TWI478810B - An insulating resin sheet, and a multilayer printed circuit board using the same - Google Patents

Description

Insulating resin sheet and method of manufacturing multilayer printed circuit board using the same

The present invention relates to an insulating resin sheet useful for forming an insulating layer of a multilayer printed wiring board, and a method of manufacturing a multilayer printed wiring board using the insulating resin sheet.

In the past, as a manufacturing technique of a multilayer printed wiring board, a manufacturing method in which an insulating layer and a conductor layer are alternately overlapped on a core substrate is known. In the formation of the insulating layer, the adhesive film is mainly used for forming a film of a thermosetting resin layer on the plastic film, and the film is laminated on the inner layer circuit board to peel off the plastic film, and then the thermosetting resin is heated. Hardened to form an insulating layer. On the other hand, in recent years, in the multilayer printed circuit board, for the miniaturization of the electronic device or the electronic component, for example, it is required to gradually reduce the thickness of the core substrate or to omit it. In order to achieve the thinning of such a multilayer printed circuit board, in order to maintain the mechanical strength of the multilayer printed circuit board, it is considered that the use of the prepreg can be effectively achieved as a material for forming the interlayer insulating layer.

For example, Patent Document 1 and Patent Document 2 disclose a B-stage resin composition sheet in which a resin composition layer for addition is formed on one surface of a prepreg.

[Patent Document 1] JP-A-2003-249764

[Patent Document 2] JP-A-2003-313324

When the prepreg is used for the interlayer insulating layer, the prepreg surface is formed by laminating or thermally hardening the inner layer circuit substrate by the flow of the resin composition impregnated in the prepreg or the expansion of the glass cloth. The resin composition layer is thinned. Therefore, when the conductor layer is formed by plating, the surface of the insulating layer is roughened by an oxidizing agent or the like, and the fibrous sheet substrate in the prepreg is exposed. In the method of manufacturing a multilayer printed wiring board of the construction method, the present inventors attempted to use the thermosetting resin composition layer described in Patent Documents 1 and 2 to laminate the insulating resin on one side of the prepreg. Sheet. In other words, when the insulating resin sheet is laminated on the inner layer circuit board by a vacuum laminator, it is found that the insulating resin sheet can sufficiently follow the circuit unevenness of the inner layer circuit board, and the mounting property of the circuit unevenness is also good. On the other hand, it has been found that the laminated insulating resin sheet reflects the unevenness of the circuit of the inner layer circuit board, and the surface is formed into an uneven shape. Therefore, in order to smooth the surface of the insulating resin sheet, the insulating resin sheet is heated and pressurized by a metal plate under normal pressure, and when the surface is smoothed, the thermosetting resin composition layer on the surface of the insulating resin sheet flows, reflecting The unevenness of the circuit causes a thinning of the thickness of a part of the thermosetting resin composition layer. Further, it has been found that after the insulating resin sheet is thermally cured to form an insulating layer, the surface of the insulating layer is roughened, and when the conductor layer is formed by plating, the fibrous sheet substrate of the prepreg is exposed by the portion having a reduced thickness. Improper formation of the conductor layer.

Therefore, an object of the present invention is to provide an insulating resin sheet having a fibrous sheet substrate which does not cause the problem of the above-mentioned fibrous sheet substrate to be exposed when the multilayer printed wiring board is produced.

The inventors of the present invention have found that the insulating resin sheet made of the cured layer of the thermosetting resin composition and the prepreg layer is used for the production of a multilayer printed wiring board, even if it is insulated. In the case where the surface of the layer is roughened, the exposure of the fibrous sheet substrate as described above can be suppressed, and the present invention has been completed.

That is, the present invention is intended to contain the following.

[1] An insulating resin sheet having a cured layer of a thermosetting resin composition on one side of a prepreg.

[2] The insulating resin sheet according to the above [1], further comprising a support layer on the cured layer.

[3] The cured product sheet of the cured layer of the thermosetting resin composition is formed on the support, and the insulating resin sheet according to the above [2] is obtained on one surface of the prepreg.

[4] The insulating resin sheet according to the above [2] or [3], which is subjected to release treatment on the side of the cured layer of the support layer.

[5] The insulating resin sheet according to any one of the above [2] to [4], wherein the support layer is a plastic film.

[6] The insulating resin sheet according to any one of the above [1] to [5], wherein the prepreg surface of the insulating resin sheet is protected by a protective film.

[7] The insulating resin sheet according to any one of the above [1] to [6], wherein the thickness of the prepreg is from 10 to 70 μm.

[8] The insulating resin sheet according to any one of the above [1] to [7], wherein the hardened layer of the thermosetting resin composition is 1 to 30 μm.

[9] It is used for (1) mounting an insulating resin sheet on a double-sided or single-sided surface of a circuit board under a circuit board, and heating and pressurizing the elastic material under pressure reduction to perform lamination on the circuit board. a step of laminating, (2) a step of smoothing the insulating resin sheet by heating and pressurizing the laminated insulating resin sheet by a metal plate or a metal roll, and (3) smoothing the smoothed The insulating resin sheet according to any one of the above [1] to [8], wherein the insulating resin sheet is subjected to a heat-hardening step.

[10] The insulating resin sheet according to the above [9], which has substantially no fluidity in the layering step and the smoothing step of the cured layer of the thermosetting resin composition.

[11] A multilayer printed wiring board in which an insulating layer is formed of the insulating resin sheet according to any one of the above [1] to [10].

[12] The insulating resin sheet according to any one of the above [1] to [10] is provided on the inner layer circuit board, and the prepreg layer is bonded to the double-sided or single-sided side of the inner layer circuit board. a step of laminating the inner layer circuit substrate by heating and pressurizing the elastic material under reduced pressure, and (2) heating the laminated insulating resin sheet by a metal plate or a metal roll And a step of smoothing the pressurization step and (3) a method of producing a multilayer printed wiring board in which the smoothed insulating resin sheet is thermally hardened.

[13] The heating and pressurization of the insulating resin sheet in the laminating step and the smoothing step is the method described in the above [12] on the support layer.

[14] further comprising a step of punching holes in the insulating layer, a roughening step of roughening the insulating layer, a plating step of forming a conductor layer on the surface of the roughened insulating layer by plating, and The method described in the above [12] or [13] of the circuit forming step of the conductor layer forming circuit.

[Effects of the Invention]

In the case where the insulating resin sheet of the present invention is laminated on the inner layer circuit board by a vacuum laminator, the insulating resin sheet can sufficiently follow the unevenness of the circuit on the inner layer circuit board, and the inlay of the circuit unevenness is also good. Moreover, when the surface of the insulating resin sheet is smoothed after lamination, the unevenness of the circuit can be reflected to suppress the thickness of the resin composition layer from becoming thin. Therefore, after the insulating layer is formed by thermal curing, even if the surface of the insulating layer is roughened, the fiber base material of the prepreg is not exposed, and the formed conductor layer can be smoothly formed, thereby producing a multilayer having high reliability. A printed circuit board.

[Best Mode for Carrying Out the Invention]

Hereinafter, the present invention will be described in detail by way of preferred embodiments.

The prepreg used in the present invention is obtained by impregnating a sheet-like fibrous base material with a thermosetting resin composition and drying it by heating.

The thermosetting resin composition is not particularly limited as long as it can be applied to an insulating layer of a multilayer printed wiring board, and specific examples of the thermosetting resin composition include epoxy resin and cyanate resin. A composition of a thermosetting resin such as a phenol resin, a bismaleimide-imide-triazine resin, a polyimide resin, an acrylic resin, or a vinyl benzyl resin, and a small amount of a curing agent thereof. Among them, a composition containing an epoxy resin as the thermosetting resin is preferable, and for example, a composition containing an epoxy resin, a thermoplastic resin, and a curing agent is preferable.

Examples of the epoxy resin include bisphenol A type epoxy resin, biphenyl type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy resin, bisphenol F type epoxy resin, and phosphorus containing ring. Oxygen resin, bisphenol S type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, phenolic epoxy resin for phenol paint, phenolic epoxy resin for cresol paint, bisphenol A paint Phenolic epoxy resin, epoxy resin having a butadiene structure, diglycidyl ether of bisphenol, diglycidyl ether of naphthalenediol, epoxypropyl etherate of phenol, and alcohol The bis-epoxypropyl etherate, and alkyl substituents, halides, and hydrides of the epoxy resins. These epoxy resins may be used alone or in combination of two or more.

Among the epoxy resins, bisphenol A type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy resin, and the like, from the viewpoints of heat resistance, insulation reliability, and adhesion to a metal film, A biphenyl type epoxy resin or an epoxy resin having a butadiene structure is preferred. Specific examples of the epoxy resin include liquid bisphenol A type epoxy resin ("Epikote 828EL" manufactured by Japan Epoxy Resins Co., Ltd.) and naphthalene type bifunctional epoxy resin (Daily Ink Chemical Industry Co., Ltd.) "HP4032" and "HP4032D"), naphthalene type 4-functional epoxy resin ("HP4700" manufactured by Dainippon Ink Chemicals Co., Ltd.), and naphthol type epoxy resin (ESN-475V manufactured by Eastern Chemicals Co., Ltd.) ), epoxy resin having a butadiene structure ("PB-3600" manufactured by Daicel Chemical Industry Co., Ltd.), epoxy resin having a biphenyl structure ("NC3000H" and "NC3000L" manufactured by Nippon Kayaku Co., Ltd. , Japan Epoxy Resins (shares) "YX4000").

In the thermosetting resin composition, for the purpose of imparting appropriate flexibility to the resin composition after curing, a thermoplastic resin may be added. Examples of the thermoplastic resin include a phenoxy resin, a polyvinyl acetal resin, a polyimine, a polyamidoximine group, a polyether oxime, and a polyfluorene. These thermoplastic resins may be used alone or in combination of two or more. In the thermoplastic resin, when the non-volatile component of the thermosetting resin composition is 100% by mass, it is preferably blended at a ratio of 0.5 to 60% by mass, preferably at a ratio of 3 to 50% by mass.

For example, FX280, FX293, Japan Epoxy Resins, YX8100, YL6954, YL6974, etc., which are manufactured by Toho Kasei Co., Ltd., may be mentioned.

As the polyvinyl acetal resin, a polyvinyl butyral resin is preferable, and as a commercial product of the polyvinyl acetal resin, for example, an electro-chemical industry (s), an electrochemical butyral 4000-2 , 5000-A, 6000-C, 6000-EP, Sekisui Chemical Industry Co., Ltd. S-LECBH series, BX series, KS series, BL series, BM series, etc.

As a commercial product of polyimine, for example, the poly-imine of the Japanese physicochemical company, "Ricaket SN20" and "Ricaker PN20" are mentioned. Further, a linear polyimine obtained by reacting a bifunctional hydroxyl-terminated polybutadiene, a diisocyanate compound, and a tetrabasic acid anhydride (described in JP-A-2006-37083) contains a polyoxane skeleton. Denatured polyimine, such as those described in JP-A-2002-12667, JP-A-2000-319386, and the like.

As a commercial product of a polyamidimide group, for example, Toyobo Co., Ltd. The polyamidimide group "VYLOMAXHR11NN" and "VYLOMAXHR16NN". Further, a denatured polyamidoquinone imine group such as a polyamidolimine group "KS9100" or "KS9300" containing a polyoxyalkylene skeleton manufactured by Hitachi Chemical Co., Ltd. can be used.

For example, a polyether oxime "PES5003P" manufactured by Sumitomo Chemical Co., Ltd., etc., may be mentioned.

For example, the "P1700" and "P3500" manufactured by Solenadvanced Polymers Co., Ltd. may be mentioned as the sale of the sputum.

Examples of the curing agent include an amine curing agent, an lanthanum curing agent, an imidazole curing agent, a phenol curing agent, a naphthol curing agent, an acid anhydride curing agent, or an epoxy addition product or microencapsulation thereof. , cyanate resin, and the like. Among them, a phenolic curing agent, a naphthol-based curing agent, and a cyanate resin are preferred. These hardeners may be used alone or in combination of two or more.

Examples of the phenolic curing agent and the naphthol-based curing agent include MEH-7700, MEH-7810, MEH-7851 (made by Megumi Kasei Co., Ltd.), NHN, CBN, and GPH (Nippon Chemicals Co., Ltd.) )), SN170, SN180, SN190, SN475, SN485, SN495, SN375, SN395 (manufactured by Tohto Kasei Co., Ltd.), LA7052, LA7054, LA3018, LA1356 (manufactured by Dainippon Ink Chemical Industry Co., Ltd.).

Examples of the cyanate resin include bisphenol A dicyanate, polyphenol cyanate (oligo(3-methyl-1,5-phenylene)), 4,4'- Methyl bis(2,6-dimethylphenyl cyanate), 4,4'-ethylene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-double (4-cyanate) phenylpropane, 1,1-bis(4-cyanate phenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3 - 2-functional (4-cyanate phenyl-1-(methylethylidene)) benzene, bis(4-cyanate phenyl) sulfide, bis(4-cyanate phenyl) ether A cyanate resin, a phenolic phenolic phenol, a polyfunctional cyanate resin derived from phenolic phenol or the like, a pre-polymerized triazine-based prepolymer of these cyanate resins, and the like. Specific examples of the cyanate resin include a phenolic polyfunctional cyanate resin for phenol paint ("PT30" manufactured by Lonza Japan Co., Ltd., cyanate equivalent 124) or bisphenol A dicyanate. Some or all of them are triazine-formed into a terpolymer prepolymer ("BA230" manufactured by Lonza Japan Co., Ltd., cyanate equivalent 232).

When the phenolic curing agent or the naphthol-based curing agent is used, the phenolic hydroxyl equivalent of these curing agents is 0.4 to 2.0. The ratio of the range is preferably, and it is preferably a ratio in the range of 0.5 to 1.0. When the cyanate resin is used, the ratio of the cyanate ester equivalent to the range of 0.3 to 3.3 is preferably the ratio of the epoxy equivalent of 1, and the ratio of the range of 0.5 to 2.0 is preferable.

The thermosetting resin composition may further contain a curing accelerator in addition to the curing agent. Examples of the curing accelerator include an imidazole compound and an organic phosphine compound. Specific examples thereof include 2-methylimidazole and triphenylphosphine. When a hardening accelerator is used, it is preferable that the hardening accelerator is used in the range of 0.1 to 3.0% by mass for the epoxy resin. Further, when a cyanate resin is used as the epoxy resin curing agent, in order to shorten the curing time, a system which is used as a curing catalyst may be added to a system in which an epoxy resin composition and a cyanate compound are used in combination. Organometallic compounds. Examples of such an organometallic compound include an organic copper compound such as copper (II) acetamidine acetone, an organic zinc compound such as zinc (II) acetamidine acetone, cobalt (II) acetamidine acetone, cobalt (III) acetamidine acetone, or the like. Organic cobalt compounds, etc. These organometallic compounds may be used alone or in combination of two or more. The amount of the organometallic compound to be added is preferably in the range of 10 to 500 ppm in terms of metal, and preferably in the range of 25 to 200 ppm.

Further, the thermosetting resin composition may contain an inorganic filler in order to lower the thermal expansion of the resin composition after curing. Examples of the inorganic filler include cerium oxide, aluminum oxide, mica, mica, ceric acid salt, barium sulfate, magnesium hydroxide, and titanium oxide. Among them, cerium oxide and aluminum oxide are preferred. Ceria is particularly good. Further, the average particle diameter of the inorganic filler is preferably 3 μm or less from the viewpoint of insulation reliability, and particularly preferably 1.5 μm or less. When the non-volatile content of the thermosetting resin composition is 100% by mass, the content of the inorganic filler is preferably 20 to 60% by mass, and more preferably 20 to 50% by mass.

Further, the thermosetting resin composition may contain other components as necessary. Examples of the other component include an organic phosphorus-based flame retardant, an organic nitrogen-containing phosphorus compound, a nitrogen compound, a siloxane-based flame retardant, and a metal hydroxide; and a siloxane powder, a nylon powder, and a nylon powder. Organic fillers such as fluororesin powder; tackifiers such as Orben and Pantone; polymer defoamers or coating agents such as siloxanes and fluororesins; imidazole, thiazole, triazole, and decane Mixing agent and other adhesion imparting agent; phthalocyanine, blue, phthalocyanine. Coloring agents such as green, iodine, green, diazide yellow, carbon black, and the like.

The flaky fiber base material used for the prepreg is not particularly limited, and for example, a substrate for a prepreg such as a glass cloth, an aromatic polyamide woven fabric, or a liquid crystal polymer nonwoven fabric can be used. In particular, when it is used for forming an insulating layer of a multilayer printed wiring board, it is preferable to use a thin type having a thickness of 50 μm or less, particularly preferably 10 to 40 μm. Specific examples of the sheet-like fibrous base material include a Style 1027 MS manufactured by Asahi-Schwebel Co., Ltd. (having a warp density of 75 pieces/25 mm, a weft density of 75 pieces/25 mm, a cloth weight of 20 g/m ² , and a thickness of 19 μm). ), Style1037MS made by Asahi-Schwebel (warp density 70 pieces / 25mm, weft density 73 pieces / 25mm, cloth weight 24g / m ² , thickness 28μm), (stock) 1037NS made by Ozawa Manufacturing Co., Ltd. (warp density 72 pieces / 25mm , weft density 69 pieces / 25mm, cloth weight 23g / m ² , thickness 21μm), (stock) 1027NS made by Ozawa (the warp density 75 / 25mm, weft density 75 / 25mm, cloth weight 19.5g / m ² , thickness 16μm), (shares) 1015NS made by Ozawa Manufacturing Co., Ltd. (haze density 95 pieces / 25mm, weft density 95 pieces / 25mm, cloth weight 17.5g / m ² , thickness 15μm), (shares) 1000NS made by Ozawa Manufacturing Co., Ltd. (warp density 85 pieces / 25 mm, weft density 85 pieces / 25 mm, cloth weight 11 g / m ² , thickness 10 μm) and the like. Further, examples of the liquid crystal polymer nonwoven fabric include Vecrus (basis weight: 6 to 15 g/m ² ) or Vactran obtained by melt blown of an aromatic polyester nonwoven fabric made of Kuraray.

Glass cloth is widely used as a sheet-like fiber base material. The glass cloth used in the multilayer printed circuit board is generally manufactured by weaving a glass monofilament with tens to hundreds of bundles of yarn by an automatic loom or the like, and generally, when the yarn is bundled into a bundle, the yarn is prevented from being unwound. Raise and crepe. Therefore, in the prepreg, a part of the glass fibers are not arranged equally, and there is a partial overlap. The The overlap of the glass fibers, compared with other parts, the thickness of the glass cloth is large. Further, in the prepreg manufacturing step, the glass cloth is not in the center of the prepreg but is present in the vicinity of the surface due to the relaxation of the glass cloth or the like. In general, the exposure of the sheet-like fibrous base material in the insulating resin sheet is particularly remarkable in that the thickness of the sheet-like fibrous base material is larger than that of the larger portion or a portion of the sheet-like fibrous base material in the vicinity of the surface. .

The prepreg can be produced by a known hot melt method, a solvent method, or the like. In the hot melt method, the resin composition is not dissolved in an organic solvent, and once applied to a release paper having good peelability from the resin composition, the laminate is applied to a sheet-like fibrous substrate or coated by a mold. A method of manufacturing a prepreg after the cloth is directly coated. In addition, the solvent method is a method in which a resin composition varnish is impregnated into a sheet-like fibrous base material by dissolving a resin composition in a resin composition varnish of an organic solvent, and then the resin composition varnish is impregnated into a sheet-like fibrous base material, followed by drying. Further, the film formed of the thermosetting resin composition laminated on the support may be prepared by continuously performing thermal lamination on both sides of the sheet-like reinforcing substrate under heating and pressurization conditions.

Examples of the organic solvent in the preparation of the varnish include ketones such as acetone, methyl ethyl ketone, and cyclohexanone, ethyl acetate, butyl acetate, cellosolve acetate, and propylene glycol monomethyl ether acetate. Acetate such as carbitol acetate, cellosolve, carbitol such as butyl carbitol, aromatic hydrocarbon such as toluene or xylene, dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like. The organic solvent may be used alone or in combination of two or more.

The drying conditions are not particularly limited. However, in order to laminate the inner layer circuit board, the thermosetting resin composition at the temperature in the laminating step must have fluidity and adhesion. Therefore, it is important to harden the hardenable resin composition as much as possible during drying. On the other hand, when a large amount of the organic solvent remains in the prepreg, it may cause swelling after hardening, and it is generally dried to a content ratio of the organic solvent in the thermosetting resin composition of 5% by mass or less, preferably 2 Below mass%. Therefore, the drying conditions are set from these two viewpoints, and the conditions vary depending on the hardenability of the thermosetting resin composition or the amount of the organic solvent in the varnish. For example, a varnish containing 30 to 60% by mass of an organic solvent is generally used. Dry at 80~180 °C for 3~13 minutes. Moreover, the manufacturer can set appropriate and simple drying conditions by simple experiments.

Although the thickness of the prepreg differs depending on the thickness of the conductor layer of the inner circuit board, the thickness of the conductor layer is generally 10 to 30 μm, and the thickness of the prepreg is generally in the range of 10 to 70 μm, which is used as the cost of the glass cloth. From the viewpoint of the desired thinness of the insulating resin sheet, it is preferably 12 to 50 μm, more preferably 12 to 40 μm. Further, the larger the thickness of the prepreg, the more likely the exposure of the fibrous base material is relaxed, but it is disadvantageous for the thickness reduction of the multilayer printed wiring board. The insulating resin sheet of the present invention can simultaneously achieve the reduction of the exposure of the fibrous base material and the reduction in thickness of the multilayer printed wiring board. Further, the thickness of the prepreg can be easily controlled by adjusting the impregnation amount of the thermosetting resin composition. Further, the prepreg must have no voids in the wiring portion of the inner layer circuit board and have laminar fluidity, and the minimum melt viscosity is preferably in the range of 200 to 7000 poise, and particularly preferably in the range of 400 to 3000 poise.

The "hardened layer of the thermosetting resin composition" in the present invention is obtained by thermally curing a thermosetting resin composition. The thermosetting resin composition is only suitable for the insulating layer of the multilayer printed wiring board, and it can be used without particular limitation, and the same as the thermosetting resin composition used for the prepreg described above can be used. Further, the thermosetting resin composition used for the prepreg may be the same as or different from the thermosetting resin composition used for the cured layer.

The cured material layer in the insulating resin sheet of the present invention can be obtained, for example, by a method of thermally curing a thermosetting resin composition which forms a sheet of a thermosetting resin composition layer on a support. In other words, the resin varnish in which the thermosetting resin composition is dissolved in an organic solvent can be applied to the support by a known method, for example, and the resin varnish is applied onto the support, and heated by hot air blowing to dry the organic After the solvent is formed, a thermosetting resin composition layer is formed, and the thermosetting resin composition of the subsequently obtained sheet is thermally cured to obtain a cured product sheet, which is obtained by the step of adhering to the prepreg on one side. The insulating resin sheet of the present invention. Further, in the production of the sheet, the coated resin varnish is applied to the support, and the cured sheet is obtained by simultaneous or successive drying and hardening, and the cured sheet thus obtained is applied to the prepreg by one side. The subsequent step can obtain the insulating resin sheet of the present invention.

Examples of the organic solvent used for the preparation of the resin varnish include ketones such as acetone, methyl ethyl ketone, and cyclohexanone, ethyl acetate, butyl acetate, cellosolve acetate, and propylene glycol monomethyl ether. Acetate such as acid ester or carbitol acetate, cellosolve, carbitol such as butyl carbitol, aromatic hydrocarbon such as toluene or xylene, dimethylformamide, and dimethyl Indoleamine, N-methylpyrrolidone, and the like. Two or more types of organic solvents can be used in combination.

The drying condition in the case of preparing the sheet is not particularly limited, and the content ratio of the organic solvent to the thermosetting resin composition layer is usually 10% by mass or less, preferably 5% by mass or less. Although it varies depending on the amount of the organic solvent in the resin varnish, for example, a resin varnish containing 30 to 60% by mass of an organic solvent can be dried at 50 to 150 ° C for 3 to 10 minutes. The curing conditions in the case where the thermosetting resin composition layer of the subsequent sheet is sequentially cured or the resin varnish applied on the support is dried and hardened at the same time are not particularly limited, and for example, it contains 30 to 60 masses. The varnish of the organic solvent of % is heated at a temperature of 50 to 200 ° C for 10 minutes to 10 hours to form a cured layer. Moreover, for drying and hardening conditions, the manufacturer can set suitable and better conditions by simple experiment.

As the support, a plastic film can be used. In addition to the plastic film, a metal foil such as release paper, copper foil or aluminum foil may be used as the support. Examples of the plastic film include polyethylene terephthalate (hereinafter abbreviated as "PET"), polyester such as polyethylene naphthalate, polycarbonate, acrylic resin, cyclic polyolefin, and triethylene sulfonate. Cellulose, polyether sulfide, polyether ketone, polyimine, and the like. Among them, a polyethylene terephthalate film or a polyethylene naphthalate film is preferred, and an inexpensive polyethylene terephthalate film is preferred. When a plastic film is used in particular, the cured film of the odd self-hardenable resin composition layer is peeled off, and the formed surface of the thermosetting resin composition layer is subjected to mold release treatment. The support of the layer is better. The metal foil can be removed by an etching solution. As the release agent used for the release treatment, only the cured product can be peeled off from the support, and there is no particular limitation. For example, a decane-based release agent, an alkyd-based release agent, and the like can be given. In addition, a commercially available plastic film with a release layer may be used, and as a preferred example, a LIN film made of a PET film having a release layer containing an alkyd resin release agent as a main component may be used. -1, AL-5, AL-7, etc. Further, the plastic film may be subjected to a matting treatment or a corona treatment, and a release layer may be formed on the treated surface. When the copper foil is used as a support, the copper foil can be used as a conductor layer without being peeled off. The thickness of the support is not particularly limited and is generally from 10 to 150 μm, preferably from 25 to 50 μm.

In the cured layer of the insulating resin sheet of the present invention, the thermosetting resin composition does not need to be completely thermally cured, and is only cured to such an extent that the effects of the present invention can be exhibited. That is, it can be used for the formation of a general interlayer insulating layer, and the subsequent sheet formed of the support and the thermosetting resin composition layer must be embedded in a circuit for laminating the inner layer circuit substrate, and must have sufficient flow. The cured layer of the thermosetting resin composition in the insulating resin sheet of the present invention is intended to suppress the exposure of the sheet-like fibrous base material of the prepreg, and has little flow in the laminating step and the smoothing step. Sex is important, and it is preferable to have no liquidity. For example, using a vacuum laminator, the cured layer of the thermosetting resin composition is 12 cm × 15 cm on the FR4 substrate having a thickness of 20 cm square and 0.8 mm, under the same conditions as the actual lamination step and the smoothing step. For lamination and smoothing, the maximum scale leakage length at this time is preferably 0.3 mm or less, more preferably 0.2 mm or less, most preferably 0.1 mm or less, and particularly preferably a hardened state of substantially 0. For example, the maximum scale length measured under the following representative conditions can be used as an index of the degree of hardening of the preferred cured layer used in the present invention. Specifically, a cured layer of a thermosetting resin composition of 12 cm × 15 cm (a rectangular cured layer having a plane size of 12 cm × 15 cm) was subjected to vacuum suction at a temperature of 80 ° C for 30 seconds using a vacuum laminator. °C, pressure 7.0kgf / cm ² conditions, laminated with heat-resistant rubber for 60 seconds, and then used at 9.0 °C under atmospheric pressure using a SUS mirror plate at a temperature of 80 ° C and a pressure of 5.5 kgf / cm ² The maximum scale leakage length of the resin when the smoothing treatment is applied is preferably 0.3 mm or less, more preferably 0.2 mm or less, particularly preferably 0.1 mm or less, particularly preferably substantially 0. .

The degree of hardening of the thermosetting resin composition can also be evaluated by the glass transition temperature. In the present invention, the glass transition temperature at least hardened to the cured product can be observed to a good extent. The adhesive sheet formed of the support and the thermosetting resin composition which is generally used for the interlayer insulating layer has fluidity as described above. For example, even if the thermosetting resin composition layer is in the B stage, the reactivity is remarkably low. The glass transition temperature cannot be measured, and even if it is measurable, it is at least a glass transition temperature of room temperature or lower. Generally, when the temperature is hardened until the glass transition temperature can be observed, in the range of the temperature of the general lamination step and the temperature of the smoothing step (about 70 ° C to 140 ° C), the thermosetting resin composition has substantially no fluidity, Or almost no liquidity. From these points, generally the sheet is clearly distinguishable from the cured sheet of the present invention. The glass transition temperature of the cured product is preferably 80 ° C or higher. Further, the upper limit of the glass transition temperature is not particularly limited, and the glass transition temperature of the generally cured thermosetting resin composition is usually limited to a range of 300 ° C or lower.

The so-called "glass transition temperature" is a value indicating heat resistance. The measurement is determined according to the method described in JIS K 7179, and specifically, it can be measured using thermomechanical analysis (TMA), dynamic mechanical analysis (DMA), or the like. Examples of the thermomechanical analysis (TMA) include TMA-SS6100 (manufactured by Seiko Instruments Co., Ltd.) and TMA-8310 (manufactured by rigaku). For dynamic mechanical analysis (DMA), for example, DMS- 6100 (Seiko Instruments Co., Ltd.) and the like. Further, the glass transition temperature is higher than the decomposition temperature, and when the glass transition temperature is not actually observed, the decomposition temperature can be regarded as the glass transition temperature in the present invention. The decomposition temperature is a temperature at which the mass reduction rate at the time of measurement according to the method described in JIS K 7120 is 5%.

The thickness of the cured layer of the thermosetting resin composition is generally in the range of 1 to 30 μm, preferably 1 to 20 μm. When it is too thin, the production of the cured layer becomes difficult, and the effect of suppressing the exposure of the fibrous base material tends to be lowered. When it is too thick, there is a disadvantage that the thickness of the multilayer printed circuit board is reduced. Further, the thickness can be easily controlled by adjusting the coating amount of the support for the thermosetting resin composition.

The insulating resin sheet of the present invention can be obtained by adhering a cured layer of the thermosetting resin composition to the prepreg. For example, a cured product sheet made of a cured layer of a support and a thermosetting resin composition may be laminated on one side of the prepreg, and the prepreg may be applied to the cured product sheet. The cured layer is laminated and then the method. The cured product sheet and the prepreg may be wound up and continuously laminated on each of the rolls, or the two sheets of the roll may be cut to perform blade type lamination.

In the insulating resin sheet of the present invention, the prepreg layer and the thermosetting resin The total thickness of the cured layer of the composition is generally in the range of 11 μm to 100 μm, preferably in the range of 13 to 70 μm, particularly preferably in the range of 13 to 55 μm. When the thickness of the insulating resin sheet is too small, the insertion of the circuit tends to be insufficient when the insulating layer is formed, and the production tends to be difficult. Moreover, when the thickness of the insulating resin sheet is too thick, the thickness of the multilayer printed wiring board tends to be disadvantageous.

In the insulating resin sheet of the present invention, the surface of the prepreg which is not adhered to the cured layer is preferably protected by a protective film for the purpose of preventing surface depression, prevention of scratches, and prevention of adhesion of foreign matter. The protective film can be the same as the plastic film described in the above description of the support. The thickness of the protective film is generally in the range of 1 to 40 μm, preferably 10 to 30 μm.

The method for producing a multilayer printed wiring board according to the present invention includes the step of laminating the insulating resin sheet of the present invention on one or both sides of the inner layer circuit board, and curing the insulating resin sheet to form an insulating layer, and generally includes the following ( 1)~(3) steps.

(1) The insulating resin sheet is placed on the inner layer circuit board, and the prepreg is bonded to the double-sided or single-sided surface of the inner layer circuit board, and is heated and pressurized via the elastic material under reduced pressure. a lamination step of laminating on a substrate, (2) a smoothing step of heating and pressurizing the laminated insulating resin sheet by a metal plate or a metal roll, and (3) smoothing the insulating resin sheet A thermal hardening step of forming an insulating layer by thermal hardening.

Here, the thickness of the insulating layer is basically included in the total thickness of the cured layer of the thermosetting resin composition and the prepreg. Therefore, the thickness of the insulating layer is generally 11 to 100 μm, preferably 13 to 70 μm, more preferably 13~ 55 μm.

Explain the lamination step. In the inner layer circuit board, the insulating resin sheet is heated and pressurized under reduced pressure, and the insulating resin sheet is laminated on the inner layer circuit board. Under reduced pressure, the air pressure is reduced to an environment of 20 mmHg (26.7 hPa) or less. In the laminating step, heating and pressurization may be performed by pressurizing a metal plate such as a heated SUS mirror plate from the side of the support, but the metal plate is not directly pressurized, and is pressurized with an elastic material such as heat-resistant rubber. The insulating resin sheet on the circuit unevenness of the circuit board can be sufficiently followed. Pressurizing at a preferred temperature of 70 to 140 ° C (more preferably 80 to 130 ° C), preferably a pressure of 1 to 11 kgf / cm ² (9.8 × 10 ⁴ ~ 107.9 × 10 ⁴ N / m ² ) get on.

After the laminating step, smoothing of the laminated insulating resin sheet is performed. This smoothing step is generally carried out under normal pressure (at atmospheric pressure) by heating and pressurizing the insulating resin sheet by a metal plate or a metal roll such as a heated SUS mirror plate. The smoothing is preferably performed by a metal plate. The heating and pressurizing conditions can be the same as those of the above lamination step.

The laminating step and the smoothing step in the present invention can be carried out in a continuous manner by a vacuum laminator being sold. Examples of the vacuum laminating machine to be sold include a vacuum press laminator manufactured by Nippon Machine Co., Ltd., and a vacuum applicator made of Nichigo-morton.

The thermal hardening step is performed after the lamination step or the smoothing step. In the thermal hardening step, the insulating resin sheet is thermally cured to form an insulating layer. In the heat hardening step, the prepreg layer is mainly thermally hardened. The thermosetting conditions vary depending on the type of the thermosetting resin composition, etc., but the general curing temperature is 150. ~200 ° C, hardening time is 15 to 60 minutes.

In the method for producing a multilayer printed wiring board according to the present invention, the step of punching the hole in the insulating layer and the step of roughening the step of roughening the insulating layer may be further included. These steps are well known to those skilled in the art and can be carried out in accordance with various methods used in the manufacture of multilayer printed circuit boards. In the method for producing a multilayer printed wiring board of the present invention, the step of peeling off the support from the thermally cured insulating resin sheet may be further included. The peeling of the support may preferably be carried out after the heat hardening step or after the hole punching step. The peeling of the support can be performed by manual peeling or mechanical peeling by an automatic peeling device. When a metal foil is used as a support, it can remove by etching by an etching solution.

The hole punching step can be performed, for example, by forming a hole such as a via hole or a through hole by a laser such as a cobalt head, a carbon dioxide laser, a YAG laser or the like in the insulating layer. For multilayer printed circuit boards, the formation of the vias is generally performed on the core substrate, and the structured insulating layer is typically turned on by the via holes. Moreover, the formation of perforations generally uses a mechanical cobalt head.

The roughening step can be carried out, for example, by treating the surface of the insulating layer with an oxidizing agent such as an aqueous alkaline permanganic acid solution. The roughening step sometimes has a drilling step that combines holes such as passage holes and perforations. Preferably, the aqueous alkaline permanganic acid solution is first swollen by a swelling liquid. Examples of the swelling liquid include Swelling Dip Securiganth P, Swelling Dip Securiganth SBU, and the like manufactured by Atotech Japan Co., Ltd. The swelling treatment is generally carried out at a temperature of 60 to 80 ° C, and the insulating layer is allowed to be carried out in the swelling liquid for 5 to 10 minutes. An alkaline permanganic acid aqueous solution, for example, dissolved in an aqueous solution of sodium hydroxide A solution of potassium permanganate or sodium permanganate. The roughening treatment of the aqueous alkaline permanganic acid solution is generally carried out at 60 to 80 ° C for 10 to 30 minutes. An alkaline permanganic acid aqueous solution is exemplified as a concentrated compressed CP manufactured by Atotech Japan Co., Ltd., a dispensing solution swelling agent P, and the like.

The method for fabricating the multilayer printed circuit board of the present invention may further comprise a plating step of forming a conductor layer by plating on the surface of the further roughened insulating layer, and after the conductor layer is formed, the circuit substrate is annealed by heating ( Aneal) a step of processing, and a circuit forming step of forming a circuit in the conductor layer. These steps are well known to those skilled in the art and can be carried out in accordance with various methods used in the manufacture of multilayer printed circuit boards.

The plating step is performed, for example, on the surface of the insulating layer on which the uneven anchor is formed by the roughening treatment, and the conductor layer is formed by a combination of electroless plating and electrolytic plating. At this time, plating is also formed in the via hole. As the conductor layer, a copper plating layer is preferred. Although a copper plating layer is generally used in combination with electroless copper plating and electrolytic copper plating, it is also possible to form a plating resist which is inversely patterned with a conductor layer, and to form a conductor layer only by electroless copper plating. The thickness of the electroless plating layer is preferably from 0.1 to 3 μm, more preferably from 0.3 to 2 μm. On the other hand, as the thickness of the electrolytic plating layer, the thickness of the electroless plating layer is preferably 3 to 35 μm, and preferably 5 to 20 μm. Also, the via hole can be formed by plating as a magnetic field channel.

The annealing treatment step is performed, for example, after the conductor layer is formed, and the circuit board is heated at 150 to 200 ° C for 20 to 90 minutes. By the calcination treatment, the peeling strength of the conductor layer can be further improved and stabilized.

As a circuit forming step, for example, a subtractive method can be used. Method), semi-additive method (Semiadditive Method), and the like. Preferably, the thin line is formed by a semi-additive method, and a pattern resist is applied to the electroless plating layer to form an electrolytic plating layer having a desired thickness, and then the pattern resist is removed, and the electroless plating layer is removed by rinsing and etching. Circuit.

Further, the "inner layer circuit substrate" of the present invention is a single surface of a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT grease substrate, or a thermosetting polyphenylene ether substrate. A conductor layer having a patterning process (forming a circuit) on both sides is required to form an intermediate layer of an insulating layer and a conductor layer when manufacturing a multilayer printed circuit board. Further, the surface of the conductor layer is subjected to a pre-roughening treatment by a blackening treatment or the like, and it is preferable from the viewpoint of the adhesion to the inner layer circuit board of the insulating layer.

The invention will be more specifically described below by way of examples and comparative examples.

Further, the "parts" described below indicate "parts by mass".

[Example 1] (made of resin varnish)

A polyvinyl butyral resin ("KS-1" manufactured by Sekisui Chemical Co., Ltd.) was dissolved in a solid at 60 ° C in a solvent in which ethanol and toluene were mixed at a ratio of 1:1 (mass ratio). At 15%, a polyvinyl butyral resin solution was obtained. Next, 28 parts of liquid bisphenol A type epoxy resin (epoxy equivalent weight 180, "Epikote 828EL" made by Japan Epoxy Resins Co., Ltd.), and naphthalene type 4-functional epoxy resin (epoxy equivalent 163, Dainippon Ink Chemistry) Industrial (share) "HP4700") 28 parts, in methyl ethyl ketone ( Hereinafter referred to as "MEK". In a mixed solvent of 15 parts and 15 parts of cyclohexanone, the mixture was heated and dissolved while stirring. Here, a mixed naphthol-based curing agent ("SN-485" manufactured by Tohto Kasei Co., Ltd., phenolic hydroxyl equivalent 215) has a solid content of 50% of a MEK solution of 110%, and a curing catalyst (Four Nations Chemical Industry Co., Ltd.) "2E4MZ") 0.1 parts, spherical cerium oxide (average particle diameter 0.5 μm, "SOC2" manufactured by Admatech Co., Ltd.) 70 parts, and 30 parts of the polyvinyl butyral resin solution described above, and rotated at a high speed by a stirrer Disperse evenly to make a resin varnish.

(Manufacture of hardened sheet)

The release-treated surface of the PET film (38 μm) treated with the alkyd-based release agent was uniformly applied to the dried thermosetting resin composition layer by die coating. The thickness was 15 μm, and it was dried at 80 to 120 ° C (average 100 ° C) for 6 to 8 minutes to obtain a succeeding sheet having a minimum melt viscosity of 1300 poise of the thermosetting resin composition layer. On the surface of the succeeding sheet, a polypropylene film having a thickness of 15 μm as a protective film was bonded and wound up on a roll. Thereafter, the succeeding sheet of the roll was slit into a width of 502 mm to obtain 50 rolls of the succeeding sheet. The protective film of the sheet was peeled off, and each was cured at 150 ° C for 15 minutes, at 160 ° C for 15 minutes, at 170 ° C for 15 minutes, and at 180 ° C for 15 minutes, to obtain a thermosetting resin composition. The glass transition temperatures of the cured materials were each 86 ° C, 99 ° C, 113 ° C, and 129 ° C hardened flakes. On the other hand, in the same manner, a sheet of a roll of a thermosetting resin composition layer having a thickness of 10 μm and 5 μm was obtained, and after peeling off the protective film, it was thermally cured at 180 ° C for 15 minutes to obtain a hardening of the thermosetting resin composition. The glass transition temperature of the object was two kinds of hardened flakes at 129 °C.

(manufacturing of prepreg)

The resin varnish was impregnated into a 1015 NS glass cloth (thickness: 16 μm) manufactured by Azawa Seisakusho Co., Ltd., and dried to a residual solvent amount of 0.6% to obtain a prepreg having a thickness of 35 μm. Next, a polypropylene film having a thickness of 15 μm was laminated on one side of the prepreg, and a PET film of 38 μm was laminated on the other side.

(Manufacture of insulating resin sheet)

The prepreg of the cured polypropylene sheet having a glass transition temperature of 86 ° C in a cured product of the thermosetting resin composition is placed on the cured surface of the cured sheet, and the vacuum prepreg is produced by using a polypropylene film. The laminator was subjected to vacuum suction at a temperature of 120 ° C for 30 seconds, and then laminated on a PET film with a heat-resistant rubber for 30 seconds under the conditions of a temperature of 120 ° C and a pressure of 7.0 kg / cm ² . Next, under pressure at atmospheric pressure, a SUS mirror plate was used, and the mixture was pressed at a temperature of 120 ° C under a pressure of 5 kg/cm ² for 60 seconds to obtain an insulating resin sheet.

(Lamination of insulating resin sheets)

The obtained insulating resin sheet was laminated on both sides of an inner layer circuit board (IPC MULTI-PURPOSE TESTBOARD No. IPC-B-25, conductor thickness 18 μm, 0.8 mm thick). This laminate was used in a vacuum press laminator MVLP-500 manufactured by Seiki Co., Ltd., and vacuum-sucked at a temperature of 80 ° C for 30 seconds, and then at a temperature of 80 ° C and a pressure of 7.0 kg / cm ² . The heat-resistant rubber was laminated on the PET film by applying pressure for 60 seconds. Next, a SUS mirror plate was used under atmospheric pressure, and pressurization was carried out for 90 seconds under the conditions of a temperature of 80 ° C and a pressure of 5.5 kg / cm ² .

(hardening of resin composition)

The PET film was peeled off from the laminated insulating resin sheet, and the thermosetting resin composition (prepreg) was cured at 180 ° C for 30 minutes using a hot air circulating furnace to form an insulating layer. Thereby, a laminate in which an insulating layer is formed on both surfaces of the inner layer circuit board is obtained.

(roughening treatment)

The resulting laminate was subjected to a roughening treatment by permanganic acid solution. First, as a swelling treatment, Swelling Dip Securiganth P manufactured by Atotech Japan Co., Ltd., impregnated for 5 minutes at 60 ° C, followed by oxidation treatment, and concentrated in Atotech Japan. Compress CP and dispense solution. The mixture of the swelling agent P was impregnated at 80 ° C for 20 minutes, and then subjected to reduction treatment in a reduction solution Securiganth P500 solution manufactured by Atotech Japan Co., Ltd. for 5 minutes at 40 ° C for 5 minutes.

(by the formation of a conductive layer of plating)

On the surface of the insulating layer of the obtained laminate, Activator Neoganth 834 manufactured by Atotech Japan Co., Ltd. containing palladium was used, and after the catalyst supply of electroless copper plating, the printganth MSK-DK made of Atotech Japan containing tartrate was used. Perform electroless plating. Next, electrolytic plating was performed using copper sulfate to a copper thickness of about 20 μm. Thereafter, it was hardened at 180 ° C for 30 minutes to obtain a multilayer printed circuit board.

[Embodiment 2]

A multilayer printed wiring board was obtained in the same manner as in Example 1 except that a cured product sheet having a glass transition temperature of 99 ° C (the thickness of the thermosetting resin composition layer (hardened layer) was 15 μm) was used as the cured product sheet. .

[Example 3]

A multilayer printed wiring board was obtained in the same manner as in Example 1 except that the cured product sheet having a cured product having a glass transition temperature of 113 ° C (the thickness of the thermosetting resin composition layer (cured layer) was 15 μm) was used. .

[Example 4]

A multilayer printed wiring board was obtained in the same manner as in Example 1 except that the temperature of the step of laminating and smoothing the insulating resin sheet to the inner layer circuit board was set to 100 °C.

[Example 5]

As the cured product sheet, a cured sheet having a glass transition temperature of 99 ° C (the thickness of the thermosetting resin composition layer (cured layer) is 15 μm), and the lamination of the insulating resin sheet to the inner layer circuit board is used. A multilayer printed wiring board was obtained in the same manner as in Example 1 except that the temperature of the smoothing step was 100 °C.

[Embodiment 6]

As the cured product sheet, a cured product sheet having a glass transition temperature of 113 ° C (the thickness of the thermosetting resin composition layer (cured layer) is 15 μm), and the lamination of the insulating resin sheet to the inner layer circuit board is used. A multilayer printed wiring board was obtained in the same manner as in Example 1 except that the temperature of the smoothing step was 100 °C.

[Embodiment 7]

A multilayer printed wiring board was obtained in the same manner as in Example 1 except that the temperature of the step of laminating and smoothing the insulating resin sheet to the inner layer circuit board was 120 °C.

[Embodiment 8]

As the cured product sheet, a cured product sheet having a glass transition temperature of 99 ° C (the thickness of the thermosetting resin composition layer (cured layer) is 15 μm), and the lamination of the insulating resin sheet to the inner layer circuit board is used. A multilayer printed wiring board was obtained in the same manner as in Example 1 except that the temperature of the smoothing step was 120 °C.

[Embodiment 9]

As the cured product sheet, a cured sheet having a glass transition temperature of 113 ° C (the thickness of the thermosetting resin composition layer (hardened layer) is 15 μm) is used, and the insulating resin sheet is laminated to the inner layer circuit board. A multilayer printed wiring board was obtained in the same manner as in Example 1 except that the temperature of the smoothing step was 120 °C.

[Embodiment 10]

As the cured product sheet, a cured product sheet having a glass transition temperature of 129 ° C (the thickness of the thermosetting resin composition layer (hardened layer) is 15 μm), and the lamination of the insulating resin sheet to the inner layer circuit board is used. A multilayer printed wiring board was obtained in the same manner as in Example 1 except that the temperature of the smoothing step was 100 °C.

[Example 11]

As the cured product sheet, a cured product sheet having a glass transition temperature of 129 ° C (the thickness of the thermosetting resin composition layer (cured layer) is 10 μm), and the lamination of the insulating resin sheet to the inner layer circuit board is used. A multilayer printed wiring board was obtained in the same manner as in Example 1 except that the temperature of the smoothing step was 100 °C.

[Embodiment 12]

As the cured product sheet, a cured product sheet having a glass transition temperature of 129 ° C (the thickness of the thermosetting resin composition layer (cured layer) is 5 μm), and the lamination of the insulating resin sheet to the inner layer circuit board is used. A multilayer printed wiring board was obtained in the same manner as in Example 1 except that the temperature of the smoothing step was 100 °C.

[Example 13]

As the cured product sheet, a cured product sheet having a glass transition temperature of 129 ° C (the thickness of the thermosetting resin composition layer (hardened layer) is 15 μm), and the lamination of the insulating resin sheet to the inner layer circuit board is used. A multilayer printed wiring board was obtained in the same manner as in Example 1 except that the temperature of the smoothing step was 120 °C.

[Embodiment 14]

As the cured product sheet, a cured product sheet having a glass transition temperature of 129 ° C (the thickness of the thermosetting resin composition layer (cured layer) is 10 μm), and the lamination of the insulating resin sheet to the inner layer circuit board is used. A multilayer printed wiring board was obtained in the same manner as in Example 1 except that the temperature of the smoothing step was 120 °C.

[Example 15]

As the cured product sheet, a cured product sheet having a glass transition temperature of 129 ° C (the thickness of the thermosetting resin composition layer (cured layer) is 5 μm), and the lamination of the insulating resin sheet to the inner layer circuit board is used. A multilayer printed wiring board was obtained in the same manner as in Example 1 except that the temperature of the smoothing step was 120 °C.

<Comparative Example 1>

A multilayer printed wiring board was obtained in the same manner as in Example 1 except that a prepreg layer having a thickness of 50 μm was used instead of the insulating resin sheet. The prepreg having a thickness of 50 μm was obtained by impregnating a resin varnish similar to that of Example 1 into a 1015 NS glass cloth (thickness: 16 μm) manufactured by Tosawa Manufacturing Co., Ltd. to a thickness of 50 μm of the obtained prepreg, and 80 to 150. It was obtained by drying at ° C for 10 minutes.

<Comparative Example 2>

A multilayer printed wiring board was obtained in the same manner as in Example 1 except that the succeeding sheet (the succeeding sheet used in the production of the cured sheet in Example 1) was used instead of the cured sheet.

The evaluation of the cured sheet, the prepreg, the insulating resin sheet, and the multilayer printed board obtained in the above Examples and Comparative Examples was carried out as follows. The results are shown in Table 1 below.

(evaluation of liquidity)

Using a vacuum press laminator manufactured by Seiki Co., Ltd., the cured sheet was cut into a rectangular shape having a plane size of 12 cm × 15 cm, and placed on a 20 cm square 0.8 mm thick FR4 substrate and placed in a concentric shape. The form was laminated and smoothed under the same conditions as in the respective examples and comparative examples, and the fluidity was evaluated by the scale of the scale. After laminating at a temperature of 80 ° C for 30 seconds, vacuum suction was carried out, and at a temperature of 80 ° C and a pressure of 7.0 kg/cm ² , the heat-resistant rubber was laminated on the PET film by pressurization for 60 seconds, and smoothed to Under a pressure of atmospheric pressure, pressurization was carried out for 90 seconds under the conditions of a temperature of 80 ° C and a pressure of 5.5 kg/cm ² using a SUS mirror plate. The maximum scale of the resin present from the four sides after pressurization was measured.

The length of the scale is the length in the vertical direction of the end portion (end side) of the resin exposed from the end portion (end side) of the PET film, and can be measured by a CCD type microscope (manufactured by Keyence, VH6300). The measurement was carried out.

(Measurement of glass transition temperature)

For the cured sheet obtained in the examples and the comparative examples, a small piece of the cured layer of the thermosetting resin composition was used as a sample, and a type DMS-6100 manufactured by Seiko Instruments Co., Ltd. was used as a thermomechanical analyzer (DMA). The measurement was carried out in "stretch mode". The measurement was carried out at a temperature of 2 ° C / min, and in the range of 25 ° C to 240 ° C. The value obtained by rounding off the first decimal point of the maximum value of the loss positive tangent (tan δ) obtained by the ratio of the measured elastic modulus (E') to the loss elastic modulus (E") is taken as the glass transition temperature. When it is not hardened, it cannot be measured.

(Measurement of the lowest melt viscosity)

The type of Rheosol-G3000 manufactured by UBM was used, and the amount of the resin was taken as 1 g. Further, a parallel plate having a diameter of 18 mm was used to measure the starting temperature at 60 ° C, the temperature increase rate at 5 ° C / min, and the number of vibrations at 1 HZ / deg. The lowest viscosity value (η) was taken as the lowest melt viscosity.

The thermosetting resin composition of the prepreg layer used in the examples and the comparative examples had a minimum melt viscosity of about 1500 poise. Further, the cured layer of the Example had a melt viscosity of 500,000 poise or more and could not be measured. The thermosetting resin composition layer of Comparative Example 2 had a minimum melt viscosity of about 1600 poise.

(Measurement of thickness of insulating resin sheet, cured sheet layer, and prepreg)

The measurement was carried out using a contact type film thickness meter (manufactured by Mitutoyo, M CD-25MJ).

(Exposure of glass cloth and residual copper plating)

The plating film on the P coupon of the inner layer circuit board was peeled off, and the presence or absence of the glass cloth was observed using a CCD type microscope (VH6300, manufactured by Keyence Corporation). Further, in the case where the glass cloth is exposed, the copper plating is immersed in the copper plating, and the copper plating remains after the plating film is peeled off.

[assessment]

○: The surface of the resin of the glass cloth on the P test piece was not exposed, and no plating copper remained.

X: The glass cloth was exposed on the surface of the resin of the P test piece, or plating copper remained at this position.

(insertion to the circuit)

The laminate of the cross section of the step portion of the P test piece in the cut circuit board was observed by a scanning electron microscope (SEM) to confirm whether or not resin was embedded between the circuits.

[assessment]

○: There is resin in between the circuits.

×: There is a residual space between the circuits, which is not completely embedded.

As shown in the results shown in Table 1, the insulating resin sheets formed of the prepregs and the cured layer of Examples 1 to 15 were laminated and hardened on the inner layer circuit substrate, and even after the roughening treatment, the glass cloth was applied. Not exposed on the surface of the resin, and no copper plating remains. On the other hand, in Comparative Example 1 in which a prepreg was used alone and Comparative Example 2 in which an insulating resin sheet made of a prepreg and a thermosetting resin composition layer (unhardened) was used, it was observed by roughening. The exposed glass cloth is exposed.

[Industrial availability]

The present invention relates to a method for producing an insulating resin sheet useful for forming an insulating layer of a multilayer printed circuit board, using the insulating resin sheet obtained by the manufacturing method, and the fiber of the prepreg even after roughening the surface of the insulating layer The substrate is not exposed, and a highly reliable multilayer printed circuit board can be manufactured. Therefore, the obtained multilayer printed wiring board can be used, for example, as a high-density small-sized printed circuit board carrying a semiconductor wafer, and can also be expected to be a thin or simplistic small-sized, lightweight novel semiconductor component as a core substrate. Material use.

This application is based on Japanese Patent Application No. 2008-078624, the entire contents of which are incorporated herein by reference.

Claims (12)

An insulating resin sheet characterized by having a cured layer of a thermosetting resin composition on one surface of a prepreg, further having a support layer on the cured layer, and a side of the hardened layer of the support layer being subjected to mold release treatment . An insulating resin sheet according to claim 1, wherein the cured product sheet of the cured layer of the thermosetting resin composition is formed on the support body and then obtained on one side of the prepreg. An insulating resin sheet according to claim 1 or 2, wherein the support layer is a plastic film. An insulating resin sheet according to claim 1 or 2, wherein the prepreg surface of the insulating resin sheet is protected by a protective film. For example, the insulating resin sheet of claim 1 or 2, wherein the prepreg has a thickness of 10 to 70 μm. The insulating resin sheet according to claim 1 or 2, wherein the cured layer of the thermosetting resin composition is 1 to 30 μm. An insulating resin sheet according to claim 1 or 2, wherein the insulating resin sheet is used to (1) the insulating resin sheet is disposed under the inner layer circuit substrate to be bonded to the double-sided or single-sided surface of the inner layer circuit substrate, a lamination step of laminating on an inner layer circuit substrate by heating and pressurizing by an elastic material under reduced pressure, and (2) heating the laminated insulating resin sheet by a metal plate or a metal roll A step of smoothing the smoothing of the insulating resin sheet and (3) a method of producing a multilayer printed wiring board in which the smoothed insulating resin sheet is thermally cured. Such as the insulating resin sheet in the seventh application patent range, wherein the heat The cured layer of the curable resin composition does not substantially have fluidity in the laminating step and the smoothing step. A multilayer printed circuit board characterized by forming an insulating layer by an insulating resin sheet according to any one of claims 1 to 8. A method of manufacturing a multilayer printed circuit board, comprising: (1) placing an insulating resin sheet according to any one of claims 1 to 8 under an inner layer circuit substrate to bond the prepreg layer to The double-sided or single-sided surface of the inner circuit board, the lamination step of laminating on the inner layer circuit substrate by heating and pressurizing by the elastic material under reduced pressure, and (2) laminating the insulating resin A smoothing step of heating and pressurizing the sheet by a metal plate or a metal roll, and (3) a heat hardening step of thermally curing the smoothed insulating resin sheet. The method of claim 10, wherein the heating and pressing of the insulating resin sheet in the laminating step and the smoothing step are performed on the support layer. The method of claim 10, wherein the method further comprises the step of punching holes in the insulating layer, the roughening step of roughening the insulating layer, and borrowing on the surface of the roughened insulating layer. A plating step of forming a conductor layer by plating, and a circuit forming step of forming a circuit in the conductor layer.