds, and examples in which these points are taken into consideration include those in which phosphorus-containing compounds are used as described in Patent Document 3. It is. However, since a considerable phosphorus content is required to achieve the flame retardance that is actually required, the hygroscopicity of the sheet when used as an interlayer insulating sheet may be a problem. In addition, since resins with relatively low flame retardancy are used in the resins used in these interlayer insulation sheets, many additions are required when aluminum hydroxide is used instead of halogen flame retardants. As a result, the chemical resistance is reduced, and the components in the insulating layer generated by erosion of the plating solution during circuit formation by the additive method contaminate the plating solution, or between the plated conductor layer and the insulating layer. The adhesive strength between them was weak, or the heat resistance of the formed circuit board was insufficient.
Hitoshi Nishizawa, “Halogen Flame Retardant”, Flame Retardant Polymer, Taiseisha, pp. 69-79 (1992) JP 2003-231762 A Yukihiro Kiuchi, Masatoshi Doichi, Journal of Japan Institute of Electronics Packaging 5 (2) pp. 159-165 (2003) JP 2003-283143 A JP 2002-069270 A

  It is an object of the present invention to obtain an interlayer insulating sheet having improved chemical resistance capable of forming a circuit under severe chemical conditions such as electroless plating, which is halogen-free and phosphorus-free and has sufficient flame retardancy. That is.

  As a result of intensive studies to solve the above problems, the present invention has sufficient flame retardancy when a compound containing a maleimide group and aluminum hydroxide are contained as a resin composition for forming an interlayer insulating sheet. The inventors have found that an interlayer insulating sheet excellent in chemical resistance can be obtained, and completed the present invention.

That is, the present invention relates to the following.
1) An interlayer insulating sheet for making a circuit board, wherein the resin composition forming the sheet is (A) a compound containing at least two maleimide groups, and (B) aluminum hydroxide. An interlayer insulation sheet characterized by not containing a halogen element.
2) The interlayer insulation sheet according to claim 1, wherein the resin composition forming the sheet further does not contain a phosphorus element.
3) The interlayer insulation sheet according to 1) or 2), wherein the weight change is 3% or less when the interlayer insulation sheet is immersed in an alkaline aqueous solution at 50 ° C. or more and 90 ° C. or less for 2 hours or more.
4) The interlayer insulating sheet of 1) to 3), wherein the resin composition forming the sheet contains 2.0% or more of the maleimide compound (A) in terms of nitrogen with respect to the total mass of the resin components.
5) The interlayer insulating sheet according to any one of 1) to 4), wherein the resin composition is applied on a release film and dried.
6) A circuit board manufactured using the interlayer insulating sheet according to any one of 1) to 5).

  The interlayer insulation sheet of the present invention can meet the demand for flame retardancy while being halogen-free and phosphorus-free, and has high chemical resistance. Therefore, the plating solution is not contaminated during circuit formation by electroless plating that requires severe conditions of high temperature and high alkalinity, and the heat resistance of the circuit board to be formed is sufficient.

Hereinafter, the present invention will be described in detail.
The interlayer insulating sheet of the present invention is not particularly limited as long as the resin composition is formed into a sheet shape, but the resin composition is preferably applied and dried on a release film. Used.

  The interlayer insulating sheet of the present invention is characterized by not containing a halogen element. In the present invention, the absence of a halogen element means that the content of the halogen element in the sheet is 0.09% by weight or less in accordance with the definition of halogen-free by the Japan Printed Circuit Industry Association. Moreover, it is preferable that the interlayer insulation sheet of this invention does not contain a phosphorus element further. Containing no phosphorus element also means that the content of phosphorus element in the resin sheet is 0.09% by weight or less in accordance with the above-mentioned definition of halogen-free.

The resin composition forming the interlayer insulating sheet of the present invention is
(A) a compound containing at least two maleimide groups,
(B) It contains aluminum hydroxide as an essential component.
First, each component which comprises the resin composition which forms the sheet | seat of this invention is demonstrated.

(A) Compound containing at least two maleimide groups The compound containing at least two maleimide groups used in the present invention is not particularly limited as long as it is a compound having at least two maleimide groups, preferably It is a compound represented by the following general formula (1).

In the formula, R1 represents an m-valent organic group. m is an integer greater than or equal to 2, Preferably it is 2-10. Preferred examples of the organic group represented by R1 include those selected from the group consisting of the following general formulas (2-1) to (2-3).

(In the formula, Xs may be the same or different from each other, and —CH ₂ —, —C (CH ₃ ) ₂ —, —C (C ₂ H ₅ ) ₂ —, —CO—, —O—, — ( Single bond), —S— or —SO ₂ —, Y may be the same or different from each other, and represents —CH ₃ , —CH ₂ CH ₃ , or a hydrogen atom.
Specific examples of the compound containing at least two or more maleimide groups that can be used in the present invention include, for example, N, N ′-(1,3-phenylene) bismaleimide, N, N ′-[1,3- (2-Methylphenylene)] bismaleimide, N, N ′-(1,4-phenylene) bismaleimide, bis (4-maleimidophenyl) methane, bis (3-methyl-4-maleimidophenyl) methane, bis (4 -Maleimidophenyl) ether, bis (4-maleimidophenyl) sulfone, bis (4-maleimidophenyl) sulfide, bis (4-maleimidophenyl) ketone, 1,4-bis (maleimidomethyl) benzene, 1,3-bis ( 3-maleimidophenoxy) benzene, bis [4- (4-maleimidophenoxy) phenyl] methane, 1,1-bis [4- (3 Maleimidophenoxy) phenyl] ethane, 1,1-bis [4- (4-maleimidophenoxy) phenyl] ethane, 1,2-bis [4- (3-maleimidophenoxy) phenyl] ethane, 1,2-bis [4 -(4-maleimidophenoxy) phenyl] ethane and the like.

  Moreover, as a compound containing the at least 2 or more maleimide group used by this invention, following General formula (3)

(Wherein n is an average value of 0 to 10), a compound containing a maleimide group, and the following general formula (4)

(Wherein, p is an average value of 0 to 10), and a compound containing a maleimide group. These maleimide group-containing compounds (A) can be used alone or in combination of two or more.

  The content of the compound (A) containing at least two or more maleimide groups is a nitrogen atom in the compound (A) containing maleimide groups with respect to the total mass of the resin components excluding the inorganic components in the resin composition. The content is preferably 2.0% by mass or more and 10% by mass or less, and more preferably 3.0% by mass or more and 7.5% by mass or less.

  When the content of the compound (A) containing at least two maleimide groups in the resin composition is within the above range, the obtained interlayer insulating sheet has sufficient flame retardancy. Since the nitrogen atom content in the compound (A) containing a maleimide group is about 14% at the maximum, the total amount of other resin components is about 80% by mass at the maximum.

(B) Aluminum hydroxide The aluminum hydroxide used in the present invention is not particularly limited as long as it is generally used aluminum hydroxide or hydrated alumina. The chemical formula of these aluminum hydroxides is represented by Al (OH) ₃ or Al ₂ O ₃ .3H ₂ O. Aluminum hydroxide releases crystal water when heated and functions not only as a flame retardant, but also as a soluble component for roughening as described later because it is relatively highly soluble in acid and oxidizer solutions. .

As aluminum hydroxide, the content of Na ₂ O contained as impurities is preferably low. The content of Na ₂ O is preferably less than 0.3%, more preferably 0.2% or less, and particularly preferably 0.1% or less. METHOD If Na ₂ O content contained as an impurity in the aluminum hydroxide is large for cleaning, by a method such as is described, for example, in JP-A-8-325011 discloses a Na ₂ O content contained 0. It is preferable to use after reducing to less than 3%.

When the Na ₂ O content in aluminum hydroxide is within the above range, the resin composition containing aluminum hydroxide has high heat resistance. The reason why the heat resistance is high is that the cured state of the resin composition does not become abnormal because Na released from Na ₂ O in aluminum hydroxide inhibits or rapidly accelerates the curing reaction of the resin composition. This is probably because of this. Furthermore, aluminum hydroxide having a low Na ₂ O content is considered to be one of the reasons that the lowest temperature for releasing crystal water is relatively high, which is high in heat resistance. Moreover, when the Na ₂ O content in aluminum hydroxide is within the above range, it is preferable that reliability deterioration due to ion migration hardly occurs when used as a circuit board. The particle size of the aluminum hydroxide used in the present invention is not particularly limited, but those having an average particle size of 0.1 to 10 μm are usually used. These aluminum hydroxides can be used alone or in combination of two or more.

  Moreover, it is preferable to use a coupling agent for said aluminum hydroxide. As the coupling agent, coupling agents such as silane, titanate, aluminate and zircoaluminate can be used. Among these, a silane coupling agent is preferable, and a silane coupling agent having a reactive functional group is more preferable.

  Examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane N-phenyl-γ-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-anilinopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, Examples include 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and the like, and one or more of these are used. . These silane coupling agents are preferably fixed to the aluminum hydroxide surface by adsorption or reaction in advance. When a coupling agent is used, the adhesiveness between aluminum hydroxide and the resin is improved, and the mechanical strength and heat resistance of the resulting circuit board can be expected to be improved.

  Aluminum hydroxide contains 5 to 100 parts by mass, preferably 5 to 80 parts by mass with respect to 100 parts by mass of the total mass of the resin components. When the content of aluminum hydroxide is within the above range, the flame retardancy effect is obtained, the viscosity when it is made into a varnish is appropriate, and the workability is excellent. Moreover, when content of aluminum hydroxide exceeds 100 mass parts (when exceeding 50 wt% of a resin composition), there exists a possibility of having a bad influence on chemical resistance.

  When the interlayer insulating sheet of the present invention is immersed in an alkaline aqueous solution at 50 ° C. or higher and 90 ° C. or lower for 2 hours or more, the weight change is preferably 3% or less. More preferably, it is 0 to 2%. Specifically, the insulating sheet is cut into 5 cm square and weighed, and then the sheet piece is placed in a 4 mol / liter sodium hydroxide solution at 70 ° C. for 2 hours or more, preferably 2 hours. Then, it is allowed to stand for about 10 hours, and then the taken out sheet is dried and the weight is measured again. It is preferable that it is in this range because chemical resistance is good.

In addition to the components (A) and (B) in the resin composition forming the sheet, the interlayer insulating sheet of the present invention includes:
(C) Other resin components,
(D) soluble component for roughening,
Can be included. Hereinafter, the components (C) and (D) will be described.

(C) Other resin component Although it does not receive a restriction | limiting in particular as another resin component in the resin composition which forms the interlayer insulation sheet of this invention, 1 type (s) or 2 or more types are known as a thermosetting resin. It is preferable to use in combination. Specific examples include epoxy resins, phenol resins, cyanate resins, polyimide resins, acrylic resins, polyphenylene ether resins having reactive functional groups, and the like. When an epoxy resin, a phenol resin, or a cyanate resin is used, it is preferable because of good compatibility with the compound (A) when thermosetting.

  The epoxy resin is not particularly limited, but if an epoxy resin containing a large amount of aromatic rings is used, the flame retardancy of the resin composition is improved, and the amount of aluminum hydroxide added as a flame retardant is reduced. The chemical resistance is improved, which is preferable. Epoxy resins containing many aromatic rings include bisphenol A type epoxy, bisphenol F type epoxy, naphthalene type epoxy, cresol novolac type epoxy, bisphenol A novolak type epoxy, phenol aralkyl type epoxy, naphthol aralkyl type epoxy, naphthol novolak type epoxy. Etc. Preferably, cresol novolac type epoxy, naphthol aralkyl type epoxy, or the like is used.

  The phenol resin is not particularly limited, but if a phenol resin containing a large amount of aromatic rings is used, the flame retardancy of the resin composition is improved, and the amount of aluminum hydroxide added as a flame retardant is reduced. The chemical resistance is improved, which is preferable. Examples of the phenol resin containing a large amount of aromatic ring include phenol novolak resin, phenol aralkyl resin, naphthol novolak resin, naphthol aralkyl resin, and bisphenol A novolak resin. Preferably, a phenol aralkyl resin, a naphthol aralkyl resin, or the like is used.

  Examples of the cyanate resin include polyfunctional cyanate esters, prepolymers thereof, or mixtures of polyfunctional cyanate esters and prepolymers, and are not particularly limited. Specific examples of the polyfunctional cyanate ester include 4,4-dicyanatobiphenyl, bis (4-dicyanatophenyl) methane, 2,2-bis (4-cyanatophenyl) propane, and bis (4-cyanato). Phenyl) ether and the like.

  These resin components can be used in combination of two or more components. Preferred combinations include an epoxy resin and a phenol resin, and an epoxy resin and a cyanate resin. These combinations are particularly compatible with the compound (A) when cured.

  The content of the component (C) is preferably about 10 to 90% by weight, more preferably about 20 to 80% by weight in the resin composition.

  Further, a thermoplastic resin component can be added to these resin components as long as the compatibility with the compound (A) does not deteriorate upon thermosetting. These thermoplastic resin components can impart flexibility or improve electrical characteristics when the resin composition is formed into a sheet. Some of these thermoplastic resin components function as a soluble component for roughening as in the component (D) described later. Specific examples of the thermoplastic component include polyphenylene ether resin, polyimide resin, polybutadiene rubber, acrylonitrile-butadiene rubber, and ethylene acrylic rubber, but are not particularly limited. These thermoplastic resins may be partially modified with an epoxy group, a maleic acid group, an imide group, a carboxyl group, a (meth) acryl group, or the like. The range of the molecular weight of these thermoplastic resins is preferably about 1,000 to 1,000,000. Especially preferably, it is about 1000-10000. When the range of molecular weight is in the above range, the compatibility with the compound (A) is good at the time of thermosetting, which is preferable.

(D) Soluble component for roughening In the resin composition forming the interlayer insulating sheet of the present invention, a component for roughening the resin surface is added in order to improve the adhesion strength of plating when plating is performed. can do. That is, the roughening component is a soluble component having a higher dissolution rate in an acid or oxidizer solution than other resin components. Examples of these soluble components for roughening include organic fillers. The shape of the filler includes a spherical shape, a crushed shape, a needle shape, a granular shape, and the like, and is not particularly limited, and these can be used in combination of two or more types. The particle size of the filler is preferably about 0.1 μm to 10 μm, more preferably about 0.1 μm to 5 μm. When the particle size range of the filler is the above, not only is it easy to uniformly disperse in the resin, but also precipitation and aggregation are less likely to occur when it becomes a varnish used when applying and impregnating the resin composition, Excellent workability. These fillers may be subjected to a surface treatment by a known technique in order to improve dispersibility and adhesion with a resin.

If it is resin with said shape as an organic filler, there will be no restriction | limiting in particular. As the resin, rubber resins such as polybutadiene rubber, acrylonitrile-butadiene rubber and carboxylated ethylene acrylic rubber, thermosetting resins such as epoxy resin and phenol resin, thermoplastic resins such as polyolefin resin and silicon resin can be used. Moreover, it may be a multilayer structure (core-shell structure) of two or more kinds of resins.
The addition amount of these organic fillers is preferably in the range of 1 to 20% by mass, more preferably 1 to 10% by mass with respect to the total mass of the resin components excluding the inorganic components in the resin composition. When the addition amount of aluminum hydroxide (B) is relatively large, a sufficient roughening effect can be obtained even if the addition amount of the organic filler is very small.

Curing accelerator It is preferable that the resin composition forming the interlayer insulating sheet of the present invention further contains a curing accelerator. Examples of the curing accelerator include imidazoles such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole tetraphenylborate; Amines such as ethylenediamine and N-methylmorpholine; metal catalyst compounds such as zinc octylate; tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triethylammonium tetraphenylborate; 1,8-diaza-bicyclo (5,4 , 0) Undecene-7 and its derivatives. These curing accelerators can be used singly or in combination of two or more. Preferably, imidazoles, metal catalyst compounds, and the like are used, although depending on the other resin component (C) to be added.

  The content of these curing accelerators is preferably blended so that the desired gelation time of the varnish described later can be obtained, but generally the mass of the resin component excluding the inorganic component in the resin composition. It is preferably used in the range of 0.005 to 10% by mass with respect to the total.

Additives Additives can also be added to the resin composition of the present invention depending on the application. Preferable examples of the additive include dyes, pigments, lubricants, anti-settling agents, antifoaming agents, leveling agents, additives commonly used as surface tension adjusting agents, and the like. Specific examples include fluorine-based, silicone-based, acrylic-based antifoaming agents, and leveling agents. In general, the content of the additive is preferably used in the range of 0.0005 to 10 parts by mass with respect to 100 parts by mass of the total amount of the resin components.

Method for Preparing Resin Composition The resin composition of the present invention comprises, for example, a compound (A) containing at least two maleimide groups, another resin component (C), and a roughening soluble component (D) 80 to 80 A uniform mixture can be obtained by heating and mixing at about 200 ° C. for about 0.1 to 10 hours. When adding aluminum hydroxide (B), said mixture can be grind | pulverized at normal temperature, it can also mix in a powder state, and aluminum hydroxide can also be mixed in the resin varnish described below.

Resin Varnish For the interlayer insulating sheet of the present invention, a resin varnish obtained by dissolving the above resin composition in a solvent can be used in the production.

  Solvents used in the resin varnish include ethylene glycol monoethyl ether, propylene glycol monomethyl ether, ethylene glycol monobutyl ether, N, N-dimethylformamide, N, N-dimethylacetamide, dioxane, acetone, N-methyl-2-pyrrolidone , Dimethyl sulfoxide, methyl ethyl ketone, methyl isobutyl ketone, cyclohexane, 2-heptanone and the like. As the solvent, those having a relatively low boiling point are preferable, and methyl ethyl ketone, acetone, dioxane or a mixture containing these as a main component is preferably used.

  The resin varnish used in the production of the interlayer insulating sheet of the present invention contains other resin components other than the above (A), (B), (C), and (D) within the range not impairing the object of the present invention. You may do it. The content of the compound (A) containing a maleimide group in the resin varnish, aluminum hydroxide (B), other resin component (C), and soluble component for roughening (D) is the same as that of the resin composition.

  The resin varnish preferably contains the curing accelerator as described above, and the content is the same as above. Moreover, the resin varnish can contain the additive etc. which the said resin composition may contain. In the resin varnish, it is desirable that the resin components are contained in a range of usually 50 to 80% by mass, preferably 55 to 75% by mass in total.

  The resin varnish is prepared, for example, by heating and mixing the compound (A) containing a maleimide group and another resin component (C) in an organic solvent to obtain a uniform solution, and then aluminum hydroxide (B), The soluble component for roughening can be mixed and adjusted. Although the temperature at the time of heating and mixing depends on the boiling point of the organic solvent, it is usually 50 to 200 ° C., and the heating and mixing time is usually 0.1 to 20 hours. When mixing (B) and (D), a roll kneader such as a two-roll or a three-roll may be used at room temperature or under heating, and equipment such as a rough machine, a ball mill, a shaker, etc. It can carry out by the well-known method used.

Release film The interlayer insulation sheet of this invention can be manufactured by apply | coating the said resin composition on a release film, and then drying and removing a solvent. As the release film, all known films conventionally used as release films can be used. Specifically, a polyethylene terephthalate (PET) film, a polypropylene film, a 4-methylpentene-1 film, a fluororesin film, and the like. After the resin varnish is applied to the release film, a film is produced through a drying process. However, the application method and the drying method are not particularly limited and conventionally known methods are used.

  The drying conditions are appropriately determined depending on the boiling point of the solvent to be used, but it is desirable that the amount of the residual solvent in the sheet is 1% by mass or less. As a specific example, a residence time of about 5 minutes to 10 minutes is preferable in the range of 140 ° C. to 220 ° C., but in the manufacturing process in which the sheet is continuously dried, the optimum temperature range is transported. This is not the case because it changes depending on the speed.

Interlayer Insulating Sheet The interlayer insulating sheet of the present invention can be used alone as an interlayer insulating sheet, or can be used by being laminated with other interlayer insulating sheets or sheet type interlayer insulating materials such as prepregs. In the case of laminating with another interlayer insulating material such as a prepreg, the interlayer insulating sheet of the present invention can be laminated on one side or both sides of the interlayer insulating material using a known method. Specifically, a laminator or the like is used to perform lamination and pressure bonding under heating and pressure.

Circuit Board Next, a method for manufacturing a circuit board manufactured using the interlayer insulating sheet of the present invention will be described. In the circuit board of the present invention, first, the interlayer insulating sheet is laminated on an inner layer substrate that has been patterned and formed into a circuit, and is heated and cured by heat pressing under heating and pressing conditions to form an insulating layer. The inner layer substrate is not particularly limited, and a known substrate such as a glass epoxy substrate, a polyimide substrate, a bismaleimide triazine substrate, or a thermosetting polyphenylene ether substrate can be used. Further, the surface of the conductor portion of the circuit board may be previously roughened. The conditions for heat curing are preferably in the range of 30 minutes to 2 hours under conditions of 150 ° C. or more and less than 250 ° C. Next, in order to form a through hole and a via hole at an arbitrary position, drilling and / or laser drilling is performed. After that, roughening treatment is performed using permanganate, dichromate, a mixture of hydrogen peroxide and sulfuric acid, and an acid / oxidizer solution such as nitric acid. Next, a plating resist layer is formed. As the plating resist layer, a permanent resist such as photosensitive polyimide may be used, or a peelable resist layer may be used. Then, by forming a conductor layer by performing electroless plating and / or electrolytic plating, an additive or semi-additive circuit can be formed. By carrying out heat treatment at 150 ° C. to 250 ° C. for 15 minutes to 90 minutes after forming the conductor layer, curing of the resin composition can be promoted, and heat resistance and peel strength can be improved.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.

Examples 1-4 and Comparative Examples 1-3
Among the compositions shown in Table 1, the resin component was dissolved in a mixed solvent of methyl ethyl ketone: N-methyl-2-pyrrolidone (mixing ratio is methyl ethyl ketone: N-methyl-2-pyrrolidone = 4: 1) at 80 ° C. for 6 hours. A resin varnish was obtained. To the resin varnish thus obtained, aluminum hydroxide, a curing accelerator, a roughening soluble component and an additive were added and stirred uniformly, applied to a PET film (thickness of about 25 μm), and dried at 150 ° C. for 5 minutes. Thus, an interlayer insulating sheet having a film thickness of about 30 μm was obtained. When the content of halogen ions and phosphate ions of these interlayer insulating sheets was measured by ion chromatography in accordance with the standard JPCA-ES-01 of the Japan Printed Circuit Industry Association, both were 0.09 wt% or less.
(Flame retardancy test)
These insulating sheets were cut out to 50 mm × 200 mm, the afterflame time after flame contact by the UL94VTM method was measured, and VTM-0, VTM-1, and VTM-2 were determined.
(Chemical resistance test)
These insulating sheets were cut into 5 cm squares, and the PET film was peeled off and then weighed. Further, these sheet pieces were left in a 4 mol / liter sodium hydroxide solution (70 ° C.) with stirring for 2 hours. After drying at 150 ° C. for 30 minutes, the weight was measured again, and the weight loss was divided by the initial weight to obtain a weight reduction rate to make it chemical resistant.

In the examples and comparative examples, the following raw materials were used.
(A) a compound containing a maleimide group;
BMI-S (trade name, nitrogen atom content: about 8%, manufactured by Mitsui Chemicals, Inc.)
BMI-MP (trade name, nitrogen atom content: about 10%, manufactured by Mitsui Chemicals, Inc.)
(B) aluminum hydroxide;
Aluminum hydroxide; HS-330 (trade name, average particle diameter: 7 μm, Na ₂ O amount: 0.04%, manufactured by Showa Denko KK)
CL-303 (trade name, center particle size: 2.5 μm, Na ₂ O amount: 0.21%, manufactured by Sumitomo Chemical Co., Ltd.)
(C) Other resin components;
Naphthalene type epoxy resin, Epicron HP4032 (trade name, epoxy equivalent 150, manufactured by Dainippon Ink & Chemicals, Inc.)
Naphthol aralkyl resin, SN485 (trade name, OH equivalent 215, manufactured by Nippon Steel Chemical Co., Ltd.)
Cyanate resin, AROCY B10 (trade name, manufactured by Asahi Ciba Epoxy Co., Ltd.)
(D) soluble component for roughening;
Epoxidized polybutadiene, E-1000 (trade name, manufactured by Nippon Petrochemical Co., Ltd.)
Epoxidized polybutadiene, Epolide PB-3600 (trade name, manufactured by Daicel Chemical Industries, Ltd.)
Curing accelerator;
2-Ethyl-4-methylimidazole (2E4MZ (trade name), manufactured by Shikoku Kasei Kogyo Co., Ltd.)
Zinc octylate

Compared with the Examples, Comparative Example 1 did not contain a maleimide compound, had insufficient flame retardancy, and also had insufficient chemical resistance. Moreover, since the comparative example 2 did not contain aluminum hydroxide, the flame retardance was insufficient.

  Since flame retardancy can be obtained without containing halogen compounds and phosphorus compounds, circuit board materials used for electronic components, etc. have relatively low environmental impact (does not contain compounds that can adversely affect the environment) ) Can be used. Moreover, since it is excellent in chemical resistance, a circuit board using electroless plating can be produced, and finer wiring and easier impedance control can be achieved.

Claims (6)

An interlayer insulating sheet for making a circuit board, wherein the resin composition forming the sheet is (A) a compound containing at least two maleimide groups, (B) aluminum hydroxide, and halogen An interlayer insulating sheet characterized by not containing an element. The interlayer insulation sheet according to claim 1, wherein the resin composition forming the sheet further does not contain a phosphorus element. 3. The interlayer insulation sheet according to claim 1, wherein when the interlayer insulation sheet is immersed in an alkaline aqueous solution at 50 ° C. or more and 90 ° C. or less for 2 hours or more, the weight change is 3% or less. The interlayer insulation sheet according to claims 1 to 3, wherein the resin composition forming the sheet contains 2.0% or more of the maleimide compound (A) in terms of nitrogen with respect to the total mass of the resin components. It is an interlayer insulation sheet of any one of Claims 1-4, Comprising: The interlayer insulation sheet formed by apply | coating and drying a resin composition on a release film. The circuit board manufactured using the interlayer insulation sheet of any one of Claims 1-5.