JP2007318071A - Insulating base board, base board with metal foil, and printed circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulating base board, a base board with a metal foil, and a printed circuit board whose hygroscopicity is low, whose dimension stability is excellent, and whose bending performance and dust resistivity is satisfactory. <P>SOLUTION: This insulating base board 20 is configured of a fiber base and a resin composition, and sets the maximum thickness of the fiber base as 30 μm or less, and sets the content of the fiber base as 17 mass% or less as a whole. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an insulating substrate, a substrate with a metal foil, and a printed wiring board.

  A printed wiring board is, for example, a subtractive method on a substrate with a metal foil in which a predetermined number of prepregs and metal foils or prepregs and resin-added metal foils that are made of an electrically insulating resin composition as a matrix are laminated by heating and pressing. Can be obtained by forming a printed circuit.

  The substrate with metal foil is generally manufactured by stacking a metal foil such as a copper foil on the surface of the prepreg, or by heating and pressing the prepreg and the metal foil with resin.

  For example, a multilayer printed wiring board having a plurality of circuit layers is formed by laminating a second circuit forming resin and a metal foil on the inner layer circuit and applying interlayer connection, or processing an insulating resin layer. After forming, it can be obtained by forming an upper circuit layer by electroless plating and electroplating.

  As a method for laminating the second circuit forming resin and the metal foil, a method of simultaneously laminating and pressing a prepreg and a copper foil, or an electrically insulating resin composition having adhesiveness on the metal foil in advance. There is a method of laminating a so-called metal foil with a resin on a layer containing a fiber base material.

  Thermoelectric resins such as phenolic resins, epoxy resins, polyimide resins, and bismaleimide-triazine resins are widely used as electrical insulating resins, and thermoplastic resins such as fluororesins and polyphenylene ether resins are also used. It is used according to.

  Printed wiring boards manufactured by the above-described technology have been reduced in size and increased in density with the spread of information terminal devices such as personal computers and mobile phones. The mounting form has progressed from a pin insertion type to a surface mounting type, and further to an area array type typified by BGA (ball grid array) using a plastic substrate.

  In a substrate on which a bare chip such as a BGA is directly mounted, the connection between the chip and the substrate is generally performed by wire bonding using thermosonic bonding. In this case, since the printed wiring board on which the bare chip is mounted is exposed to a high temperature of 150 ° C. or higher, it is necessary to have heat resistance.

  In some cases, the printed wiring board is required to have a so-called repair property in which a chip once mounted is removed. When removing the chip, the same level of heat as that applied during chip mounting is applied, and then further heat treatment is applied when chip mounting is performed again. For this reason, printed wiring boards that require repairability must also have cyclic thermal shock resistance at high temperatures.

  However, the conventional printed wiring board has insufficient heat resistance and thermal shock resistance, and has a problem of causing separation between the fiber base material and the resin. Therefore, in order to improve heat resistance, thermal shock resistance, reflow resistance, crack resistance, and improve fine wiring formability, a laminated board in which a fiber base material is impregnated with a resin composition containing polyamideimide as an essential component, (Refer patent document 1) The heat resistant laminated board which impregnated the fiber base material with the resin composition which consists of a silicone modified polyimide resin and a thermosetting resin is proposed (refer patent document 2).

  On the other hand, with recent downsizing and higher performance of electronic equipment, it has excellent heat resistance and thermal shock resistance and can be stored in a limited space, that is, the space in the housing can be bent arbitrarily. There is a need for a printed wiring board that can be used effectively.

In order to meet such demands, a plurality of printed wiring boards are arranged in multiple stages and connected to each other by a wire harness or a flexible wiring board, or a rigid-flex which is a multilayer of a polyimide-based flexible board and a conventional rigid board. A substrate is used.
JP 2003-55486 A JP-A-8-193139

  However, a flexible wiring board made of a resin that does not have a fiber substrate does not have sufficient dimensional stability, such as a large dimensional change during moisture absorption. In addition, in the rigid-flex substrate, the manufacturing process becomes complicated and it is difficult to achieve further thinning.

  On the other hand, since the conventional printed wiring board containing a fiber base material does not have sufficient flexibility, it is required to have characteristics such as so-called bendability that can be arbitrarily bent.

  Furthermore, since the conventional printed wiring board containing a fiber base material generates resin powder during processing such as cutting and punching, it suppresses the generation of resin powder during processing, so-called dust resistance. There is a need for improvement.

  Therefore, an object of the present invention is to provide an insulating substrate, a substrate with metal foil, and a printed wiring board that have low hygroscopicity, excellent dimensional stability, and have both good bendability and dust generation resistance. .

  In order to achieve the above object, the insulating substrate of the present invention is an insulating substrate composed of a fiber base material and a resin composition, the maximum thickness of the fiber base material is 30 μm or less, and the content of the fiber base material is It is characterized by being 17% by mass or less of the whole.

  According to the present invention, the maximum thickness of the fiber base material of the insulating substrate is 30 μm or less, and the fiber base material content is 17% by mass or less of the entire insulating substrate, thereby reducing the thickness of the fiber base material. At the same time, the ratio of the flexible resin composition is increased, and it is possible to bend it into an arbitrary state at an arbitrary portion. In addition, by including a resin composition having low elasticity and excellent flexibility, generation of resin powder can be suppressed even during processing such as cutting and punching. As a result, it is possible to obtain a printed wiring board having both good bendability and good dust resistance, an insulating substrate capable of forming such a printed wiring board, and a substrate with metal foil.

  In the insulating substrate of the present invention, the ratio of the maximum thickness of the fiber base material to the entire thickness is preferably 0.05 to 0.20.

  As a result, the insulating substrate contains the fiber base material and the flexible resin composition in a certain range, and an insulating substrate having both excellent bending resistance and dimensional stability can be obtained. .

  In the insulating substrate of the present invention, the resin composition is a cured product of a thermosetting resin composition, the tensile elastic modulus of the resin composition is 0.5 to 10 GPa at 20 to 30 ° C., and the glass transition point or less. The coefficient of thermal expansion at temperature is preferably 100 to 400 ppm.

  By providing a resin having such properties, a resin composition having excellent heat resistance and dimensional stability can be obtained.

  The thermosetting resin composition preferably includes a polymer having an amide group and a weight average molecular weight of 20,000 to 50,000.

  Thereby, the resin layer excellent in flexibility can be constructed, and an insulating substrate with good workability can be obtained. Moreover, the impregnation property to the fiber base material of a thermosetting resin composition can be improved by adjusting a weight average molecular weight to the said range.

  The thermosetting resin composition preferably includes one or both of an epoxy resin and an acrylic resin.

  By including an epoxy resin, heat resistance and insulation can be improved. Moreover, the resin composition which is further excellent in a softness | flexibility can be obtained by including an acrylic resin, and the bendability of an insulating board | substrate can be improved. By including both an epoxy resin and an acrylic resin, it is possible to obtain a resin composition that is more excellent in flexibility and excellent in moisture resistance, and an insulating substrate that is excellent in these characteristics can be obtained.

  The board | substrate with metal foil of this invention is equipped with the above-mentioned insulating board | substrate and the metal foil provided on the main surface of the insulating board | substrate. Moreover, the printed wiring board of this invention can be obtained from the above-mentioned insulating board | substrate or a board | substrate with metal foil. Therefore, the board | substrate with metal foil and a printed wiring board which have the above-mentioned characteristic can be obtained.

  According to the present invention, it is possible to provide an insulating substrate, a substrate with metal foil, and a printed wiring board that have low hygroscopicity and excellent dimensional stability, and have both good bendability and dust generation resistance. Since such a printed wiring board can bend | fold a required part arbitrarily, the space in a housing | casing can be used effectively and it can accommodate in the housing | casing mounted in high density.

  Hereinafter, preferred embodiments of an insulating substrate, a substrate with metal foil, and a printed wiring board according to the present invention will be described with reference to the drawings as necessary.

  FIG. 1 is a partial cross-sectional view of a substrate with metal foil and an insulating substrate according to an embodiment of the present invention. A substrate 100 with a metal foil includes an insulating substrate 20 including a fiber base reinforcing layer 3 and a resin layer 5 stacked on both sides of the fiber base reinforcing layer 3, and a metal foil stacked on both sides of the insulating substrate 20. 10.

  The thickness in the stacking direction of the insulating substrate 20 including the fiber base material reinforcing layer 3 and the resin layer 5 is preferably 60 to 200 μm from the viewpoint of obtaining even better bendability.

  The fiber base material reinforcing layer 3 contains a fiber base material and a resin composition impregnated therein. The fiber substrate reinforcing layer 3 can be formed by impregnating a fiber substrate with a thermosetting resin composition and curing the thermosetting resin composition.

  The maximum thickness of the fiber base material in the direction perpendicular to the main surface of the insulating substrate is 30 μm or less from the viewpoint of ensuring bendability. Further, from the viewpoint of strength against breakage and twist of the insulating substrate, the maximum thickness of the fiber base material in the direction perpendicular to the main surface of the insulating substrate is preferably 8 μm or more.

  As the fiber substrate contained in the fiber substrate reinforcing layer 3, woven fabric, non-woven fabric or the like can be used, and the material thereof is glass, alumina, asbestos, boron, silica alumina glass, silica glass, tyranno, carbonized. Inorganic fibers such as silicon, silicon nitride, and zirconia, organic fibers such as aramid, polyetheretherketone, polyetherimide, polyethersulfone, carbon, and cellulose, and mixed papers thereof can be used. Among these, from the viewpoint of obtaining excellent dimensional stability, heat resistance, and bendability, a glass fiber woven fabric, that is, a glass cloth is preferable.

  For example, as a commercially available glass cloth, WEX1015, WEX1027, and 1037 (the above, the product name made by Nittobo Co., Ltd.) can be used suitably.

  As a raw material of the fiber base material of the fiber base material reinforcing layer 3, for example, by using a glass cloth having a thickness of 50 μm or less, the maximum fiber base material in the direction perpendicular to the main surface of the insulating substrate after the insulating substrate is formed. The thickness can be 30 μm or less. As a result, it is possible to obtain an insulating substrate, a substrate with a metal foil, and a printed wiring board that can be bent arbitrarily and have small dimensional changes due to heating, moisture absorption, and the like during manufacturing.

  The resin layer 5 has the same resin composition as the resin composition contained in the fiber base material reinforcing layer 3 from the viewpoint of improving the heat resistance of the insulating substrate by making the adhesive strength with the fiber base material reinforcing layer 3 stronger. It is preferable that it is a thing.

  The maximum thickness of the resin layer 5 in the direction perpendicular to the main surface of the insulating substrate is preferably 5 to 60 μm. When the maximum thickness is less than 5 μm, the bendability of the resin layer 5 tends to decrease, and when the maximum thickness exceeds 60 μm, the dimensional stability during moisture absorption tends to decrease.

  The tensile elastic modulus at 20 to 30 ° C. of the resin composition of the resin layer 5 is preferably 0.5 to 10 GPa, more preferably 0.5 to 8 GPa, and further preferably 1 to 5 GPa. . When the tensile elastic modulus exceeds 10 GPa at 20 to 30 ° C., the thermal shock resistance is low, and the bending property, that is, the flexibility tends to decrease. On the other hand, when the tensile elastic modulus is less than 0.5 GPa at 20 to 30 ° C., the insulating substrate tends to be deformed and the strength tends to decrease.

  The tensile modulus is obtained, for example, by measuring the stress-strain curve of a test substrate of an insulating substrate with a tensile tester under the conditions of a pulling speed of 5 mm / min and room temperature (25 ° C.) and determining the initial inclination of the measurement. Can do.

  The thermal expansion coefficient of the resin composition of the resin layer 5 is preferably less than 400 ppm and more preferably 100 to 400 ppm in the temperature range below the glass transition point. If the thermal expansion coefficient exceeds 400 ppm in the temperature range below the glass transition point, the dimensional change in the direction perpendicular to the main surface of the insulating substrate accompanying the temperature change, that is, the thickness direction of the insulating substrate increases, so that the thermal shock resistance Tends to decrease. Moreover, it is substantially difficult to produce a resin composition having a thermal linear expansion coefficient of less than 100 ppm in a temperature range below the glass transition point.

  As the metal foil 10, a copper foil or an aluminum foil can be generally used. Of these, copper foil is preferred because it is a common conductor material for printed wiring boards. As the metal foil, one having a thickness of 0.5 to 40 μm, preferably 3 to 20 μm, which is used for a normal substrate with metal foil can be used.

  As the metal foil 10, an intermediate layer of nickel, nickel-phosphorus, nickel-tin alloy, nickel-iron alloy, lead, lead-tin alloy, etc., with a copper layer of 0.5-15 μm and a copper layer of 10-40 μm A three-layer composite foil or a two-layer composite foil in which aluminum and copper foil are combined can also be used.

  In the production of the substrate 100 with a metal foil, if a metal foil with a resin in which a thermosetting resin composition and a metal foil are laminated, the thermosetting resin composition and the metal foil 10 that form the resin layer 5 are obtained. They can be stacked together. Use of the metal foil with resin is preferable from the viewpoint of simplifying the production of the substrate with metal foil.

  The ratio of the maximum thickness of the fiber base material to the total thickness of the insulating substrate 20 in the stacking direction of the substrate 100 with metal foil is preferably 0.05 to 0.20, and is 0.07 to 0.17. Is more preferable, and 0.09 to 0.15 is even more preferable. By setting the ratio in the range of 0.07 to 0.17, it is possible to obtain a substrate with metal foil, an insulating substrate, and a printed wiring board that are more excellent in bendability, dust generation resistance, and dimensional stability. . By setting the ratio in the range of 0.09 to 0.15, it is possible to obtain a substrate with metal foil, an insulating substrate, and a printed wiring board that are further excellent in bendability, dust generation resistance, and dimensional stability. it can.

  The resin composition contained in the fiber substrate reinforcing layer 3 and the resin layer 5 is a cured product of a thermosetting resin composition containing a thermosetting resin from the viewpoint of obtaining excellent moldability, heat resistance, and insulation. Preferably there is.

  As the thermosetting resin, epoxy resin, polyimide resin, unsaturated polyester resin, polyurethane resin, bismaleimide resin, triazine-bismaleimide resin, phenol resin, or the like can be used. Among thermosetting resins, it is preferable to include a resin having a glycidyl group, and it is more preferable to include an epoxy resin.

  Examples of the epoxy resin include polyglycidyl ether and phthalate obtained by reacting a polyhydric phenol such as bisphenol A, a novolac type phenol resin, an ortho cresol novolac type phenol resin or a polyhydric alcohol such as 1,4-butanediol with epichlorohydrin. Polyglycidyl ester obtained by reacting polybasic acid such as acid, hexahydrophthalic acid and epichlorohydrin, amine, amide or heterocyclic nitrogen base, N-glycidyl derivative, alicyclic epoxy resin, etc. It is done.

  A thermosetting resin composition can improve thermal, mechanical, and electrical characteristics by including an epoxy resin. In order to form such a resin composition, it is preferable to use, for example, an epoxy resin having two or more glycidyl groups and one or both of a curing agent and a curing accelerator.

  From the viewpoint of improving thermal, mechanical, and electrical characteristics, the more glycidyl groups contained in the epoxy resin, the better, and more preferably three or more. The blending amount of the epoxy resin in the thermosetting resin composition differs depending on the number of glycidyl groups, and the blending amount of the epoxy resin in the thermosetting resin composition can be reduced as the glycidyl group increases.

  The curing agent and curing accelerator for the epoxy resin can be used without limitation as long as they react with the epoxy resin or accelerate the curing. For example, amines, imidazoles, polyfunctional phenols, acid anhydrides and the like can be used.

  As the amines, dicyandiamide, diaminodiphenylmethane, guanylurea and the like can be used. As the polyfunctional phenols, hydroquinone, resorcinol, bisphenol A and their halogen compounds, and a novolak type phenol resin or resole which is a condensate with formaldehyde. Type phenolic resin can be used. As the acid anhydrides, phthalic anhydride, benzophenone tetracarboxylic dianhydride, methyl hymic acid, or the like can be used. As the imidazoles, alkyl group-substituted imidazoles, benzimidazoles and the like can be used.

  When using amines as a hardening | curing agent or a hardening accelerator, it is preferable that the compounding quantity makes the equivalent of the active hydrogen of an amine, and the epoxy equivalent of an epoxy resin substantially equal. When imidazoles are used as a curing agent or a curing accelerator, the blending amount is not simply an equivalent ratio with active hydrogen, and is preferably 0.001 to 10 parts by mass with respect to 100 parts by mass of the epoxy resin. .

  When polyfunctional phenols and acid anhydrides are used as the curing agent or curing accelerator, the blending amount is 0.6 to 1.2 equivalents of phenolic hydroxyl group or carbonyl group with respect to 1 equivalent of epoxy resin. Is preferred.

  If the blending amount of the curing agent and the curing accelerator is small, uncured epoxy resin remains and Tg (glass transition temperature) tends to be low. If it is excessive, unreacted curing agent and curing accelerator remain. Insulation tends to decrease.

  The thermosetting resin composition can contain a high molecular weight resin component for the purpose of improving flexibility and heat resistance.

  The high molecular weight resin component preferably includes a resin having an amide group or an acrylic resin.

  As the high molecular weight resin component, for example, an acrylic acid monomer, a methacrylic acid monomer, acrylonitrile, a polymer obtained by polymerizing an acrylic monomer having a glycidyl group alone, or a copolymer obtained by copolymerizing a plurality of these is used. it can. The molecular weight of the acrylic resin is not particularly specified, but is preferably 300,000 to 1,000,000, and more preferably 400,000 to 800,000 in terms of standard polystyrene equivalent weight average molecular weight.

  It is preferable to add an epoxy resin, a curing agent, a curing accelerator, or the like to these acrylic resins as appropriate. As acrylic resins, HTR-860-P3 (manufactured by Nagase ChemteX Corporation, trade name, weight average molecular weight 850,000), HM6-1M50 (manufactured by Nagase ChemteX Corporation, trade name, weight average molecular weight 500,000), etc. Can be illustrated.

  Examples of the resin having an amide group include a polyamideimide resin, a polyamide resin, and an amide epoxy resin, and a polyamideimide resin is preferable.

  As the polyamideimide resin, a siloxane-modified polyamideimide resin having a siloxane structure in the resin is preferable. In particular, a resin obtained by reacting a mixture containing diimide dicarboxylic acid obtained by reacting a mixture of diamine and siloxane diamine having two or more aromatic rings with trimellitic anhydride and diisocyanate is preferable.

  In the synthesis of a siloxane-modified polyamideimide resin having a siloxane structure in the resin, the mixing ratio of the diamine (b) having two or more aromatic rings and the siloxane diamine (d) is b / d = 99.9 / 0. 0.1 to 0.1 / 99.9 (molar ratio), more preferably b / d = 97/3 to 50/50, and b / d = 95/5 to 80/20. More preferably it is. When the mixing ratio decreases, the Tg of the resin composition tends to decrease, and when the mixing ratio increases, the amount of varnish solvent remaining in the resin tends to increase when a film is produced.

  Examples of the aromatic diamine (diamine having an aromatic ring) used in the production of the polyamideimide resin include 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) and bis [4- (3 -Aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, bis [4- (4-amino Phenoxy) phenyl] methane, 4,4′-bis (4-aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ketone, 1, 3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2′-di Tilbiphenyl-4,4′-diamine, 2,2′-bis (trifluoromethyl) biphenyl-4,4′-diamine, 2,6,2 ′, 6′-tetramethylbiphenyl-4,4′-diamine 5,5′-dimethyl-2,2′-sulfonyl-biphenyl-4,4′-diamine, 3,3′-dihydroxybiphenyl-4,4′-diamine, (4,4′-diamino) diphenyl ether, ( 4,4′-diamino) diphenylsulfone, (4,4′-diamino) benzophenone, (3,3′-diamino) benzophenone, (4,4′-diamino) diphenylmethane, (4,4′-diamino) diphenyl ether, Examples include (3,3′-diamino) diphenyl ether.

  Examples of the siloxane diamine used for the production of the polyamide-imide resin include the following general formulas (1) to (4). In the following general formulas (1) to (4), m and n are integers of 1 or more.

  In addition, as siloxane diamine represented by the said General formula (1), X-22-161AS (made by Shin-Etsu Chemical Co., Ltd., brand name, amine equivalent 450), X-22-161A (made by Shin-Etsu Chemical Co., Ltd.) , Trade name, amine equivalent 840), X-22-161B (manufactured by Shin-Etsu Chemical Co., Ltd., trade name, amine equivalent 1500), BY16-853 (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name, amine equivalent 650), BY16-853B (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name, amine equivalent 2200) can be exemplified.

  As siloxane diamine represented by the general formula (4), X-22-9409 (manufactured by Shin-Etsu Chemical Co., Ltd., trade name, amine equivalent 700), X-22-1660B-3 (manufactured by Shin-Etsu Chemical Co., Ltd.) , Trade name, amine equivalent 2200) and the like.

  For the synthesis of a siloxane-modified polyamideimide resin having a siloxane structure in a resin or a polyamic acid containing a siloxane structure, an aliphatic diamine represented by the following general formula (5) may be used alone, You may use together with a group diamine.

［但し、式（５）中、Ｘはメチレン基、スルホニル基、エーテル基、カルボニル基又は単結合を示し、Ｒ^１及びＲ^２はそれぞれ独立に水素原子、アルキル基、フェニル基又は置換フェニル基を示し、ｐは１〜５０の整数を示す。］

[In the formula (5), X represents a methylene group, a sulfonyl group, an ether group, a carbonyl group or a single bond, and R ¹ and R ² each independently represents a hydrogen atom, an alkyl group, a phenyl group or a substituted phenyl group. P represents an integer of 1 to 50. ]

R ¹ and R ² are preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a phenyl group, or a substituted phenyl group. The substituent that may be bonded to the substituted phenyl group is 1 to 3 carbon atoms. And an alkyl group, a halogen atom, and the like. In the aliphatic diamine represented by the general formula (5), X in the general formula (5) is preferably an ether group from the viewpoint of obtaining a resin composition having both a low elastic modulus and a high Tg. Examples of such aliphatic diamines include Jeffamine D-400 (trade name, amine equivalent 400, manufactured by Mitsui Chemicals Fine Co., Ltd.) and Jeffamine D-2000 (trade name, amine equivalent 1000, manufactured by Mitsui Chemicals Fine Co., Ltd.). Etc. can be illustrated.

  As the diisocyanate used for producing the polyamide-imide resin, a compound represented by the following general formula (6) can be used.

［式（６）中、Ｄは少なくとも１つの芳香環を有する２価の有機基、又は２価の脂肪族炭化水素基である。］

[In Formula (6), D is a divalent organic group or divalent aliphatic hydrocarbon group having at least one aromatic ring. ]

In the general formula (6), D _{is, -C 6 H 4 -CH 2 -C} 6 H 4 - , a group represented by tolylene group, a naphthylene group, a hexamethylene group, 2,2,4-trimethylhexamethylene It is preferably at least one group selected from the group consisting of a group and an isophorone group.

  Among the diisocyanates, aromatic diisocyanates include 4,4′-diphenylmethane diisocyanate (MDI), 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene-1,5-diisocyanate, 2,4-tolylene diisocyanate. Rendimer and the like can be exemplified, and MDI is preferable among them. By using MDI as the aromatic diisocyanate, the flexibility of the resulting polyamideimide resin can be improved.

  Among the diisocyanates, examples of the aliphatic diisocyanate include hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and isophorone diisocyanate.

  When the aromatic diisocyanate and the aliphatic diisocyanate are used in combination, it is preferable to add the aliphatic diisocyanate to about 5 to 10 mol% with respect to the aromatic diisocyanate. By using an aromatic diisocyanate and an aliphatic diisocyanate in combination, the heat resistance of the resulting polyamideimide resin can be further improved.

  The thermosetting resin composition preferably contains an additive flame retardant for the purpose of improving flame retardancy.

  As the flame retardant, a filler containing phosphorus is preferable, and as the phosphorus-containing filler, OP930 (manufactured by Clariant, trade name, phosphorus content 23.5% by mass), HCA-HQ (manufactured by Sanko Co., Ltd., trade name, Phosphorus content 9.6% by mass), melamine polyphosphate PMP-100 (manufactured by Nissan Chemical Co., Ltd., trade name, phosphorus content 13.8% by mass), PMP-200 (manufactured by Nissan Chemical Co., Ltd., trade name, phosphorus) Content 9.3 mass%), PMP-300 (manufactured by Nissan Chemical Co., Ltd., trade name, phosphorus content 9.8 mass%) and the like.

  Substrate 100 with metal foil is a main component of a laminate obtained by laminating a thermosetting resin composition on one main surface or both main surfaces of a fiber base impregnated with a thermosetting resin composition. It can be obtained by a production method in which a metal foil is further provided on the surface and heated and pressed. The insulating substrate 20 can be obtained by a manufacturing method in which the metal foil of the substrate 100 with metal foil is removed by etching or the like. The printed wiring board can be obtained by a manufacturing method in which wiring is formed on the substrate 100 with metal foil by a subtractive method or the like.

  Below, the detail of the manufacturing method of the board | substrate 100 with a metal foil, the insulating board | substrate 20, and a printed wiring board concerning one Embodiment of this invention is demonstrated.

  First, a resin component such as a thermosetting resin and an additional flame retardant such as a curing agent, a curing accelerator, and a phosphorus-containing filler added as necessary are mixed, dissolved, and dispersed in an organic solvent. Thus, a resin varnish can be produced. Any organic solvent may be used as long as it can dissolve the resin. For example, dimethylacetamide, dimethylformamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, γ-butyllactone, sulfolane, cyclohexanone, and the like can be used.

  A prepreg can be obtained by impregnating the produced resin varnish into a fiber base material and drying in a range of, for example, 80 ° C. to 180 ° C. The thermosetting resin composition impregnated in the fiber base material of the prepreg can be 60% or more by mass ratio with respect to the fiber base material. The drying time can be determined in consideration of the gelation time of the resin varnish, and is not particularly limited.

  The production conditions of the prepreg are not particularly limited, but the volatile component remaining in the thermosetting resin composition impregnated in the fiber base material after drying is 20% by mass or less of the thermosetting resin composition. It is preferable that

  The amount of the resin varnish impregnated into the fiber base material after drying is such that the mass of the resin varnish solid content is 30 to 80% by mass with respect to the total mass of the solid content in the resin varnish and the fiber base material. It is preferable.

  The metal foil with resin can be obtained by applying the above-mentioned resin varnish on the metal foil and drying it at 80 ° C. to 180 ° C., for example. The drying time can be set in consideration of the gelation time of the resin varnish.

  The production conditions of the resin-coated metal foil are not particularly limited, but it is preferable that 80% by mass or more of the solvent used in the production of the resin varnish is volatilized. The resin-coated metal foil is preferably in a B-stage state in which the resin varnish is semi-cured, but may be in a cured C-stage state. In addition, it is preferable that the thickness of the thermosetting resin composition on the metal foil after drying is 5-60 micrometers.

  Next, a metal foil with resin can be laminated on the main surface of the prepreg to obtain a laminate. The metal foil with resin can be laminated on the main surface on one side or both main surfaces of the prepreg. By laminating another metal foil with resin on the metal foil with resin laminated on the prepreg, a plurality of metal foils with resin can be laminated on the main surface of the prepreg. In addition, only metal foil can be laminated | stacked on a prepreg, or a thermosetting resin composition and metal foil can also be laminated | stacked separately.

  The resulting laminate is heated and pressed at a temperature usually in the range of 150 ° C. to 280 ° C., preferably in the range of 180 ° C. to 250 ° C., usually in the range of 0.5 to 20 MPa, preferably 1 to 8 MPa. By doing so, the board | substrate 100 with a metal foil can be manufactured.

  The printed wiring board can be obtained by performing normal circuit processing (such as a subtractive method) for forming a printed circuit on the substrate 100 with metal foil. The insulating substrate 20 can be obtained by removing the outermost metal foil 10 of the substrate 100 with metal foil by a normal processing method such as etching. The printed wiring board can also be obtained by forming wiring on the insulating substrate 20 by a normal processing method such as an additive method.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

Example 1
First, a 1-liter separable flask equipped with a 25 ml water quantitative receiver with a cock connected to a reflux condenser, a thermometer, and a stirrer was prepared.

  In this separable flask, 14.9 g (0.06 mol) of DDS (diaminodiphenylsulfone) as a diamine having two or more aromatic rings, and reactive silicone oil KF-8010 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a siloxane diamine, Product name, amine equivalent 430) 43.0 g (0.05 mol), Jeffamine D2000 (Mitsui Chemical Fine Co., Ltd., trade name, amine equivalent 1000) 72.0 g (0.36 mol), Wandamine (New Japan Rika) Product name: 11.3 g (0.054 mol), TMA (trimellitic anhydride) 80.7 g (0.42 mol), NMP (N-methyl-2-pyrrolidone) as an aprotic polar solvent 589 g was charged to obtain a mixed solution.

  The mixed solution was stirred in a separable flask at 80 ° C. for 30 minutes. After completion of the stirring, 150 ml of toluene which can be azeotroped with water was put into the separable flask, the temperature was raised, and the mixture was refluxed at 160 ° C. for 2 hours.

  After confirming that 7.2 ml or more of water has accumulated in the moisture determination receiver and that no water distills out, remove the distillate that has accumulated in the moisture determination receiver. The temperature of the mixed solution in the bull flask was raised to about 190 ° C., and toluene was removed.

  After removing the toluene, the mixed solution is returned to room temperature, and 55.1 g (0.22 mol) of MDI (4,4′-diphenylmethane diisocyanate) as an aromatic diisocyanate is put into a separable flask and reacted at 190 ° C. for 2 hours. It was. After completion of the reaction, an NMP solution of polyamideimide resin (resin solid content 32% by mass) was obtained.

  250.0 g of the NMP solution, 40.0 g of a dimethylacetamide solution (Nippon Kayaku Co., Ltd., trade name: NC3000) having an epoxy resin solid content of 50% by mass, and 0.2 g of 2-ethyl-4-methylimidazole The mixture was mixed and stirred for 1 hour until the resin became uniform, and left at room temperature for 24 hours for defoaming to obtain a resin varnish.

  The obtained resin varnish was applied on one side of a 12 μm thick electrolytic copper foil (Furukawa Electric Co., Ltd., trade name: F2-WS-12) and dried by heating at 150 ° C. for 15 minutes, A resin-coated copper foil having a thermosetting resin composition thickness of 50 μm was prepared.

  The obtained resin varnish was impregnated into a glass cloth (manufactured by Nittobo Co., Ltd., trade name: WEX1015, thickness: 15 μm) and then dried by heating at 150 ° C. for 15 minutes, so that the content of the thermosetting resin composition was A 70% by mass prepreg was produced.

  The produced resin-coated copper foil was laminated on both sides of the produced prepreg so that the resin layer was in contact with the prepreg to obtain a laminate. Thereafter, the laminate was pressed under the conditions of a degree of vacuum of 40 mmHg, a pressure of 2 MPa, a temperature of 230 ° C., and a curing time of 1 hour to prepare a double-sided copper-clad laminate, that is, a substrate with metal foil.

(Example 2)
In a 1 liter separable flask equipped with a moisture determination receiver similar to that used in Example 1, a thermometer, and a stirrer, 14.9 g of DDS (diaminodiphenylsulfone) as a diamine having two or more aromatic rings ( 0.06 mol), 51.6 g (0.06 mol) of reactive silicone oil KF-8010 (trade name, amine equivalent 430, manufactured by Shin-Etsu Chemical Co., Ltd.) as siloxane diamine, and Jeffamine D2000 (Mitsui Chemical Fine Co., Ltd.) Product, trade name, amine equivalent 1000) 52.0 g (0.26 mol), Wandamin (manufactured by Shin Nippon Chemical Co., Ltd., trade name) 11.3 g (0.054 mol), TMA (trimellitic anhydride) 80. 7 g (0.42 mol) and NMP (N-methyl-2-pyrrolidone) 575 as an aprotic polar solvent A condenser. Then, to obtain a mixed solution.

  The mixed solution was stirred in a separable flask at 80 ° C. for 30 minutes. After completion of the stirring, 150 ml of toluene which can be azeotroped with water was put into the separable flask, the temperature was raised, and the mixture was refluxed at 160 ° C. for 2 hours.

  After confirming that 7.2 ml or more of water has accumulated in the moisture determination receiver and that no water distills out, remove the distillate that has accumulated in the moisture determination receiver. The temperature of the mixed solution in the bull flask was raised to about 190 ° C., and toluene was removed.

  After removing toluene, the mixed solution was returned to room temperature and 55.1 g (0.22 mol) of MDI (4,4′-diphenylmethane diisocyanate) as an aromatic diisocyanate was charged into a separable flask and reacted at 190 ° C. for 2 hours. It was. After completion of the reaction, an NMP solution of polyamideimide resin (resin solid content 32% by mass) was obtained.

  250.0 g of the NMP solution, 40.0 g of a dimethylacetamide solution (Nippon Kayaku Co., Ltd., trade name: NC3000) having an epoxy resin solid content of 50% by mass, and 0.2 g of 2-ethyl-4-methylimidazole The mixture was mixed and stirred for 1 hour until the resin became uniform, and left at room temperature for 24 hours for defoaming to obtain a resin varnish.

  A resin-coated copper foil was produced in the same manner as in Example 1 using the obtained resin varnish. Next, the obtained resin varnish was impregnated into a glass cloth (manufactured by Nittobo Co., Ltd., trade name: WEX1027, thickness: 19 μm) and dried by heating at 150 ° C. for 15 minutes to obtain a thermosetting resin composition. A prepreg having a content of 70% by mass was produced.

  A double-sided copper clad laminate was produced in the same manner as in Example 1 using the produced copper foil with resin and prepreg.

(Example 3)
Epoxy resin (Dainippon Ink Co., Ltd., trade name: EPICLON 153) 340.0 g, curing agent (Teijin Chemicals Co., Ltd., trade name: FG-2000) 181 g, and curing accelerator (Shikoku Kasei Kogyo Co., Ltd., product) Name: 2PZ-CN) 1.0 g was dissolved in 600.0 g of methyl isobutyl ketone, and then an acrylic resin (15 mass%)-containing methyl ethyl ketone solution (manufactured by Nagase ChemteX Corporation, trade name: HTR-860-P3, acrylic) Resin weight average molecular weight 850,000) 287.0 g was added, and further stirred for 1 hour to obtain a resin varnish.

  A resin-coated copper foil was produced in the same manner as in Example 1 using the obtained resin varnish. Next, the obtained resin varnish was impregnated into a glass cloth (manufactured by Nittobo Co., Ltd., trade name: WEX1035, thickness: 30 μm) and dried by heating at 150 ° C. for 15 minutes to obtain a thermosetting resin composition. A prepreg having a content of 65% by mass was produced.

  A double-sided copper clad laminate was produced in the same manner as in Example 1 using the produced copper foil with resin and prepreg.

Example 4
300 g of epoxy resin (made by Nippon Kayaku Co., Ltd., trade name: BREN-S), 181.0 g of a curing agent (made by Teijin Chemicals Ltd., trade name: FG-200), and a curing accelerator (made by Shikoku Kasei Kogyo Co., Ltd.) , Trade name: 2PZ-CN) 1.0 g dissolved in methyl isobutyl ketone 600.0 g, acrylic resin (15% by mass) -containing methyl ethyl ketone solution (manufactured by Nagase ChemteX Corporation, trade name: HTR-860-P3) Acrylic resin weight average molecular weight 850,000) 287.0 g was added, and further stirred for 1 hour to obtain a resin varnish.

  A resin-coated copper foil was produced in the same manner as in Example 1 using the obtained resin varnish. Next, the obtained resin varnish was impregnated into a glass cloth (manufactured by Nittobo Co., Ltd., trade name: WEX1027, thickness: 19 μm) and dried by heating at 150 ° C. for 15 minutes to obtain a thermosetting resin composition. A prepreg having a content of 70% by mass was produced.

  A double-sided copper clad laminate was produced in the same manner as in Example 1 using the produced copper foil with resin and prepreg.

(Comparative Example 1)
In the same manner as in Example 2, a prepreg having a thermosetting resin composition content of 70% by mass was produced, and 8 prepregs were laminated to produce a prepreg laminate. Furthermore, an electrolytic copper foil having a thickness of 12 μm (product name F2-WS-12, manufactured by Furukawa Electric Co., Ltd.) is laminated on both surfaces of the prepreg laminate in the same direction as the prepreg lamination direction, and the degree of vacuum is 40 mmHg, the pressure is 2 MPa, It pressed on the conditions of temperature 230 degreeC and hardening time 1 hour, and produced the double-sided copper clad laminated board of the structure where the prepreg laminated body was pinched | interposed into the electrolytic copper foil.

(Comparative Example 2)
A commercially available double-sided copper-clad laminate (manufactured by Hitachi Chemical Co., Ltd., trade name: E-679) was prepared.

(Comparative Example 3)
A commercially available non-adhesive copper-clad laminate for flexible printed circuit board (manufactured by Nippon Steel Chemical Co., Ltd., trade name: Espanex) was prepared.

  The copper foils of the double-sided copper-clad laminates of Examples 1 to 4 and Comparative Examples 1 to 2 and the adhesiveless copper-clad laminate for flexible printed circuit boards of Comparative Example 3 were prepared using an aqueous ammonium persulfate solution (130 g / l) at 40 ° C. The entire surface was removed by etching to obtain an insulating substrate.

  The thickness of each insulating substrate and the maximum thickness of the resin substrate of each insulating substrate in the lamination direction of the fiber substrate reinforcing layer and the resin layer are measured by observing a cross section of the insulating substrate with an optical microscope. did. From the obtained measured value, the ratio of the maximum thickness of the fiber base material to the total thickness of the insulating substrate in the stacking direction of the fiber base material reinforcing layer and the resin layer was calculated.

  From the mass of the insulating substrate actually measured with a scale and the mass of the fiber base material measured in advance before forming the insulating substrate, the ratio (content ratio) of the mass of the fiber base material to the entire insulating substrate was determined. The results were as shown in Table 1.

  The bendability of the insulating substrate was evaluated as follows. The copper foil of the obtained double-sided copper-clad laminate was etched with a 40 ° C. aqueous ammonium persulfate solution (130 g / l) to remove the entire surface to obtain a test substrate. A metal rod having a diameter of 1 mm is brought into contact with the main surface inside the bent portion of the test substrate, the test substrate is bent 180 degrees along the metal rod, and cracks and breakage of the test substrate are observed. I investigated. A sample having no occurrence of cracking or breaking was evaluated as A, and a sample having cracking or breaking was evaluated as C. The evaluation results are as shown in Table 1.

The dimensional change at the time of moisture absorption of the insulating substrate was evaluated as follows. The copper foil of the 250 mm square double-sided copper-clad laminate was etched with a 40 ° C. aqueous ammonium persulfate solution (130 g / l) to remove the entire surface to obtain a substrate for moisture absorption test. A fixed point was provided at the end of the moisture absorption test substrate, and the length (L1) of one side of the main surface of the moisture absorption test substrate was measured. Thereafter, the substrate for moisture absorption test was stored in an atmosphere of 40 ° C. and 90% RH for 96 hours, and the length (L2) of the one side was measured after the storage. And the moisture absorption dimensional change rate (%) was calculated | required by following General formula (7). The calculation results are shown in Table 1.
(L2-L1) / L1 × 100 (%) (7)

  The dust resistance of the insulating substrate was evaluated as follows. The insulating substrate was cut into a predetermined size with a cutter and examined for the presence of resin powder. The case where no resin powder was generated was evaluated as A, and the case where resin powder was generated was evaluated as C, and A was determined to be acceptable. The evaluation results are as shown in Table 1.

  The insulating substrate obtained from the double-sided copper-clad laminates of Examples 1 to 4 had good bendability and dust resistance. Moreover, the dimensional change at the time of moisture absorption of this insulating board | substrate is smaller than the insulating board | substrate obtained from the non-adhesive copper clad laminated board for flexible printed circuit boards of the comparative example 3 which is not equipped with the glass cloth, Good dimensional stability showed that.

  As described above, the insulating substrate obtained from the double-sided copper-clad laminates of Examples 1 to 4 has the same foldability as that of the flexible printed circuit board, that is, flexibility, moisture absorption, and excellent dimensional stability and dust generation resistance. It was confirmed that the

It is a fragmentary sectional view of a substrate with metal foil and an insulating substrate concerning one embodiment of the present invention.

Explanation of symbols

  3 ... fiber base material reinforcing layer, 5 ... resin layer, 10 ... metal foil, 20 ... insulating substrate.

Claims (8)

An insulating substrate comprising a fiber base material and a resin composition,
The insulating substrate whose maximum thickness of the said fiber base material is 30 micrometers or less, and whose content rate of the said fiber base material is 17 mass% or less of the whole.   The insulating substrate according to claim 1, wherein the ratio of the maximum thickness of the fiber base material to the entire thickness is 0.05 to 0.20. The resin composition comprises a cured product of a thermosetting resin composition,
The insulating property according to claim 1 or 2, wherein the resin composition has a tensile modulus of elasticity of 0.5 to 10 GPa at 20 to 30 ° C, and a coefficient of thermal expansion at a temperature equal to or lower than the glass transition point of 100 to 400 ppm. substrate.   The insulating substrate according to claim 3, wherein the thermosetting resin composition includes a polymer having an amide group and having a weight average molecular weight of 20,000 to 50,000.   The insulating substrate according to claim 3 or 4, wherein the thermosetting resin composition includes one or both of an epoxy resin and an acrylic resin.   A board | substrate with a metal foil provided with the insulating board | substrate as described in any one of Claims 1-5, and the metal foil provided on the main surface of the said insulating board | substrate.   The printed wiring board obtained from the board | substrate with a metal foil of Claim 6. The printed wiring board obtained from the insulating substrate as described in any one of Claims 1-5.

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