JP5098432B2 - Metal foil with adhesive layer, metal-clad laminate and printed wiring board using the same - Google Patents

Description

  The present invention relates to a metal foil with an adhesive layer, a metal-clad laminate using the same, and a printed wiring board.

  A printed wiring board is obtained by heat-press molding a structure in which a prepreg formed by impregnating and drying a varnish of a thermosetting resin composition on a fiber base material is laminated to obtain a laminated board. Is manufactured by forming a circuit on the surface thereof.

  Usually, when manufacturing a laminated board, a copper foil is piled up on a structure to make a copper-clad laminated board, and this copper foil is etched to form a circuit.

  In the manufacturing process of a printed wiring board (hereinafter referred to as a wiring board), there is usually a process of forming a solder resist (hereinafter referred to as a resist). Resist protects the surface of the wiring board and prevents unnecessary, such as prevention of short-circuits due to solder bridges between lines during soldering, improvement of connection reliability between component legs and circuits, surface protection of printed wiring boards, prevention of insulation deterioration, etc. It is formed for the purpose of preventing solder from adhering to the location. Recently, photosensitive materials have been widely used as resist materials. In the step of forming a resist using a photosensitive resist material, there is an exposure step of irradiating ultraviolet rays after forming a layer of the resist material on the surface of the wiring board. In most cases, the wiring board is a double-sided wiring board having circuits on both sides, and in this case, a resist is also formed on both sides. In order to efficiently form a resist on such a double-sided wiring board, double-sided simultaneous exposure is performed. However, as the wiring board becomes thinner, so-called back fogging may occur in which the irradiated ultraviolet rays pass through the wiring board and sensitize the resist material on the opposite surface.

  In order to solve the above problems, conventional methods use 1- (phenyl) -3- (4-tert-butyl-styryl) -5- (4-tert-butyl-phenyl)-as an ultraviolet shielding agent. It has been proposed to prepare a prepreg by blending pyrazoline in a thermosetting resin composition, and to produce a laminate by heating and pressurizing a structure containing at least one prepreg (for example, Patent Document 1). reference). However, the above 1- (phenyl) -3- (4-tert-butyl-styryl) -5- (4-tert-butyl-phenyl) -pyrazoline has poor solubility when used as a varnish, and has an ultraviolet shielding property. Not enough. For this reason, for example, when double-sided simultaneous exposure is performed when producing a thin wiring board having a total thickness of 0.5 mm or less, double-sided simultaneous exposure may occur when such double-sided exposure is performed. I could not.

Moreover, in order to improve ultraviolet shielding property, when a ultraviolet shielding agent is mix | blended with a thermosetting resin composition in large quantities, the glass transition temperature (Tg), heat resistance, etc. of a wiring board may fall.
Japanese Patent Laid-Open No. 05-152697

  An object of the present invention is to provide a metal foil with an adhesive layer, which is capable of simultaneous exposure on both sides even when manufacturing a thin wiring board, and is useful for forming a wiring board with reduced heat resistance and Tg, and a metal using the same It is to provide a tension laminate and a printed wiring board.

  The present invention is (1) a metal foil with an adhesive layer comprising a metal foil and an adhesive layer, wherein the adhesive layer contains 0.01 to 5 UV shielding agent with respect to the resin solids constituting the adhesive layer. The present invention relates to a metal foil with an adhesive layer, which contains parts by weight and has a thickness of 10 μm or less.

  The present invention also relates to (2) a metal-clad laminate obtained by laminating a metal foil with an adhesive layer described in (1) above and a prepreg and then heating and pressing.

  The present invention also relates to (3) the metal-clad laminate according to (2), wherein the thickness is 0.2 mm or less.

  The present invention also relates to (4) a printed wiring board obtained by forming a circuit on the metal-clad laminate described in (3).

  The present invention also relates to (5) the printed wiring board according to (4), wherein the total thickness is 0.5 mm or less.

  According to the present invention, a metal foil with an adhesive layer that can be simultaneously exposed on both sides even when manufacturing a thin wiring board and is useful for forming a wiring board with reduced heat resistance and Tg, and a metal using the same A tension laminate and a printed wiring board can be provided.

  The metal foil with an adhesive layer of the present invention is a metal foil with an adhesive layer comprising a metal foil and an adhesive layer. In the present invention, in order to achieve the above object, the content of the ultraviolet shielding agent contained in the adhesive layer and the thickness of the adhesive layer are important. The content of the ultraviolet shielding agent contained in the adhesive layer is 0.01 to 5 parts by weight, preferably 0.1 to 3.0 parts by weight, more preferably 0 with respect to the resin solid content constituting the adhesive layer. 0.5 to 2.0 parts by weight. When the content of the ultraviolet shielding agent is less than 0.01 parts by weight, the ultraviolet shielding is not complete during double-sided simultaneous exposure, and back fogging occurs. When the content exceeds 5 parts by weight, the adhesive layer Since Tg and heat resistance are lowered, Tg and heat resistance as a metal-clad laminate are also lowered.

The adhesive layer has a thickness of 10 μm or less, preferably 1 to 5 μm, more preferably 2 to 4 μm. If the thickness of the adhesive layer exceeds 10 μm, the Tg and heat resistance of the printed wiring board will decrease.
The metal foil used in the present invention is not particularly limited, and examples thereof include a copper foil, a nickel foil, and an aluminum foil. Among these, a copper foil is preferable, and an electric field copper foil or a rolled copper foil is more preferable. In the present invention, a peelable metal foil, an etchable metal foil having an aluminum carrier or a nickel carrier, or the like can also be used.

  Furthermore, the metal foil generally used for printed wiring boards has been subjected to a roughening treatment, but in the present invention, such a metal foil can be used and even if the roughening treatment is not performed. There is no problem.

The metal foil used in the present invention is preferably subjected to a rust prevention treatment performed on the resin bonding surface of a general metal foil. The antirust treatment can be performed using any one of nickel, tin, zinc, chromium, molybdenum, cobalt, or an alloy thereof, but it is preferable to use at least one selected from zinc and chromium. The amount of metal used for the rust prevention treatment varies depending on the type of metal, but is preferably 10 to 2000 μg / dm ^{2 in} total. If the rust preventive treatment is too thick, it tends to cause etching inhibition and a decrease in electrical characteristics, and if it is too thin, it tends to cause a decrease in peel strength with the resin. Furthermore, if a chromate treatment layer is formed on the rust prevention treatment, it is useful because a reduction in peel strength with the resin can be suppressed.

  In the present invention, it is preferable that a silane coupling agent is further adsorbed on the outermost layer of the metal foil. Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, epoxy-functional silanes such as 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N- Amino-functional silanes such as 2- (aminoethyl) 3-aminopropyltrimethoxysilane and N-2- (aminoethyl) 3-aminopropylmethyldimethoxysilane, vinyltrimethoxysilane, vinylphenyltrimethoxysilane, vinyltris (2 Olefin functional silanes such as -methoxyethoxy) silane, acrylic functional silanes such as 3-acryloxypropyltrimethoxysilane, methacrylic functional silanes such as 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxy Mercapto-functional silanes such as orchids are used. In view of compatibility with an adhesion aid to be applied later, it is desirable to have an epoxy group or amino group in the molecule. These may be used alone or in combination.

In the present invention, the thickness of the metal foil is not particularly limited, and a metal foil having a thickness of 105 μm or less generally used for a printed wiring board is used.
The adhesive layer of the present invention is formed from an adhesive containing an ultraviolet shielding agent.

The ultraviolet shielding agent used in the present invention is not limited as long as it can absorb ultraviolet rays having the wavelength used for resist exposure. In this invention, the ultraviolet shielding agent absorbs ultraviolet rays and emits fluorescence. Contains fluorescent dye. Examples of the ultraviolet shielding agent include coumarin, pyrazoline, and pyrrolidine, and specific examples include hydroxybenzophenones, hydroxybenzotriazoles, diaminostyrylbenzyl sulfonic acid derivatives, imidazole derivatives, and coumarin derivatives. Such as 2-hydroxy-4-octoxybenzophenone, 2- (2-hydroxy-5-methyl-phenyl) benzotriazole, 4-methyl-7-diethylaminocoumarin, bis- (1,5-diphenyl) Organic UV screening agents such as -pyrazolin-3-yl) -styrene, 1- (phenyl) -3--3- (4-tert-butyl-styryl) -5- (4-tert-butyl-phenyl) -pyrazoline Can be mentioned. These may be used alone or in combination of two or more. Moreover, you may use a black azine complex, a carbon pigment, an azo dye, etc. For example, as a commercial product, the azine complex is preferably Chuo Synthetic Chemical Co., Ltd., trade name Chuo Black F5, and the disazo dye is Chuo Synthetic Chemical Co., Ltd., trade name Chuo Sudan Black 141. Used for.
In the present invention, an inorganic ultraviolet shielding agent can be used in combination with the organic ultraviolet shielding agent. Examples of the inorganic ultraviolet shielding agent include titanium oxide, clay, talc, aluminum hydroxide, wollastonite, magnesium hydroxide alumina, calcium aluminate, calcium carbonate and the like.

  The adhesive used in the present invention is preferably a thermosetting resin composition. Such a thermosetting resin composition preferably contains (A) an epoxy resin, (B) a polymer component, (C) an epoxy resin curing agent, and (D) a curing accelerator. Further, the adhesive may contain (E) a phosphorus-based flame retardant and (F) an inorganic filler as desired.

The (A) epoxy resin used in the present invention is not particularly limited as long as it is a compound having two or more epoxy groups in the molecule, but bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, tetra Methyl biphenyl type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolak type epoxy resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, dicyclopentadiene-phenol addition reaction type epoxy resin, Phenol aralkyl type epoxy resin, naphthol novolak type epoxy resin, naphthol aralkyl type epoxy resin, naphthol-phenol co-condensed novolac type epoxy resin, naphthol-cresol co-condensed novola Type epoxy resin, aromatic hydrocarbon formaldehyde resin-modified phenol resin type epoxy resin, a biphenyl novolak type epoxy resins. These epoxy resins may be used individually by 1 type, and may be used in combination of 2 or more type. Among these epoxy resins, novolak type epoxy resins are preferable, and novolak type epoxy resins having a biphenyl structure are more preferable. The novolak type epoxy resin having a biphenyl structure refers to a novolak type epoxy resin containing an aromatic ring of a biphenyl derivative in the molecule, and examples thereof include an epoxy resin represented by the general formula (1).

  In general formula (1), p shows 1-5. Commercially available products include Nippon Kayaku Co., Ltd., trade name NC-3000S [epoxy resin of general formula (1) where p is 1.7], NC-3000S-H (general formula where p is 2.8 ( 1) epoxy resin).

  In the present invention, the (A) epoxy resin can be used in combination with a rubber-modified epoxy resin. The rubber-modified epoxy resin can be used without particular limitation as long as it is a product that is commercially available for adhesives or paints. For example, EPICLON TSR-960 (trade name, manufactured by Dainippon Ink Co., Ltd.), EPOTOOHTO YR -102 (trade name, manufactured by Toto Kasei Co., Ltd.), Sumiepoxy ESC-500 (trade name, manufactured by Sumitomo Chemical Co., Ltd.), and the like. These rubber-modified epoxy resins may be used alone or in combination of two or more. The content of the rubber-modified epoxy resin to be used in combination is preferably 10 to 80% by weight of the total amount of epoxy resin, and 30 to 70% by weight because the elongation at curing is increased and the adhesion to the copper foil surface is improved. % Is more preferable. When the content of the rubber-modified epoxy resin is less than 10% by weight, the combined effect tends to be insufficient, and when it exceeds 80% by weight, the heat resistance tends to be inferior.

  The polymer component (B) used in the present invention is preferably a resin composed of at least one selected from crosslinked rubber particles, polyvinyl acetal resin, carboxylic acid-modified polyvinyl acetal resin and the like.

  The crosslinked rubber particles are more preferably composed of one or more kinds of particles selected from the group consisting of acrylonitrile butadiene rubber particles, carboxylic acid-modified acrylonitrile butadiene rubber particles, and butadiene rubber-acrylic resin core-shell particles. Acrylonitrile butadiene rubber particles are obtained by copolymerizing acrylonitrile and butadiene, and partially cross-linking at the stage of copolymerization. Further, at the stage of the copolymerization, carboxylic acid-modified acrylonitrile butadiene rubber particles can be obtained by copolymerizing together carboxylic acids such as acrylic acid and methacrylic acid. The core-shell particles of butadiene rubber-acrylic resin are obtained by a two-stage polymerization method in which butadiene particles are polymerized by emulsion polymerization, followed by addition of a monomer that is a raw material for acrylic resin such as acrylic acid ester and acrylic acid. Can do. The size of the particles can be 50 nm to 1 μm as the primary average particle size. You may use these individually by 1 type or in combination of 2 or more types. Examples of commercially available products of acrylonitrile butadiene rubber particles include XER-81 (trade name) manufactured by Nippon Synthetic Rubber Co., Ltd. Examples of commercially available products of carboxylic acid-modified acrylonitrile butadiene rubber particles include those manufactured by Nippon Synthetic Rubber Co., Ltd. XER-91 (trade name) may be mentioned. Examples of the core-shell particles of butadiene rubber-acrylic resin include EXL-2655 manufactured by Kureha Chemical Industry Co., Ltd. and AC-3832 (trade name) of Takeda Pharmaceutical Company Limited.

  As a polyvinyl acetal resin, the kind, the amount of hydroxyl groups, and the amount of acetyl groups are not particularly limited, but those having a number average polymerization degree of 1000 to 2500 are preferred. Within this range, the solder heat resistance can be further secured, and the viscosity and handling properties of the varnish are further improved. Here, the number average degree of polymerization of the polyvinyl acetal resin can be determined, for example, from the number average molecular weight of polyvinyl acetate as a raw material (measured using a standard polystyrene calibration curve by gel permeation chromatography).

  As the carboxylic acid-modified polyvinyl acetal resin, those obtained by modifying a polyvinyl acetal resin with a carboxylic acid by a conventional method can be used. As for the carboxylic acid-modified polo vinyl acetal resin, those having a number average polymerization degree of 1000 to 2500 are preferred for the same reason as the polyvinyl acetal resin.

  The polyvinyl acetal resin and the carboxylic acid-modified polyvinyl acetal resin may be synthesized by a conventional method, or commercially available products may be obtained. Examples of commercially available products include Sekisui Chemical Co., Ltd., trade names, ESREC BX-1, BX-2, BX-5, BX-55, BX-7, BH-3, BH-S, and KS-3Z. KS-5, KS-5Z, KS-8, KS23Z, manufactured by Denki Kagaku Kogyo Co., Ltd., trade names, electrified butyral 4000-2, 5000A, 6000C, 6000EP, and the like can be used. These resins can be used alone or in admixture of two or more.

  (B) Content of a high molecular component becomes like this. Preferably it is 0.5-25 weight part with respect to the resin solid content which comprises an adhesive bond layer, More preferably, it is 3.0-15 weight part. When the content of the polymer component (B) is less than 0.5 parts by weight, the peel strength or the peel strength of electroless plating after chemical roughening tends to be low, and when it exceeds 25 parts by weight , Solder heat resistance and insulation reliability tend to decrease. In particular, it is more preferable to use the crosslinked rubber particles and the polyvinyl acetal resin in an amount of 1 part by weight or more because the peel strength of the metal foil and the peel strength of the electroless plating after chemical roughening are improved.

  The (C) epoxy resin curing agent used in the present invention is preferably a novolac type phenol resin, and if it is a triazine ring-containing novolac type phenol resin, the electroless plating after the metal foil peel strength and chemical roughening The peel strength of the resin is improved, which is more preferable. The triazine ring-containing novolak type phenol resin is a novolac type phenol resin having a triazine ring in the main chain of the novolak type phenol resin, and may be a cresol novolac type phenol resin having a triazine ring.

  The nitrogen content in the molecule of the triazine ring-containing novolak type phenol resin is preferably 10 to 25% by weight, more preferably 12 to 19% by weight. If the nitrogen content in the molecule is in this range, the dielectric loss does not become too large, and when the adhesive is used as a varnish, the solubility in the solvent is appropriate, and the residual amount of undissolved material can be suppressed. It becomes easy. As the triazine ring-containing novolac type phenol resin, those having a number average molecular weight of 500 to 600 can be suitably used. These may be used alone or in combination of two or more. The triazine ring-containing novolak type phenol resin can be obtained by reacting phenol, aldehyde, and a triazine ring-containing compound under a pH of 5 to 9 by a conventional method. As the triazine ring-containing compound, melamine, guanamine and derivatives thereof, cyanuric acid and derivatives thereof, and the like can be used. When cresol is used instead of the raw material phenol, a triazine ring-containing cresol novolac type phenol resin is obtained. As the cresol, any of o-, m-, and p-cresol can be used.

  Commercially available products of the triazine ring-containing novolak type phenol resin include Dainippon Ink and Chemicals, Inc., trade name triazine ring-containing cresol novolac type phenol resin phenolite LA-3018 (nitrogen content 18% by weight).

(C) The content of the epoxy resin curing agent is such that the ratio of the hydroxyl equivalent of the curing agent to the epoxy equivalent of (A) the epoxy resin is 0.7 to 1.3, more preferably 0.9 to 1.1. It is. When the content of the epoxy curing agent is (A) the ratio of the hydroxyl equivalent of the curing agent to the epoxy equivalent of the epoxy resin is less than 0.7, or exceeds 1.3, the degree of cure of the resin is significantly reduced. , Heat resistance tends to decrease.
The (D) curing accelerator used in the present invention preferably contains various imidazoles and BF ₃ amine complexes which are latent thermosetting agents. 2-phenylimidazole, 2-ethyl-4-methylimidazole, and 1-cyanoethyl-2-phenylimidazolium trimellitate are available from the viewpoints of storage stability of the adhesive, handleability at the B-stage and solder heat resistance. preferable.

  (D) Content of a hardening accelerator becomes like this. Preferably it is 0.1-5 weight part with respect to 100 weight part of (A) epoxy resins, More preferably, it is 0.3-1 weight part. When the content of the curing agent is within the above numerical range, sufficient solder heat resistance, good storage stability of the adhesive, and good handleability when using the B stage are easily obtained.

Further, in the present invention, in order to improve the flame retardancy, the adhesive can contain (E) a flame retardant. Examples of flame retardants include bromine compounds such as decabromodiphenyl ether, tetrabromobisphenol A, tetrabromophthalic anhydride, tribromophenol, triphenyl phosphate, tricresyl phosphate, trixyl phosphate, cresyl diphenyl phosphate, etc. Known metal compounds such as phosphorus compounds, magnesium hydroxide and aluminum hydroxide, red phosphorus and its modified products, antimony compounds such as antimony trioxide and antimony pentoxide, and triazine compounds such as melamine, cyanuric acid and melamine cyanurate Conventional flame retardants can be used. Among these, phosphorus-based flame retardants are preferably used, and particularly phenolic hydroxyl group-containing phosphorus compounds represented by the following general formula (2) are more preferably used.

In the formula, when n is 1, R ₄ is a hydrogen atom, a linear or branched alkyl group, a cycloalkyl group, an aryl group, or an aralkyl group, and when n is 2, each R ₄ Is independently a hydrogen atom, a linear or branched alkyl group, a cycloalkyl group, an aryl group or an aralkyl group, or two R _{4 s} together with the carbon atom to which each is attached. A benzene ring which is unsubstituted or substituted with an alkyl group or a cycloalkyl group, and x is a natural number of 2 or more. These phenolic hydroxyl group-containing phosphorus compounds may be used alone or in combination of two or more.

In the general formula (2), when R ₄ is a linear or branched alkyl group, a C ₁ -C ₆ alkyl group is preferable, and when it is a cycloalkyl group, a C ₆ -C ₈ cycloalkyl group is preferable. In the case of an aryl group, a phenyl group is preferable, and in the case of an aralkyl, a C _{7 to} C ₁₀ aralkyl group is preferable. x is preferably 2.

In the general formula (2), n is 2, and two R _{4 s} , together with the carbon atoms to which each is bonded, are unsubstituted or substituted with an alkyl group or a cycloalkyl group. When a ring is formed, a benzene ring which is unsubstituted or substituted with a C _{1 to} C ₄ alkyl group or a C _{6 to} C ₈ cycloalkyl group is preferable.

Specifically, the phosphorus compound shown by General formula (3) or General formula (4) is mentioned.

Or

In the formula, R ₅ represents a hydrogen atom, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl group, or cyclohexyl group.

  In particular, 10- (2,5-dihydroxyphenyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and derivatives thereof are preferred. As a commercial item, Sanko Co., Ltd. make and brand name HCA-HQ are mentioned.

  The content of the phosphorus-based flame retardant is preferably 1.5 to 3.5% by weight, more preferably 1.8 to 2.% in terms of phosphorus atoms in the total weight of the components (A) to (D). 5% by weight. If the content of the phosphorus flame retardant is in the above range, the flame retardancy is good, the insulation reliability is excellent, and the Tg of the cured coating film is not too low.

  Furthermore, in this invention, in order to improve reliability, the adhesive can contain (F) inorganic filler. (F) The inorganic filler is not particularly limited, and examples thereof include silica, fused silica, talc, alumina, aluminum hydroxide, barium sulfate, calcium hydroxide, aerosil, and calcium carbonate. (F) Inorganic fillers include those treated with various coupling agents such as silane coupling agents for the purpose of enhancing dispersibility. These inorganic fillers may be used alone or in combination of two or more. Silica is preferred from the viewpoint of dielectric properties and low thermal expansion.

  (F) The content of the inorganic filler is preferably 5 to 35% by volume, more preferably 10 to 30% by volume, in the total volume of the components (A) to (D). If the content of the inorganic filler is in the above range, the thermal expansion coefficient and the dielectric loss are not increased, and a sufficient flow can be easily obtained for forming the insulating layer on the inner layer circuit. In order to disperse the inorganic filler in the adhesive used in the present invention, a known kneading method such as a kneader, a ball mill, a bead mill, or a three roll can be used.

  You may mix | blend additives, such as a pigment, a leveling agent, an antifoamer, and an ion trap agent, with the adhesive agent used for this invention as needed.

  The metal foil with an adhesive layer of the present invention can be produced by a known method. That is, an adhesive containing the above ultraviolet shielding agent or a varnish diluted with a solvent is applied to one side of a metal foil, and then dried and semi-cured to form an adhesive layer on the metal foil. By doing so, a metal foil with an adhesive layer can be obtained. Application | coating can be implemented by a well-known method, for example, can be performed using a kiss coater, a roll coater, a comma coater, a gravure coater etc. The applied thickness is adjusted such that the thickness of the adhesive layer after drying or semi-curing is 10 μm or less. The drying may be performed in a heat drying oven or the like, usually at a temperature of 70 to 250 ° C., preferably 100 to 200 ° C., for 1 to 30 minutes, preferably 3 to 15 minutes. The drying temperature at this time is preferably equal to or higher than the temperature at which the solvent used for the production of the varnish can be volatilized.

  Solvents used for the production of varnish include ketones such as acetone, methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as benzene, xylene and toluene, alcohols such as ethylene glycol monoethyl ether, and ethyl ethoxypropionate. Examples thereof include amides such as esters, N, N-dimethylformamide, N, N-dimethylacetamide and the like. These solvents may be used alone or in combination of two or more. There is no restriction | limiting in particular in the usage-amount of the solvent with respect to an adhesive agent, It can be set as the quantity currently used conventionally. For example, when the varnish is applied to the metal foil using a comma coater or a gravure coater, it is preferable to adjust the amount of the solvent used so that the total solid content of the adhesive is 10 to 30% by weight.

  The metal-clad laminate of the present invention can be obtained by laminating the above metal foil with an adhesive layer and a prepreg and heating and pressing. For example, the metal foil with an adhesive layer is laminated on at least one surface of a prepreg so that the adhesive layer of the metal foil with an adhesive layer is in contact with it to obtain a laminate, and the laminate is heated and pressed. Is obtained. As the prepreg, a polyimide resin, an epoxy resin, a phenol resin, or a mixture thereof and a material prepared by impregnating a base material such as glass fiber or organic fiber with a curing agent of each resin is used. be able to.

  Next, a plurality of prepared prepregs are preferably stacked, and the metal foil with the adhesive layer is adhered to the prepreg so that the adhesive layer is in contact with the prepreg. A metal-clad laminate is formed by pressure forming. The heating in this case can be carried out preferably at a temperature of 150 to 250 ° C., and the pressurization can be carried out preferably at a pressure of 0.5 to 10.0 MPa. Heating and pressing are preferably performed simultaneously using a vacuum press or the like. In this case, by performing these treatments for 30 minutes to 10 hours, the adhesive layer (cured layer) and the prepreg are sufficiently cured. Laminates can be manufactured. The metal foil with an adhesive layer may be applied to only one side of the prepreg, or may be applied to both sides to produce a double-sided metal-clad laminate.

  The effective thickness of the metal-clad laminate in the present invention is preferably 0.2 mm or less, more preferably 0.1 mm or less.

  The printed wiring board of the present invention can be obtained by forming a circuit on the metal-clad laminate. That is, the metal-clad laminate is obtained by drilling or metal plating by a known method and then processing the metal foil into a circuit by etching.

  Moreover, a multilayer printed wiring board can be formed using this printed wiring board as an inner layer core substrate. First, one layer or a plurality of layers of the above-described prepreg are laminated on one or both sides of an inner layer core substrate that is the printed wiring board, and a metal foil is disposed on the prepreg layer. Or you may arrange | position the metal foil with an adhesive layer which concerns on this invention on the layer of a prepreg so that an adhesive bond layer may contact | connect a prepreg. Then, the obtained laminate can be heat-pressed and subjected to drilling or metal plating, and then the outermost metal foil can be processed into a circuit shape to obtain a multilayer printed wiring board.

  The total thickness of the effective printed wiring board in the present invention is preferably 0.5 mm or less, more preferably 0.3 mm or less.

Example 1
(1) Preparation of resin varnish for adhesive layer (A) 60 parts by weight of a novolak type epoxy resin having a biphenyl structure as a component (manufactured by Nippon Kayaku Co., Ltd., trade name NC3000-H), Acid-modified polyvinyl acetal resin KS-23Z [manufactured by Sekisui Chemical Co., Ltd., trade name KS-23Z] 15 parts by weight, (C) Triazine ring-containing cresol novolac type phenol resin [nitrogen content 18%, hydroxyl group equivalent 151 Manufactured by Dainippon Ink & Chemicals, Inc., trade name Phenolite LA-3018] 24 parts by weight (epoxy equivalent / hydroxyl equivalent = 1.0), (D) imidazole derivative compound 1-cyanoethyl-2-phenylimidazolium as component Trimellitate [trade name 2PZ-CNS, manufactured by Shikoku Kasei Kogyo Co., Ltd.] 0.3 parts by weight as an ultraviolet shielding agent After blending 1 part by weight of an azine complex [manufactured by Chuo Synthetic Chemical Co., Ltd., trade name Chuo Black F5], a resin composition was obtained, and then methyl ethyl ketone was blended so that the solid content of the varnish was 20%. A resin varnish for the agent layer was prepared.
(2) Production of metal foil with adhesive layer The above adhesion to the adhesive surface (M surface) of an electrolytic copper foil (Furukawa Circuit Foil, trade name F0-WS12, Rz = 1.2 μm) having a width of 510 mm and a thickness of 12 μm The resin varnish for the agent layer was applied, and dried for about 10 minutes at 160 ° C. so that the residual solvent amount after application was 5% by weight or less to prepare a metal foil with an adhesive layer. The thickness of the adhesive layer of the metal foil with the adhesive layer was 3.0 μm.

(3) Production of metal-clad laminate On both sides of a glass cloth substrate high Tg epoxy resin prepreg (manufactured by Hitachi Chemical Co., Ltd., trade name GEA-679FG, thickness 0.04 mm), the metal foil with the adhesive layer A metal foil with an adhesive layer was laminated so that the adhesive layer was in contact, and press molded at 180 ° C. and 3.0 MPa for 1 hour to prepare a double-sided metal-clad laminate.

Example 2
In the production of the resin varnish for the adhesive layer of Example 1 (1), the same material as in Example 1 (1) was used except that the blending amount of Choo Black F5 was 5 parts by weight. A varnish was produced, and a metal foil with an adhesive layer was produced through the same steps as in Example 1 (2). The thickness of the adhesive layer of the metal foil with the adhesive layer was 3.0 μm. Next, a double-sided metal-clad laminate was produced through the same steps as in Example 1 (3).

Example 3
Similar to Example 1 (2), except that the resin varnish for adhesive layer prepared in Example 1 (1) was used and the resin varnish for adhesive layer was applied so that the thickness of the adhesive layer became 10 μm. A metal foil with an adhesive layer was produced through the steps. Next, a double-sided metal-clad laminate was produced through the same steps as in Example 1 (3).

Example 4
A resin varnish for an adhesive layer was prepared through the same steps as in Example 1 (1) except that a prepreg having a thickness of 0.15 mm was used in Example 1 (3), and through the same steps as in (2). A metal foil with an adhesive layer was prepared. Next, a double-sided metal-clad laminate was produced through the same steps as in Example 1 (3).

Example 5
In the production of the resin varnish for the adhesive layer of Example 1 (1), except that 1 part by weight of Chuo Sudan Black 141 (disazo dye: manufactured by Chuo Synthetic Chemical Co., Ltd.) was used instead of Chuo Black F5. Produced a resin varnish for an adhesive layer using the same material as in Example 1 (1), and produced a metal foil with an adhesive layer through the same steps as in Example 1 (2). The thickness of the adhesive layer of the metal foil with the adhesive layer was 3.0 μm. Next, a double-sided metal-clad laminate was produced through the same steps as in Example 1 (3).

Comparative Example 1
A glass cloth base high Tg epoxy resin prepreg (manufactured by Hitachi Chemical Co., Ltd., trade name GEA-679FG, thickness 0.04 mm), an electrolytic copper foil (Furukawa Circuit Foil Co., Ltd.) having an upper width of 510 mm and a thickness of 12 μm. (Trade name F0-WS12, Rz = 1.2 μm) was laminated and press-molded under conditions of 180 ° C. and 3.0 MPa for 1 hour to prepare a double-sided metal-clad laminate.

Comparative Example 2
In the production of the resin varnish for the adhesive layer of Example 1 (1), the same material as in Example 1 (1) was used except that the amount of Choo Black F5 was 0.005 parts by weight. A resin varnish was prepared, and a metal foil with an adhesive layer was prepared through the same steps as in Example 1 (2). The thickness of the adhesive layer of the metal foil with the adhesive layer was 3.0 μm. Next, a double-sided metal-clad laminate was produced through the same steps as in Example 1 (3).

Comparative Example 3
In the production of the resin varnish for the adhesive layer of Example 1 (1), the same material as in Example 1 (1) was used except that the blending amount of Choo Black F5 was 20 parts by weight. A varnish was produced, and a metal foil with an adhesive layer was produced through the same steps as in Example 1 (2). The thickness of the adhesive layer of the metal foil with the adhesive layer was 3.0 μm. Next, a double-sided metal-clad laminate was produced through the same steps as in Example 1 (3).

Comparative Example 4
Similar to Example 1 (2) except that the adhesive varnish resin varnish was applied so that the thickness of the adhesive layer was 30 μm using the adhesive varnish resin varnish produced in Example 1 (1). A metal foil with an adhesive layer was produced through the steps. Next, a double-sided metal-clad laminate was produced through the same steps as in Example 1 (3).

  Evaluation of the double-sided metal-clad laminate produced in Examples 1-5 and Comparative Examples 1-4 was performed as follows. The results are shown in Table 1.

[Measurement of glass transition temperature (Tg)]
The Tg of the produced double-sided metal-clad laminate was measured by a thermomechanical analysis method (TMA method) manufactured by DuPont.

(Evaluation of solder heat resistance)
The solder heat resistance of the double-sided metal-clad laminate was immersed in a solder bath at 288 ° C. for 20 seconds after moisture absorption treatment (PCT treatment: 121 ° C., kept in a pressure cooker treatment device of 2.13 × 10 ⁵ Pa for 3 hours). It is the result of observing a double-sided metal-clad laminate. Each symbol means ◯: no change, Δ: occurrence of measling, ×: occurrence of blistering, and three symbols respectively show the results of evaluation using three test pieces.

(Confirmation of the presence of back cover by simultaneous exposure on both sides)
Etching was performed on the double-sided metal-clad laminate to form a circuit, thereby producing a double-sided wiring board. A resist material (manufactured by Taiyo Ink Manufacturing Co., Ltd., trade name: PSR-400) is applied to both sides of the produced double-sided wiring board, dried, and then passed through a mask film through an ultraviolet irradiation device (manufactured by Oak Manufacturing Co., Ltd., product). No. HMW-532D) was exposed by irradiating with 500 mJ / cm ² ultraviolet rays from both sides, and developed using a sodium carbonate solution to form a resist. And the formed resist was visually observed and the presence or absence of back fogging was confirmed.

  As shown in Table 1, it is clear that the double-sided metal-clad laminates produced in Examples 1 to 5 have good solder heat resistance and Tg, and no back fogging due to double-sided simultaneous exposure. In contrast, the double-sided metal-clad laminate produced in Comparative Examples 1 and 2 had good heat resistance and Tg, but back fogging occurred. Further, the double-sided metal-clad laminates produced in Comparative Examples 3 and 4 did not cause back fogging, but the heat resistance and Tg were significantly reduced.

Claims (5)

It is metal foil with an adhesive layer provided with metal foil and an adhesive layer, Comprising: The said adhesive layer contains 0.01-5 weight part of ultraviolet shielding agents with respect to 100 weight part of resin solid content which comprises an adhesive bond layer. A metal foil with an adhesive layer, wherein the thickness is 10 μm or less.   A metal-clad laminate obtained by laminating the metal foil with an adhesive layer according to claim 1 and a prepreg and heating and pressing.   The metal-clad laminate according to claim 2, wherein the thickness is 0.2 mm or less.   A printed wiring board obtained by forming a circuit on the metal-clad laminate according to claim 3.   The printed wiring board according to claim 4, wherein the total thickness is 0.5 mm or less.