JP5577837B2 - Metal foil-clad laminate, method for producing the same, and printed wiring board using the same - Google Patents

Description

  The present invention relates to a metal foil-clad laminate, a manufacturing method thereof, and a printed wiring board using the same.

  In the production of a printed wiring board, when a printed circuit is formed by a subtractive method, a metal foil-clad laminate is used. This metal foil-clad laminate is generally made of a resin composition (insulating resin) having electrical insulation and a predetermined number of prepregs containing a fiber base material in the matrix, and a copper foil on the surface (one side or both sides). It is manufactured by stacking and pressing metal foils such as the like. As the insulating resin, for example, a thermosetting resin such as a phenol resin, an epoxy resin, a polyimide resin, a bismaleimide-triazine resin or the like is widely used, but a thermoplastic resin such as a fluororesin or a polyphenylene ether resin is used. Sometimes used.

  A printed wiring board obtained using such a metal foil-clad laminate is mounted on various electronic devices. In recent years, with the widespread use of information terminal devices such as personal computers and mobile phones, printed wiring boards mounted on them have been reduced in size and density. And the mounting form of the chip component (chip) on the printed wiring board is changing from the pin insertion type to the surface mounting type, and further to the area array type represented by BGA (ball grid array) using a plastic substrate. .

  For example, when a bare chip such as a BGA is directly mounted, the connection between the chip and the substrate is generally performed by wire bonding by thermosonic bonding. In this case, the substrate on which the bare chip is mounted is exposed to a high temperature of 150 ° C. or higher. Therefore, a certain degree of heat resistance is required for the insulating resin used for the prepreg that is a constituent material of the substrate.

  Also, in the printed wiring board, there is a case where so-called repairability is required in which a chip once mounted is removed, but the same level of heat as that during mounting is applied during this repair. Then, since the chip is mounted again on the substrate, further heat treatment is performed. For this reason, a substrate that requires repairability is required to have cyclic thermal shock resistance at high temperatures. However, when a prepreg using a conventional insulating resin is used, peeling tends to occur between the fiber base material and the resin due to such cyclic thermal shock.

  Therefore, in order to reduce the above inconvenience, a prepreg is disclosed in which a fiber base material is impregnated with a resin composition containing a polyamideimide resin as an essential component (see Patent Document 1). In addition, a heat-resistant base material in which a fiber base material is impregnated with a resin composition composed of a silicone-modified polyimide resin and a thermosetting resin has been proposed (see Patent Document 2).

  As the printed wiring board becomes thinner, a thinner substrate has been developed as a fiber substrate. For example, glass cloths having a thickness of about 10 μm are being supplied among glass cloths used as fiber substrates. By impregnating these thin fiber substrates with the resin composition, thin prepregs, and further thin metal foil-clad laminates using the same, have been developed. When such thin fiber substrates are used, The resulting metal foil-clad laminate and printed wiring board tend to be warped. If warpage occurs in a metal foil-clad laminate, circuit formability deteriorates during subsequent circuit processing, and if warpage occurs in the printed wiring board, chip component mounting properties and reliability are reduced. And inconveniences such as being likely to occur.

  Furthermore, recently, along with further downsizing and higher performance of electronic devices, it has been required to accommodate printed wiring boards on which components are mounted in a limited space. As such a method, a method is known in which a plurality of printed wiring boards are arranged in multiple stages and these are connected to each other by a wire harness or a flexible wiring board. Further, a method is known in which a flexible substrate based on polyimide and a conventional rigid substrate are multilayered to form a rigid-flex substrate.

  In order to cope with downsizing and high performance of electronic devices, a printed wiring board that can be bent arbitrarily and can be stored at a high density in a limited space plays an important role. Therefore, in order to provide a foldable printed wiring board, a prepreg in which a fiber base material of 50 μm or less is impregnated with a thermosetting resin having flexibility after curing can be bent and can be made thin. Multilayer materials have been proposed (see Patent Documents 3 and 4).

JP 2003-55486 A JP 2003-55486 A JP 2005-272799 A JP 2003-274150 A

  However, since the multilayer material using the foldable prepreg as described above tends to have low resistance to tearing when it is thinned, and it is difficult to sufficiently suppress the occurrence of warping, printed wiring In many cases, it was difficult to manufacture the plate.

  Accordingly, the present invention has been made in view of such circumstances, and provides a metal foil-clad laminate that has sufficient heat resistance, excellent tear resistance, little warpage, and can be bent. The purpose is to do. Moreover, it aims at providing the manufacturing method of such a metal foil tension laminated board, and the printed wiring board using this metal foil tension laminate.

  In order to achieve the above object, a metal foil-clad laminate of the present invention comprises a first metal foil, a first non-thermoplastic polyimide resin layer, a thermosetting resin, and a fiber substrate having a thickness of 25 μm or less. The base material layer to be formed, the second non-thermoplastic polyimide resin layer, and the second metal foil are provided in this order, and the thickness of the base material layer is 100 μm or less, and the first non-thermoplastic polyimide The thickness of the resin layer and the second non-thermoplastic polyimide resin layer is 1 μm or more and 10 μm or less, and the thickness of the first non-thermoplastic polyimide resin layer and the thickness of the second non-thermoplastic polyimide resin layer The absolute value of the difference is less than 3 μm.

  In the metal foil-clad laminate of the present invention, a non-thermoplastic polyimide resin layer and a metal foil are sequentially laminated on both sides of a base material layer in which a fiber base material is impregnated with a thermosetting resin and both are substantially integrated. It will have the structure.

  And in this way, by having a non-thermoplastic polyimide resin layer on both sides of a base material layer containing a thermosetting resin, the metal foil-clad laminate of the present invention uses a thin fiber base material. Even a structure that can be bent arbitrarily can exhibit excellent tear resistance in addition to high heat resistance.

  Furthermore, as a result of investigations by the present inventors, it has been found that the occurrence of warpage in a metal foil-clad laminate is conventionally caused by a variation in the thickness of the resin layers on both sides of the fiber substrate. . On the other hand, the metal foil-clad laminate of the present invention has very little warpage because the difference in thickness of the non-thermoplastic polyimide resin layers disposed on both sides of the fiber base is within the above specified range. It becomes.

  In the metal foil-clad laminate of the present invention, the thicknesses of the first non-thermoplastic polyimide resin layer and the second non-thermoplastic polyimide resin layer are 1 μm or more and 10 μm or less. When the thickness of the non-thermoplastic polyimide resin layer is in such a range, while the overall thickness of the metal foil-clad laminate is sufficiently thin, high heat resistance and tear resistance are obtained, and warpage is reduced. can do.

  The absolute value of the difference between the thickness of the first non-thermoplastic polyimide resin layer and the thickness of the second non-thermoplastic polyimide resin layer is less than 3 μm. Even if the difference in thickness between the non-thermoplastic polyimide resin layers disposed on both sides of the base material layer is so small, the metal foil-clad laminate can be extremely warped.

  Furthermore, the fiber substrate has a thickness of 25 μm or less. By using such a fiber base material, the metal foil-clad laminate can be made sufficiently thin and have excellent bendability. Among these, glass cloth is suitable as the fiber base material.

  Furthermore, the base material layer has a thickness of 100 μm or less. When the thickness of the base material layer exceeds 100 μm, the heat resistance tends to decrease. From this viewpoint, the preferable thickness of the base material layer is 80 μm or less.

  Further, the non-thermoplastic polyimide resin constituting the first non-thermoplastic polyimide resin layer and the second non-thermoplastic polyimide resin layer is an anhydrous form of at least one of biphenyltetracarboxylic acid anhydride and pyromellitic acid anhydride. And at least one diamine selected from the group consisting of 4,4′-diaminodiphenyl ether, p-phenylenediamine, and m-phenylenediamine. By using these non-thermoplastic polyimide resins, the heat resistance and tear resistance of the metal foil-clad laminate tend to be further improved.

  On the other hand, the thermosetting resin preferably contains at least one resin selected from the group consisting of a resin having a glycidyl group, a resin having an amide group, and an acrylic resin. When the thermosetting resin is one of these, the heat resistance and tear resistance of the metal foil-clad laminate are further improved. In particular, when these thermosetting resins are used in combination with the non-thermoplastic polyimide resin described above, such characteristics tend to be very good.

  The present invention also provides a printed wiring board obtained using the metal foil-clad laminate of the present invention. That is, the printed wiring board of the present invention is obtained by processing the first metal foil and / or the second metal foil in the metal foil-clad laminate of the present invention into a circuit. Since such a printed wiring board is obtained by using the metal foil-clad laminate of the present invention, even if it is thin, it has excellent heat resistance and tear resistance and is less likely to warp.

  Moreover, the manufacturing method of the metal foil-clad laminate according to the present invention includes a first laminate including a first metal foil, a first non-thermoplastic polyimide resin layer, and a first thermosetting resin layer in this order; A second laminate including a second metal foil, a second non-thermoplastic polyimide resin layer, and a second thermosetting resin layer in this order, a first thermosetting resin layer, and a second thermosetting It has the process of superposing | stacking through a fiber base material so that an adhesive resin layer may face, and heating and pressurizing.

  In the manufacturing method of the present invention, since the heating and pressurization are performed after the fiber substrate is sandwiched between the first and second laminates, the first and second non-layers disposed on both sides of the fiber substrate are performed. It is easy to equalize the thickness of the thermoplastic polyimide resin layer. Accordingly, it is possible to greatly reduce the occurrence of warpage due to the variation in the thickness of the resin layers on both sides of the fiber base material. Further, according to the production method of the present invention, since the resin layer derived from the first and second non-thermoplastic polyimide resin layers is formed, a metal foil-clad laminate having excellent heat resistance and tear resistance is obtained. Be able to.

  In the production method of the present invention, the absolute value of the difference between the thickness of the first non-thermoplastic polyimide resin layer and the thickness of the second non-thermoplastic polyimide resin layer is preferably less than 3 μm. If it carries out like this, it will become possible to further reduce generation | occurrence | production of the curvature of a metal foil clad laminated board.

  According to the present invention, it is possible to provide a metal foil-clad laminate that has sufficient heat resistance, excellent tear resistance, little warpage, and can be bent. In addition, it is possible to provide a method for producing such a metal foil-clad laminate and a printed wiring board using the metal foil-clad laminate.

It is process drawing which shows the manufacturing method of a metal foil tension laminated board typically. It is a figure which shows the cross-section of the printed wiring board of suitable embodiment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as necessary.

[Method for producing metal foil-clad laminate]
First, a method for manufacturing a metal foil-clad laminate according to a preferred embodiment will be described. FIG. 1 is a process diagram schematically showing a method for producing a metal foil-clad laminate of this embodiment. In the manufacturing method of the present embodiment, first, as shown in FIG. 1A, a metal foil 11 (first metal foil), a non-thermoplastic polyimide resin layer 12 (first non-thermoplastic polyimide resin layer), and Laminate 10 (first laminate) comprising thermosetting resin layer 13 (first thermosetting resin layer) in this order, metal foil 21 (second metal foil), non-thermoplastic polyimide resin layer 22 A laminate 20 (second laminate) provided with (second non-thermoplastic polyimide resin layer) and thermosetting resin layer 23 (second thermosetting resin layer) in this order is prepared. Then, the laminated body 10 and the laminated body 20 are arranged to face each other with the thermosetting resin layer 13 and the thermosetting resin layer 23 facing each other, and the fiber base material 30 is arranged therebetween.

  Next, as shown in FIG. 1 (b), the laminated body 10 and the laminated body 20 are superposed so as to sandwich the fiber base material 30, and the obtained laminated body is heated and pressurized in the laminating direction, A metal foil-clad laminate 100 is obtained. By such heating and pressurization, each layer of the laminate is sufficiently adhered. At this time, the thermosetting resin constituting the thermosetting resin layers 13 and 23 is impregnated in the fiber base material 30 and cured by heating. And thereby, the thermosetting resin layers 13 and 23 and the fiber base material 30 are almost integrated, and the fiber base material is contained in the cured product of the thermosetting resin constituting the thermosetting resin layers 13 and 23. The base material layer 25 has a structure in which 30 is arranged.

  The heating and pressurizing conditions are such that each layer can be sufficiently adhered, the non-thermoplastic polyimide resin layers 12 and 22 are not softened, and the thermosetting resin layers 13 and 23 are sufficiently cured. It is preferable to do.

  From the above viewpoint, the heating is preferably performed in a temperature range of 150 to 280 ° C, and more preferably in a temperature range of 180 ° C to 250 ° C. When the heating temperature is too low, the thermosetting resin is not sufficiently cured and the heat resistance tends to be lowered. On the other hand, if the heating temperature is too high, the heat resistance tends to decrease due to deterioration of the thermosetting resin.

  Moreover, it is preferable to perform pressurization in the range of 0.5-20 MPa, and it is more preferable to carry out in the range of 1-8 MPa. If this pressure is too low, impregnation of the thermosetting resin into the fiber substrate becomes insufficient, and voids may be easily generated. On the other hand, if the pressure is too high, the thickness of the base material tends to deviate from a desired design value.

  Hereinafter, the laminates 10 and 20 and the fiber base material 30 used in the method for manufacturing the metal foil-clad laminate 100 will be described in detail.

(Fiber substrate)
The fiber base material 30 can be applied without particular limitation as long as it can be applied as a substrate material in a metal foil-clad laminate or a printed wiring board, and a fiber base material such as a woven fabric or a non-woven fabric is used. Examples of the fiber base material include glass, alumina, boron, silica-alumina glass, silica glass, tyrano, silicon carbide, silicon nitride, zirconia, and other inorganic fibers, aramid, polyetheretherketone, polyetherimide, polyethersulfone , Organic fibers such as carbon and cellulose, or mixed papers thereof. Of these, a glass fiber woven fabric (glass cloth) is preferable.

  As the fiber base material, a glass cloth having a thickness of 25 μm or less is particularly preferable, and a glass cloth having a thickness of 20 μm or less is more preferable. By using a glass cloth having a thickness of 25 μm or less, the obtained metal foil-clad laminate has excellent flexibility and can be used to produce a printed wiring board that can be arbitrarily bent.

(Laminate)
Corresponding configurations in the laminate 10 and the laminate 20, that is, the metal foil 11 and the metal foil 21, the non-thermoplastic polyimide resin layer 12 and the non-thermoplastic polyimide resin layer 22, the thermosetting resin layer 13 and the thermosetting resin. The layers 23 may be made of the same material or different materials. However, from the viewpoint of reducing warpage of the metal foil-clad laminate, it is more preferable that these corresponding components are made of the same material.

  First, the metal foil 11 and the metal foil 21 will be described.

  As metal foil 11 and metal foil 21, what is used as a constituent material of the circuit of a printed wiring board can be applied without a restriction | limiting especially, and the metal foil which has a thickness of 5-200 micrometers is suitable. Examples of the metal foils 11 and 21 include copper foil and aluminum foil, nickel, nickel-phosphorus, nickel-tin alloy, nickel-iron alloy, lead, lead-tin alloy, etc. A composite foil having a three-layer structure in which a copper layer having a thickness of 5 to 15 μm and a copper layer having a thickness of 10 to 300 μm are provided, or a composite foil having a two-layer structure in which aluminum and a copper foil are combined can be used.

  The surface of the metal foils 11 and 21 may be roughened. For example, if the surface on the non-thermoplastic polyimide resin layer 12, 22 side is roughened, good adhesion with these layers can be obtained after heating and pressurization, high reliability, and fine circuit There is a tendency to obtain a metal foil-clad laminate that can be formed. The ten-point average roughness (Rz) of the roughened surfaces of the metal foils 11 and 21 is preferably 10 μm or less, and more preferably 5 μm or less. The 10-point average roughness (Rz) refers to the 10-point average roughness (Rz) defined in JIS B0601-1994.

  Next, the non-thermoplastic polyimide resin layer 12 and the non-thermoplastic polyimide resin layer 22 will be described.

  The non-thermoplastic polyimide resin layers 12 and 22 are layers composed of a non-thermoplastic polyimide resin. Here, the non-thermoplastic polyimide resin refers to a polymer having an imide group in a repeating unit constituting the main chain, and having no softening point in a temperature range of 300 ° C. or lower. As the “softening point”, a value measured by a stretching method with a weight of 50 mN using a thermomechanical analyzer (TMA) can be applied to a 4 mm × 20 mm film specimen.

Examples of such a non-thermoplastic polyimide resin include those having a structure represented by the following general formula (1).

In the formula (1), R ¹ represents a residue obtained by removing an amino group from a diamine or a residue obtained by removing an isocyanate group from a diisocyanate, and R ² is obtained by removing a carboxylic acid derivative portion from an aromatic tetracarboxylic acid derivative. Indicates residue. n is an integer of 1 or more. Examples of the diamine, diisocyanate, or aromatic tetracarboxylic acid derivative include those used for producing a polyamic acid described later.

The non-thermoplastic polyimide resin having the above-described structure is preferably obtained from a polyamic acid. As such a polyamic acid, what is represented by following General formula (2) is mentioned. The symbols in the following formula (2) have the same meaning as described above. By heating the polyamic acid, the reaction between the amide group and the carboxyl group in the structure proceeds to form an imide group, whereby a non-thermoplastic polyimide resin as described above is obtained.

  The polyamic acid can be obtained, for example, by reacting tetracarboxylic acid or a derivative thereof with diamine and / or diisocyanate.

  As the diamine, an aromatic diamine is preferable. Examples of the aromatic diamine include p, m or o-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,4-diaminoxylene, diaminodiurene 1,5-diaminonaphthalene, 2,6- Diaminonaphthalene, benzidine, 4,4′-diaminoterphenyl, 4,4 ′ ″-diaminoquaterphenyl, 4,4′-diaminodiphenylmethane, 1,2-bis (anilino) ethane, 4,4′-diaminodiphenyl ether 4,4′-diaminodiphenylsulfone, 2,2-bis (p-aminophenyl) propane, 2,2-bis (p-aminophenyl) hexafluoropropane, 2,6-diaminonaphthalene, 3,3-dimethyl Benzidine, 3,3′-dimethyl-4,4′-diaminodiphenyl ether, 3, '-Dimethyl-4,4'-diaminodiphenylmethane, diaminotoluene, diaminobenzotrifluoride, 1,4-bis (p-aminophenoxy) benzene, 4,4'-bis (p-aminophenoxy) biphenyl, 2,2 '-Bis [4- (p-aminophenoxy) phenyl] propane, diaminoanthraquinone, 4,4'-bis (3-aminophenoxyphenyl) diphenylsulfone, 1,3-bis (anilino) hexafluoropropane, 1,4 -Bis (anilino) octafluorobutane, 1,5-bis (anilino) decafluoropentane, 1,7-bis (anilino) decafluorobutane, 2,2-bis [4- (p-aminophenoxy) phenyl] hexa Fluoropropane, 2,2-bis [4- (3-aminophenoxy) phenyl] he Safluoropropane, 2,2-bis [4- (2-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) -3,5-dimethylphenyl] hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) -3,5-ditrifluoromethylphenyl] hexafluoropropane, p-bis (4-amino-2-trifluoromethylphenoxy) benzene, 4,4′- Bis (4-amino-2-trifluoromethylphenoxy) biphenyl, 4,4′-bis (4-amino-3-trifluoromethylphenoxy) biphenyl, 4,4′-bis (4-amino-2-trifluoro) Methylphenoxy) diphenylsulfone, 4,4′-bis (3-amino-5-trifluoromethylphenoxy) diphenyls Examples include luphone and 2,2-bis [4- (4-amino-3-trifluoromethylphenoxy) phenyl] hexafluoropropane.

Moreover, as diamine, the siloxane diamine represented by following General formula (3) can also be used. As the diamine, only this siloxane diamine may be used, or it may be used in combination with the above aromatic diamine.

In formula (3), R ³ represents a monovalent organic group, and R ⁴ represents a divalent organic group. A plurality of R ³ and R ⁴ may be the same or different. N is an integer greater than 1.

  The diisocyanate is preferably an aromatic diisocyanate obtained by the reaction of the aromatic diamine and phosgene as described above. Specific examples of the aromatic diisocyanate include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, diphenyl ether diisocyanate, phenylene-1,3-diisocyanate and the like.

  On the other hand, the tetracarboxylic acid to be reacted with diamine or diisocyanate preferably has a structure including two sets of structures having two carboxyl groups at adjacent positions. Specific examples of such tetracarboxylic acids include pyromellitic acid, 2,3,3 ′, 4′-tetracarboxydiphenyl, 3,3 ′, 4,4′-tetracarboxydiphenyl, 3,3 ′, 4. , 4′-tetracarboxydiphenyl ether, 2,3,3 ′, 4′-tetracarboxydiphenyl ether, 3,3 ′, 4,4′-tetracarboxybenzophenone, 2,3,3 ′, 4′-tetracarboxybenzophenone, 2,3,6,7-tetracarboxynaphthalene, 1,4,5,7-tetracarboxynaphthalene, 1,2,5,6-tetracarboxynaphthalene, 3,3 ′, 4,4′-tetracarboxydiphenylmethane, 2,2-bis (3,4-dicarboxyphenyl) propane, 2,2-bis (3,4-dicarboxyphenyl) hexafur Lopropane, 3,3 ′, 4,4′-tetracarboxydiphenylsulfone, 3,4,9,10-tetracarboxyperylene, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane, Examples include 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] hexafluoropropane, butanetetracarboxylic acid, cyclopentanetetracarboxylic acid, and the like. As the tetracarboxylic acid, an aromatic tetracarboxylic acid having a structure in which all carboxyl groups are bonded to an aromatic ring is preferable.

  Examples of the tetracarboxylic acid derivatives include the esterified products, acid anhydrides, and chlorides of the above-described tetracarboxylic acids. Especially, the anhydride of tetracarboxylic acid is suitable and the anhydride of aromatic tetracarboxylic acid is more preferable.

  As the polyamic acid from which a suitable non-thermoplastic polyimide resin can be obtained, the following are preferred. That is, the group consisting of m-phenylenediamine, p-phenylenediamine, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylsulfone and 2,2′-bis [4- (p-aminophenoxy) phenyl] propane. It consists of at least one diamine selected from these or diisocyanates derived from these diamines, pyromellitic acid, 3,3 ′, 4,4′-tetracarboxydiphenyl and 3,3 ′, 4,4′-tetracarboxybenzophenone. Those obtained by reaction with at least one tetracarboxylic acid selected from the group or their acid anhydrides are preferred.

  Among them, at least one selected from the group consisting of at least one of biphenyltetracarboxylic anhydride and pyromellitic anhydride, 4,4′-diaminodiphenyl ether, p-phenylenediamine, and m-phenylenediamine. Those synthesized by reacting with a seed diamine are preferred.

  In the reaction of diamine and / or diisocyanate for synthesizing polyamic acid with tetracarboxylic acid or its derivative, the molar ratio of diamine and / or diisocyanate to tetracarboxylic acid or its derivative is 0.95 to 1.05. It is preferable that When the reaction is carried out at a ratio outside this range, the molecular weight of the polyamic acid to be produced or the polyimide resin obtained therefrom may not be sufficiently increased. In that case, the obtained film may become brittle or it may be difficult to maintain the shape of the film, and the physical properties of the film may not be sufficiently obtained.

  Moreover, it is preferable to perform reaction with diamine and / or diisocyanate, and tetracarboxylic acid or its derivative (s) in a solvent, and reaction temperature can be 0-200 degreeC. As the solvent, N-methyl-2-pyrrolidone (NMP), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), dimethyl sulfate, sulfolane, γ- Examples include butyrolactone, cresol, phenol, halogenated phenol, cyclohexane, dioxane and the like.

In the reaction for synthesizing the polyamic acid, a modifying compound other than the above compounds (diamine, diisocyanate, tetracarboxylic acid, tetracarboxylic acid derivative) may be added. By adding the modifying compound, a crosslinked structure or a ladder structure can be introduced into the non-thermoplastic polyimide resin obtained from the polyamic acid. Examples of the modifying compound include compounds represented by the following general formula (4). When such a modifying compound is introduced, a structure such as a pyrrolone ring or an isoindoloquinazolinedione ring is introduced into the non-thermoplastic polyimide resin.

In the formula (4), R ⁵ represents a (2 + x) -valent aromatic organic group, Z is a group located in the ortho position with respect to the terminal amino group in the formula (4), and —NH ₂ , A group represented by —CONH ₂ , —SO ₂ NH ₂ or —OH is shown. x is 1 or 2.

  Examples of the other modifying compound include amines, diamines, dicarboxylic acids, tricarboxylic acids, and tetracarboxylic acid derivatives that include a polymerizable unsaturated bond in the molecule. Specific examples include maleic acid, nadic acid, tetrahydrophthalic acid, ethynylaniline and the like. When such a compound is used as the modifying compound, a crosslinked structure is introduced into the obtained non-thermoplastic polyimide resin.

  Next, the thermosetting resin layer 13 and the thermosetting resin layer 23 will be described.

  The thermosetting resin layers 13 and 23 are layers composed of a thermosetting resin. As the thermosetting resin, any insulating thermosetting resin used as a material for a printed wiring board substrate or the like can be used without particular limitation. Examples of the thermosetting resin include epoxy resins, polyimide resins, unsaturated polyester resins, polyurethane resins, bismaleimide resins, triazine-bismaleimide resins, phenol resins, and the like.

  Especially, as a thermosetting resin, resin which has a glycidyl group is preferable, and it is more preferable that an epoxy resin is included. Epoxy resins include polyglycidyl ethers and phthalates obtained by reacting polychlorophenols such as bisphenol A, novolac phenolic resins, orthocresol novolac phenolic resins or polyhydric alcohols 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.

  Thus, when an epoxy resin is used as a thermosetting resin, it can be cured at a temperature of 180 ° C. or lower, and thermal, mechanical, or electrical characteristics can be improved. In particular, a combination of an epoxy resin having two or more glycidyl groups and its curing agent, a combination of an epoxy resin having two or more glycidyl groups and its curing accelerator, or an epoxy resin having two or more glycidyl groups It is preferable to use a combination of a curing agent and a curing accelerator. The more glycidyl groups in the epoxy resin having a glycidyl group, the better, and more preferably 3 or more. The suitable blending amount of the epoxy resin varies depending on the number of glycidyl groups, and the blending amount can be decreased as the glycidyl group increases.

  The curing agent and curing accelerator for epoxy resin can be applied without limitation as long as they react with epoxy resin or accelerate curing. For example, amines, imidazoles, polyfunctional phenols, acid anhydrides and the like can be mentioned. Examples of amines include dicyandiamide, diaminodiphenylmethane, guanylurea and the like. Examples of the polyfunctional phenols include hydroquinone, resorcinol, bisphenol A and their halogen compounds, and novolak-type phenol resins and resol-type phenol resins that are condensates of these with formaldehyde. Examples of acid anhydrides include phthalic anhydride, benzophenone tetracarboxylic dianhydride, methyl hymic acid, and the like. Examples of the curing accelerator include alkyl group-substituted imidazole and benzimidazole as imidazoles.

  For example, in the case of amines, the amount of the curing agent or curing accelerator used is preferably such that the equivalent of the active hydrogen of the amine is approximately equal to the epoxy equivalent of the epoxy resin. Moreover, in the case of imidazole which is a hardening accelerator, it is preferably not 0.001 to 10 parts by mass with respect to 100 parts by mass of the epoxy resin empirically because it is not simply an equivalent ratio with active hydrogen. Furthermore, in the case of polyfunctional phenols and acid anhydrides, it is preferable that the phenolic hydroxyl group and carboxyl group have an amount of 0.6 to 1.2 equivalents with respect to 1 equivalent of epoxy resin. If the amount of these curing agents or curing accelerators is small, uncured epoxy resin remains, and Tg (glass transition temperature) tends to be low. If too large, unreacted curing agents and curing accelerators are present. Tends to remain, and the insulation tends to decrease.

  The thermosetting resin may further contain a high molecular weight resin component for the purpose of improving flexibility and heat resistance. Such a high molecular weight resin component can be used in addition to the epoxy resin described above or in place of the epoxy resin. Examples of the resin component include polyamide imide resin and acrylic resin.

  First, as the polyamideimide resin, a siloxane-modified polyamideimide having a siloxane structure in the resin structure is preferable. In particular, it is obtained by reacting a mixture containing diimide dicarboxylic acid obtained by reacting a mixture of diamine having 2 or more aromatic rings (aromatic diamine) and siloxane diamine with trimellitic anhydride and aromatic diisocyanate. Polyamideimide is preferred.

  Moreover, as a polyamideimide resin, what contains 70 mol% or more of polyamideimide molecules which contain 10 or more amide groups in one molecule is preferable. The content of such a polyamideimide molecule is a chromatogram (standard polystyrene conversion at 25 ° C.) obtained from GPC (gel permeation chromatography) of a polyamideimide resin, and an amide group in a unit mass determined separately from this. The number of moles (A) can be obtained. That is, from the number of moles of amide groups (A) contained in the polyamideimide resin (a) g, the value of 10 × a / A is the molecular weight (C) of the polyamideimide containing 10 amide groups in one molecule, When the region where the number average molecular weight of the chromatogram obtained by GPC is (C) or more is 70% or more, “a polyamideimide molecule containing 10 or more amide groups in one molecule is contained in an amount of 70 mol% or more. It can be determined that this is the case. As a method for quantifying the amide group, NMR, IR, hydroxamic acid-iron color reaction method, N-bromoamide method and the like can be applied. As an eluent for GPC, 0.06 mol / L of phosphoric acid and 0.03 mol / L of lithium bromide monohydrate were dissolved in a mixed solution of tetrahydrofuran / dimethylformamide (= 50/50 (volume ratio)). As the column, a column in which two GL-S300MDT-5s (trade name, manufactured by Hitachi High-Technologies Corporation) are directly connected is used.

  In the siloxane-modified polyamideimide having a siloxane structure, the mixing ratio of the aromatic ring diamine a and the siloxane diamine b used in the production thereof was a / b = 99.9 / 0.1-0 / 100 (molar ratio). It is preferable that it is a thing, it is still more preferable that it was a / b = 95 / 5-30 / 70, and it is still more preferable that it was a / b = 90 / 10-40 / 60. When the mixing ratio of the siloxane diamine b increases, the Tg of the siloxane-modified polyamideimide tends to decrease. Moreover, when the mixing ratio of siloxane diamine b decreases, the amount of varnish solvent remaining in the thermosetting resin layers 13 and 23 tends to increase when the laminates 10 and 20 are produced.

  Examples of the aromatic diamine for synthesizing the siloxane-modified polyamideimide include 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP), bis [4- (3-aminophenoxy) phenyl]. Sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, bis [4- (4-aminophenoxy) 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′-dimethylbiphenyl- , 4′-diamine, 2,2′-bis (trifluoromethyl) biphenyl-4,4′-diamine, 2,6,2 ′, 6′-tetramethyl-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, (3,3 ′ -Diamino) diphenyl ether and the like.

On the other hand, examples of the siloxane diamine include compounds represented by the following formulas (5) to (8).

  In addition, as siloxane diamine represented by the said General formula (5), X-22-161AS (amine equivalent 450), X-22-161A (amine equivalent 840), X-22-161B (amine equivalent 1500) ( Examples thereof include Shin-Etsu Chemical Co., Ltd., BY16-853 (amine equivalent 650), BY16-853B (amine equivalent 2200), and the like (manufactured by Toray Dow Corning Silicone Co., Ltd.). Examples of the siloxane diamine represented by the general formula (8) include X-22-9409 (amine equivalent 700), X-22-1660B-3 (amine equivalent 2200) (above, manufactured by Shin-Etsu Chemical Co., Ltd.), and the like. It can be illustrated.

In the synthesis of the siloxane-modified polyamideimide, aliphatic diamines may be used in combination with the above aromatic diamine and siloxane diamine. Examples of the aliphatic diamines include compounds represented by the following general formula (9).

In formula (9), X represents a methylene group, a sulfonyl group, an ether group, a carbonyl group or a single bond, R ¹ and R ² each independently represent a hydrogen atom, an alkyl group, a phenyl group or a substituted phenyl group, p is an integer of 1-50. Here, as specific examples of R ¹ and R ² , a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a phenyl group, or a substituted phenyl group is preferable, and as a substituent that may be bonded to the phenyl group, Examples thereof include an alkyl group having 1 to 3 carbon atoms and a halogen atom.

  As the aliphatic diamine, those in which X in the general formula (9) is an ether group are preferred from the viewpoint of achieving both low elastic modulus and high Tg in the siloxane-modified polyamideimide. Examples of such aliphatic diamines include Jeffamine D-400 (amine equivalent 400) and Jeffamine D-2000 (amine equivalent 1000).

As described above, the polyamide-imide resin is obtained by reacting a mixture of diamines containing these aromatic diamines, siloxane diamines, aliphatic diamines, and the like with trimellitic anhydride to obtain a mixture containing diimide dicarboxylic acid. And those obtained by reacting diisocyanate with diisocyanate. Examples of the diisocyanate to be reacted with diimide dicarboxylic acid include compounds represented by the following general formula (10).

In formula (10), D is a divalent organic group having at least one aromatic ring or a divalent aliphatic hydrocarbon group. Examples of D include a group represented by —C ₆ H ₄ —CH ₂ —C ₆ H ₄ —, a tolylene group, a naphthylene group, a hexamethylene group, a 2,2,4-trimethylhexamethylene group, and an isophorone group. At least one group selected from the group consisting of

  As the diisocyanate represented by the general formula (10), either an aliphatic diisocyanate having an aliphatic group as a group represented by D or an aromatic diisocyanate having an aromatic group as a group represented by D is used. However, it is preferable to use an aromatic diisocyanate, and it is more preferable to use both in combination.

  Examples of aromatic diisocyanates include 4,4′-diphenylmethane diisocyanate (MDI), 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene-1,5-diisocyanate, and 2,4-tolylene dimer. It can be illustrated. Of these, MDI is preferable. When MDI is used as the aromatic diisocyanate, the flexibility of the resulting polyamideimide resin can be improved.

  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. Such combined use can further improve the heat resistance of the resulting polyamideimide.

  On the other hand, as the acrylic resin used for the thermosetting resin, a homopolymer such as an acrylic acid monomer, a methacrylic acid monomer, acrylonitrile, an acrylic monomer having a glycidyl group, or a copolymer obtained by copolymerizing a plurality of these is applied. be able to. The molecular weight of the acrylic resin is not particularly limited, but is preferably 300,000 to 1,000,000, and more preferably 400,000 to 800,000 in terms of weight average molecular weight in terms of standard polystyrene. These acrylic resins are particularly preferably used in addition to an epoxy resin or a combination of an epoxy resin and a curing agent or a curing accelerator.

  An additive-type flame retardant may be added to the thermosetting resin constituting the thermosetting resin layers 13 and 23 for the purpose of improving the flame retardancy of these layers. As the additive type flame retardant, a filler containing phosphorus is preferable. As the phosphorus-containing filler, OP930 (trade name manufactured by Clariant, phosphorus content 23.5%), HCA-HQ (trade name manufactured by Sanko Co., Ltd., phosphorus content 9.6%), melamine polyphosphate PMP-100 ( Phosphorus content 13.8%) PMP-200 (Phosphorus content 9.3%) PMP-300 (Phosphorus content 9.8%, trade names made by Nissan Chemical Co., Ltd.).

  Next, the suitable manufacturing method of the laminated bodies 10 and 20 is demonstrated.

  In the production of the laminates 10 and 20, first, metal foils 11 and 21 are prepared, and a non-thermoplastic polyimide resin or a precursor thereof for forming the non-thermoplastic polyimide resin layers 12 and 22 on the surface thereof is prepared. Apply some polyamic acid. The non-thermoplastic polyimide resin or polyamic acid may be applied as it is, or may be applied in a varnish state in which these are dissolved or dispersed in a solvent.

  When using a varnish, the varnish further contains crosslinkable components such as an epoxy compound, an acrylic compound, a diisocyanate compound, and a phenol compound, and additional components such as a filler, particles, a coloring material, a leveling agent, and a coupling agent. May be. However, the amount of these additive components is preferably smaller than the amount of non-thermoplastic polyimide resin or polyamic acid. When the amount of the additive component is large, various characteristics of the obtained non-thermoplastic polyimide resin layers 12 and 22 tend to be lowered.

  The varnish and the like can be applied using a roll coater, comma coater, knife coater, doctor blade flow coater, hermetic coater, die coater, lip coater or the like. In these methods, it is preferable to apply the varnish so as to obtain a uniform thickness as much as possible by discharging the varnish from the film-forming slit.

  The concentration of the non-thermoplastic polyimide resin or precursor polyamic acid in the varnish is preferably 8 to 40% by mass. Further, the viscosity of the varnish is preferably 10 to 40 Pa · s. When the varnish has a viscosity outside this range, when the varnish is applied onto the metal foils 11 and 21, repelling or the like occurs, resulting in poor appearance of the resulting non-thermoplastic polyimide resin layers 12 and 22, or film thickness. The accuracy may decrease.

  After application of the varnish, it is preferable to dry the applied varnish layer. Drying is preferably performed so that the solvent in the varnish is removed. For example, the drying can be performed by heating the varnish layer at about 100 to 160 ° C. In drying, for example, it is preferable to remove the solvent until the ratio of the solvent contained in the varnish is preferably 1 to 60% by mass, more preferably 25 to 40% by mass of the whole. Drying may be performed under a reduced-pressure atmosphere or a reducing atmosphere as described later, in addition to the air.

  If the ratio of the solvent contained in the varnish after drying (varnish layer) is lower than 1% by mass, the non-thermoplastic polyimide resin layer formed from the varnish tends to shrink in the subsequent steps, and the resulting metal foil tension There is a risk that warpage is likely to occur in the laminate 100. Moreover, when the ratio of a solvent exceeds 60 mass%, when further heating as described later is performed, foaming may occur and the appearance may be poor, or handleability may be reduced due to excessive tack.

  The dried varnish layer may be further heated in a reducing atmosphere. Heating in a reducing atmosphere is preferably performed at, for example, 250 to 550 ° C, and more preferably 250 to 400 ° C. Moreover, as a reducing atmosphere, the atmosphere which consists of mixed gas containing nitrogen gas and 0.1 volume%-4 volume% hydrogen gas is suitable. In this reducing atmosphere, if the concentration of hydrogen gas is less than 0.1% by volume, the oxidation of the resin proceeds, and the flexibility tends to decrease. May exceed. In order to further improve the reliability, the concentration of hydrogen gas in the mixed gas is more preferably 0.1 volume% or more and less than 1 volume%.

  By heating in such a reducing atmosphere, the adhesion between the metal foils 11 and 21 and the non-thermoplastic polyimide resin layers 12 and 22 is improved, and the heat resistance of the non-thermoplastic polyimide resin layers 12 and 22 is improved. It tends to improve. For example, the peel strength at the interface between the metal foils 11 and 21 and the non-thermoplastic polyimide resin layers 12 and 22 can be set to 0.3 kN / m or more, and by a float method in a solder bath at 288 ° C. The measured solder heat resistance can be 30 seconds or more.

  Further, by heating in a reducing atmosphere, it is possible to form a non-thermoplastic polyimide resin while suppressing oxidation, whereby it is possible to obtain highly reliable non-thermoplastic polyimide resin layers 12 and 22. . Furthermore, coloring of the non-thermoplastic polyimide resin can be prevented, and workability during processing is improved.

  As described above, after applying the varnish, the solvent is removed from the varnish when the non-thermoplastic polyimide resin is used by drying and heating in a reducing atmosphere. When polyamic acid is used, the solvent is removed and the reaction between the amide group and the carboxyl group in the polyamic acid proceeds to produce a non-thermoplastic polyimide resin. As a result, the non-thermoplastic polyimide resin layers 12 and 22 are formed on the metal foils 11 and 21.

  In addition, the formation method of the non-thermoplastic polyimide resin layers 12 and 22 is not necessarily limited to the above as long as these layers are finally obtained. For example, after application of the varnish, only drying may be performed, only heating in a reducing atmosphere may be performed, or both of them may not be performed if unnecessary.

  Since the solvent in the varnish is removed after drying or heating in a reducing atmosphere, the non-thermoplastic polyimide resin layers 12 and 22 are in a state where the solvent does not substantially remain. However, the solvent does not necessarily need to be completely removed, and a trace amount of solvent may remain as long as it does not cause a problem in characteristics in the metal foil-clad laminate or the printed wiring board.

  The non-thermoplastic polyimide resin layers 12 and 22 formed as described above preferably have a thickness of 1 to 100 μm, and more preferably have a thickness of 1 to 10 μm. By setting the thickness within such a suitable range, it is possible to reduce the occurrence of warpage due to variations in the thicknesses of these layers in the metal foil-clad laminate 100, and the metal foil-clad laminate 100 and printed wiring obtained therefrom. Both the bendability of the plate and the dimensional stability against moisture absorption and temperature can be improved.

  Further, the non-thermoplastic polyimide resin layer 12 and the non-thermoplastic polyimide resin layer 22 preferably have an absolute value of a difference in thickness of less than 3 μm, and more preferably 1 μm or less. Thus, in order to reduce the difference in thickness, it is preferable to form the non-thermoplastic polyimide resin layer 12 and the non-thermoplastic polyimide resin layer 22 by using the same material and by the same method. If the absolute value of the difference in thickness between the non-thermoplastic polyimide resin layer 12 and the non-thermoplastic polyimide resin layer 22 is 3 μm or less, the occurrence of warpage due to variations in the thickness of these layers in the metal foil-clad laminate 100 is greatly increased. Can be reduced.

  Next, thermosetting resin layers 13 and 23 are further formed on the non-thermoplastic polyimide resin layers 12 and 22 formed on the metal foils 11 and 21.

  For the thermosetting resin layers 13 and 23, a varnish of a thermosetting resin for forming them was applied on the surface opposite to the metal foils 11 and 21 of the non-thermoplastic polyimide resin layers 12 and 22. Thereafter, it can be formed by drying. As a coating method, a comma coater that allows a varnish to pass between gaps or a die coater that discharges and applies a varnish flow having a flow rate adjusted from a nozzle can be used. When the thickness of the varnished coating film is 50 to 500 μm, a die coater is preferable. The coating amount of the varnish is preferably such that the thickness of the dried varnish layer (thermosetting resin layer) is 20 to 60 μm.

  The drying conditions are not particularly limited, but it is preferable to carry out so that the solvent used in the varnish volatilizes 80% by mass or more. In order to cause such volatilization, the temperature during drying is preferably adjusted within a range of 80 to 180 ° C., and the drying time is preferably set appropriately in consideration of the gelling time of the varnish.

  The thermosetting resin layers 13 and 23 are formed by applying a thermosetting resin varnish on a release substrate and drying at 80 to 180 ° C. to form a resin film. It can also be formed by laminating on the polyimide resin layers 12 and 22.

  The release substrate used in this method can be applied without particular limitation as long as it can withstand the temperature at the time of drying, for example, a resin such as a polyethylene terephthalate film with a release agent, a polyimide film, an aramid film, etc. In addition to the film, a metal foil such as an aluminum foil with a release agent can be applied. In addition, suitable methods and conditions, such as application | coating of a varnish to a mold release base material, and subsequent drying, are the same as that of apply | coating varnish as mentioned above on the non-thermoplastic polyimide resin layers 12 and 22 directly.

  By these methods, the thermosetting resin layers 13 and 23 are formed on the non-thermoplastic polyimide resin layers 12 and 22. As a result, laminates (metal foils with resin) 10 and 20 in which the non-thermoplastic polyimide resin layers 12 and 22 and the thermosetting resin layers 13 and 23 are sequentially laminated on the metal foils 11 and 21 are obtained. . And the laminated body 10 and 20 obtained in this way are piled up via the fiber base material 30 as mentioned above, and the metal foil clad laminated board 100 is obtained by heating and pressurizing.

[Metal foil-clad laminate and printed wiring board]
Next, preferred embodiments of a metal foil-clad laminate obtained by the above-described manufacturing method and a printed wiring board using the same will be described.

  As shown in FIG. 1B, the metal foil-clad laminate 100 of the preferred embodiment is cured by impregnating the fiber base material 30 with the thermosetting resin constituting the thermosetting resin layers 13 and 23. And a base material layer 25 having a structure in which the fiber base material 30 is arranged in a cured product of a thermosetting resin, and a non-thermoplastic polyimide resin on one surface of the base material layer 25 The layer 12 and the metal foil 11 have a structure in which a non-thermoplastic polyimide resin layer 22 and a metal foil 21 are formed on the other surface, respectively. In other words, the metal foil-clad laminate 100 is obtained by laminating the metal foil 11, the non-thermoplastic polyimide resin layer 12, the base material layer 25, the non-thermoplastic polyimide resin layer 22 and the metal foil 21 in this order. In this metal foil-clad laminate 100, a composite of the base material layer 25 and the non-thermoplastic polyimide resin layers 12 and 22 sandwiching the base material layer 25 becomes an insulating composite base material 50 that supports the metal foils 11 and 21. .

  In the metal foil-clad laminate 100 having such a structure, the thickness of the base material layer 25 is 100 μm or less and preferably 80 μm or less. As the thickness of the base material layer 25 is within a suitable range, the thickness can be reduced and good heat resistance can be obtained. Moreover, the thickness of the non-thermoplastic polyimide resin layer 12 and the non-thermoplastic polyimide resin layer 22 is 1 μm or more and 10 μm or less. Thereby, high heat resistance and tear resistance can be obtained while reducing the overall thickness of the metal foil-clad laminate 100, and the occurrence of warpage can be reduced.

  Furthermore, the absolute value of the difference in thickness between the non-thermoplastic polyimide resin layer 12 and the non-thermoplastic polyimide resin layer 22 is 3 μm or less, and more preferably 1 μm or less. By satisfying such conditions, it is possible to greatly reduce the occurrence of warping of the metal foil-clad laminate 100. Here, the “thickness” of the non-thermoplastic polyimide resin layers 12 and 22 in the metal foil-clad laminate 100 is the metal foils 11 and 21 and the non-thermoplastic polyimide resin layers 12 and 22 in the cross section of the metal foil-clad laminate 100. The distance between the average line of the unevenness at the interface with 22 and the average line of the unevenness at the interface between the non-thermoplastic polyimide resin layers 12 and 22 and the base material layer 25 is meant.

  A printed wiring board can be obtained by processing the metal foil 11 and / or the metal foil 21 in the metal foil-clad laminate 100 having the above structure into a predetermined circuit shape.

  FIG. 2 is a diagram showing a cross-sectional structure of a printed wiring board according to a preferred embodiment. As shown in FIG. 2, the printed wiring board 200 of the present embodiment includes a composite base material layer 50, and circuit conductors 61 and 62 provided on both surfaces of the composite base material 50, respectively. have. As described above, the composite base material 50 includes the base material layer 25 disposed between the non-thermoplastic polyimide resin layer 12 and the non-thermoplastic polyimide resin layer 22.

  The circuit conductors 61 and 62 are obtained by processing the metal foils 11 and 21 in the metal foil-clad laminate 100 into a predetermined circuit shape. The method for processing the metal foils 11 and 21 is not particularly limited, and a known circuit forming method can be applied.

  Such a metal foil-clad laminate 100 and printed wiring board 200 are both non-thermoplastic polyimide resin layers on both sides of a base material layer 25 in which a fiber base material 30 is disposed in a cured product of a thermosetting resin. A composite substrate 50 with 12 and 22 is included. Therefore, even if it is a case where the whole is thinned by using the thin fiber base material 30 and thereby has a foldable structure, it is possible to exhibit excellent tear resistance in addition to high heat resistance.

  Further, since the metal foil-clad laminate 100 and the printed wiring board 200 are obtained through the above-described method for producing a metal foil-clad laminate, the non-thermoplastic polyimide resin layer 12 provided on both sides of the base material layer 25. And the difference in thickness between the non-thermoplastic polyimide resin layer 22 is small. Therefore, in addition to the above characteristics, the occurrence of warpage that has been easy to occur due to the difference in thickness between the resin layers on both sides of the fiber base material is extremely small.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples.

[Preparation of non-thermoplastic polyimide resin precursor (polyamic acid) varnish]
While flowing nitrogen at a rate of about 300 ml / min into a 60 L stainless steel reaction kettle equipped with a thermocouple, stirrer and nitrogen inlet, 867.8 g of p-phenylenediamine, 1606.9 g of 4,4′-diaminodiphenyl ether and N— 40 kg of methyl-2-pyrrolidone was added, and these were stirred to dissolve the diamine component in N-methyl-2-pyrrolidone.

  To this solution, while cooling to 50 ° C. or lower with a water jacket, 4722.2 g of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was gradually added to advance the polymerization reaction. As a result, a viscous polyamic acid varnish containing polyamic acid and N-methyl-2-pyrrolidone which is a precursor of the non-thermoplastic polyimide resin was obtained. Thereafter, in order to improve the workability of the coating film, cooking was performed at 80 ° C. until the rotational viscosity of the varnish became 10 Pa · s.

[Preparation of thermosetting resin varnish]
(Formulation example 1)
Polyamideimide resin (KS9900F, manufactured by Hitachi Chemical Co., Ltd.) 35.93 kg (resin solid content: 33.4% by mass), HP7200 (trade name, manufactured by Dainippon Ink Co., Ltd.) which is an epoxy resin, (resin solid content: 50 Mass% methyl ethyl ketone solution), epoxy resin EPPN502H (trade name, manufactured by Nippon Kayaku Co., Ltd.) 2.0 kg (methyl ethyl ketone solution having a resin solid content of 50 mass%), and 1-cyanoethyl-2-ethyl-1-methylimidazole 8.0 g was blended and stirred for about 1 hour until they became uniform, and then allowed to stand at room temperature for 24 hours for defoaming to obtain a thermosetting resin varnish of Formulation Example 1.

(Formulation example 2)
Polyamideimide resin (KS9900B, manufactured by Hitachi Chemical Co., Ltd.) 22.44 kg (resin solid content: 31.2% by mass), EPPN502H (trade name, manufactured by Nippon Kayaku Co., Ltd.) 2.0 kg (resin solid content: 50 mass) % Methyl ethyl ketone solution), epoxy resin HP4032D (trade name, manufactured by Nippon Kayaku Co., Ltd.) 3.0 kg, epoxy resin NC3000 (product name, manufactured by Nippon Kayaku Co., Ltd.) 1.0 kg (resin solid content 50% by mass) Of methyl ethyl ketone solution) and 8.0 g of 1-cyanoethyl-2-ethyl-1-methylimidazole, and stirred for about 1 hour until they became homogeneous, and then allowed to stand at room temperature for 24 hours for defoaming. A thermosetting resin varnish of Formulation Example 2 was obtained.

(Formulation example 3)
Epoxy resin BREN-S (trade name, manufactured by Nippon Kayaku Co., Ltd.) 3.0 kg, curing agent FG-2000 (trade name, manufactured by Teijin Chemicals Ltd.) 1.81 kg, curing accelerator 1-cyanoethyl- After dissolving 10.0 g of 2-ethyl-1-methylimidazole in 6.0 kg of methyl isobutyl ketone, HTR-860-P3 (trade name, manufactured by Nagase ChemteX Corporation: 15% methyl ethyl ketone solution) which is an acrylic resin. 87 kg was further added and stirred for 1 hour to obtain the thermosetting resin varnish of Formulation Example 3.

[Production of double-sided copper foil-clad laminate (metal foil-clad laminate)]
(Examples 1 to 13)
First, said polyamic acid varnish was apply | coated on the roughening surface of copper foil using the coating machine (comma coater). Here, as a copper foil, “BHY-02B-T” (Examples 1 to 8 and 12 to 13, trade names manufactured by Nikko Materials), which is a rolled copper foil having a width of 540 mm and a thickness of 12 μm, which is roughened on one side, “ F0-WS-12 "(Example 9)," F2-WS-12 "(Example 10, above, trade name manufactured by Furukawa Circuit Foil), or" MT18SD-H3 "(Example 11, manufactured by Mitsui Kinzoku Co., Ltd.) Product name). At this time, the coating thickness of the polyamic acid varnish was such that the thickness of the non-thermoplastic polyimide layer formed from the polyamic acid varnish was as shown in Table 1 or 2, respectively.

  Next, the copper foil coated with the varnish is heat-treated at a maximum temperature of 400 ° C. and a residence time of 15 minutes using a continuous curing furnace to change the precursor polyamic acid into a non-thermoplastic polyimide resin. Thus, a non-thermoplastic polyimide layer was formed on the copper foil.

  Subsequently, on the non-thermoplastic polyimide layer formed on the copper foil, after applying any of the thermosetting resin varnishes of Formulation Examples 1 to 3 described above with a die coater, 100 to 140 ° C. in a drying furnace, The thermosetting resin layer was formed by drying for a residence time of 5 minutes. The type of thermosetting resin varnish used in each example and the thickness of the thermosetting resin layer obtained after drying were as shown in Table 1 or 2. Thereby, the various laminated bodies which have the structure where the non-thermoplastic polyimide resin layer and the thermosetting resin layer were laminated | stacked sequentially on copper foil were obtained.

  Then, for each of the examples, two of the above laminates were prepared, and the corresponding ones were stacked so that the glass cloth as the fiber base material was sandwiched between the thermosetting resin layers, and then the stacking direction Was pressed. Here, as a glass cloth which is a fiber base material, “WEX-1027” (Examples 1 to 11, thickness 19 μm), “WEX1015” (Example 12, thickness 15 μm) or “WEX-1037” (Example 13) , Thickness 29 μm). The press conditions were as shown in Table 1 or 2, respectively.

  Thus, Examples 1 to 13 each having a structure in which a non-thermoplastic polyimide resin layer and a copper foil are sequentially laminated on both surfaces of a base material layer in which a thermosetting resin layer and a glass cloth are substantially integrated and cured. A double-sided copper foil-clad laminate (metal foil-clad laminate) was obtained.

(Comparative Examples 1-5)
Except for changing the thickness of the non-thermoplastic polyimide layer formed of the polyamic acid varnish, the type and application thickness of the thermosetting resin varnish, and the press conditions as shown in Table 3, Examples In the same manner as in Example 1, double-sided copper foil-clad laminates of Comparative Examples 1 to 5 were produced.

(Comparative Example 6)
On the roughened surface of “BHY-02B-T” which is a rolled copper foil, the thermosetting resin varnish of Formulation Example 1 was applied so that the thickness after drying was 30 μm, and then 100 to 100 in a drying furnace. It dried at 140 degreeC and residence time 5 minutes, and obtained the laminated body which has a structure in which the thermosetting resin layer was formed on copper foil.

  Two of these laminates were prepared, and these were laminated so that a glass cloth (WEX-1027) as a fiber base material was sandwiched between thermosetting resin layers, and then pressed in the laminating direction. The pressing conditions were as shown in Table 3.

  Thus, a double-sided copper foil of Comparative Example 6 having a structure in which a thermosetting resin layer and a glass cloth are substantially integrated and cured, and a copper foil is provided on both surfaces of the base material layer, respectively. A tension laminate was obtained.

[Characteristic evaluation]
The following various evaluations were performed using the double-sided copper foil-clad laminates obtained in Examples 1 to 13 and Comparative Examples 1 to 6, respectively. The results obtained with each double-sided copper foil-clad laminate are shown in Tables 1-3.

  However, the double-sided copper foil-clad laminate obtained in Comparative Example 5 did not sufficiently impregnate the thermosetting resin into the glass cloth, resulting in a double-sided copper foil-clad laminate with an incomplete structure. Therefore, for the double-sided copper foil-clad laminate of Comparative Example 5, all the following characteristics evaluations could not be performed.

(Measurement of thickness difference of non-thermoplastic polyimide resin layer)
The cross section along the laminating direction of the double-sided copper foil-clad laminate was observed with a microscope. Based on this, the distance between the average line of the irregularities at the interface between the non-thermoplastic polyimide resin layer and the base material layer and the average line of the irregularities at the interface between the non-thermoplastic polyimide resin layer and the copper foil is obtained, and this Was the thickness of the non-thermoplastic polyimide resin layer. And the absolute value of the difference of the thickness of the two non-thermoplastic polyimide resin layers provided on both surfaces of the base material layer was calculated. In addition, about the double-sided copper foil clad laminated board obtained by the comparative example 6, since the non-thermoplastic polyimide resin layer was not provided, this measurement was not performed.

(Evaluation of solder heat resistance)
A 50 mm × 50 mm test piece was cut out from the double-sided copper foil-clad laminate, and the test piece was floated on a solder bath at 288 ° C., and the time until blistering was measured. About the double-sided copper foil-clad laminate of each Example or Comparative Example, the same measurement was performed using 5 test pieces, and the average time of the results obtained with 5 test pieces was determined. The solder heat resistance was evaluated. The longer the average time, the better the solder heat resistance. However, the upper limit of the test time was 300 seconds.

(Measurement of sled)
A double-sided copper foil-clad laminate was cut into a width of 10 mm and a length of 200 mm to obtain a measurement sample, and the measurement sample was measured for the height of a portion 100 mm from the end in the longitudinal direction using a warp gauge. The larger this value, the greater the warpage.

(Evaluation of bendability)
The copper of the double-sided copper-clad laminate was removed by etching, and this was used as a test substrate. The test substrate was bent 180 degrees with a pin gauge (0.1 mmφ) sandwiched between them, and the finger was moved along the bent portion while strongly pressing with a finger, and then the test substrate was returned to its original position. The test substrate after this operation was observed, and whether or not cracks or breaks occurred at the bent portion was visually observed to evaluate the bendability. The case where no cracks or breakage was observed was judged as “good”, and other cases were designated as “cracked” or “breakage”.

(Evaluation of warpage and curl of composite substrate)
First, copper of the double-sided copper foil-clad laminate was removed by etching. The composite substrate thus obtained was visually observed for the presence or absence of curling and waving. About the composite base material which was judged to be flat by visual observation, the warpage was further measured by a warpage gauge, and those that could be confirmed that no warpage occurred were described as “None” in Tables 1 to 3.

(Measurement of thermal expansion coefficient of composite substrate)
First, the copper foil of the double-sided copper foil-clad laminate was removed by etching. The composite base material obtained in this manner was cut out into 25 mm × 4 mm and used as a measurement sample. The thermal expansion coefficients of these measurement samples were determined by measuring a range of 20 to 300 ° C. in a tensile mode at a temperature rising rate of 10 ° C./min using a thermomechanical analyzer manufactured by Texas Instruments.

(Evaluation of tear resistance of composite substrate)
First, the copper foil of the double-sided copper foil-clad laminate was removed by etching. The composite base material thus obtained was cut into a width of 10 mm and a length of 100 mm, and a 1 mm cut was made in a direction perpendicular to the longitudinal direction at a position 50 mm from the end in the longitudinal direction. did. While fixing one end in the longitudinal direction of the sample for measurement and applying a load of 500 g to the other end, twisting 180 degrees left and right at this rate is performed at a speed of 60 times / minute, and the number of times until the sample breaks is measured. did. However, the upper limit of the number of measurements was 300. It means that it is excellent in tearing resistance, so that this frequency | count is large.

(Measurement of dielectric strength of composite substrate)
A test piece of 100 mm × 100 mm was cut out from the double-sided copper foil-clad laminate, and the copper foil on one side of the test piece was etched into a 50 mmφ circular shape, and then at a rate of 100 V / sec between the opposing copper foils. While increasing the voltage, a voltage was applied until dielectric breakdown occurred. And the voltage when insulation broke was made into the withstand voltage of a composite base material.

  As shown in Tables 1 to 3, the double-sided copper foil-clad laminates obtained in Examples 1 to 13 are all excellent in solder heat resistance, have no warpage, and further have these. It was confirmed that the composite substrate also had good bendability, no warpage or curling, and good tear resistance and dielectric strength. On the other hand, the double-sided copper foil-clad laminates obtained in Comparative Examples 1, 2, 3, 4 and 6 are warped in the double-sided copper foil-clad laminates and composite substrates, or the bending properties are not sufficient. In addition, it did not have all the characteristics of the double-sided copper foil-clad laminates of the examples, such as poor tear resistance.

  DESCRIPTION OF SYMBOLS 10,20 ... Laminated body, 11, 21 ... Metal foil, 12, 22 ... Non-thermoplastic polyimide resin layer, 13, 23 ... Thermosetting resin layer, 25 ... Base material layer, 30 ... Fiber base material, 50 ... Composite Base material, 100 ... metal foil-clad laminate.

Claims (7)

A first metal foil, a first non-thermoplastic polyimide resin layer, a substrate layer composed of a thermosetting resin and a fiber substrate having a thickness of 25 μm or less, and a second non-thermoplastic polyimide resin layer And a second metal foil in this order,
The thickness of the base material layer is 100 μm or less,
The thickness of the first non-thermoplastic polyimide resin layer and the second non-thermoplastic polyimide resin layer is 1 μm or more and 10 μm or less, and
The absolute value of the difference between the thickness of the first non-thermoplastic polyimide resin layer and the thickness of the second non-thermoplastic polyimide resin layer is less than 3 μm.
A metal foil-clad laminate.   The metal foil-clad laminate according to claim 1, wherein the fiber base material is a glass cloth.   The non-thermoplastic polyimide resin constituting the first non-thermoplastic polyimide resin layer and the second non-thermoplastic polyimide resin layer is an anhydride of at least one of biphenyltetracarboxylic acid anhydride and pyromellitic acid anhydride. A product obtained by reacting a product with at least one diamine selected from the group consisting of 4,4'-diaminodiphenyl ether, p-phenylenediamine and m-phenylenediamine. 3. A metal foil-clad laminate according to 1 or 2.   The thermosetting resin contains at least one resin selected from the group consisting of a resin having a glycidyl group, a resin having an amide group, and an acrylic resin. Metal foil-clad laminate as described in 1.   A print obtained by processing the first metal foil and / or the second metal foil in the metal foil-clad laminate according to any one of claims 1 to 4 into a circuit. Wiring board.   A first laminate including a first metal foil, a first non-thermoplastic polyimide resin layer, and a first thermosetting resin layer in this order, a second metal foil, and a second non-thermoplastic polyimide resin layer And the second laminated body including the second thermosetting resin layer in this order, the fiber base material with the first thermosetting resin layer and the second thermosetting resin layer facing each other. A method for producing a metal foil-clad laminate, comprising the steps of stacking, heating and pressurizing.   The metal foil according to claim 6, wherein an absolute value of a difference between a thickness of the first non-thermoplastic polyimide resin layer and a thickness of the second non-thermoplastic polyimide resin layer is less than 3 μm. A method for producing a laminated laminate.

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