TW201504037A - Metal foil laminate - Google Patents

Abstract

To attain simultaneously the prevention of a tip from sinking into a substrate film layer in bonding the tip to metal wiring (namely mountability) and properties which have a trade-off relationship therewith, namely, flex resistance, folding endurance, pliability, and reduction in spring back which is seen as a problem in mounting a circuit board in a bent state or the like. A metal foil laminate composed of a metal foil and a substrate film which is made of a heat-resistant resin composition that comprises a polyimide-based resin crosslinked with an epoxy resin and which is laminated on at least one surface of the metal foil, characterized by satisfying the requirements (a) and (b): (a) when the total amount of the polyimide-based resin and the epoxy resin is taken as 100 mass%, the amount of the epoxy resin is 0.1 to 10 mass%; and (b) the insoluble matter rate of a base film which has been prepared by removing the metal foil from the metal foil laminate is 40% or more as determined by adding N-methyl-2-pyrrolidone to the base film in such an amount as to adjust the base film concentration to 0.5 mass% and heating the resulting mixture at 100 DEG C for 2 hours.

Description

Metal foil laminate

The present invention relates to a metal foil laminate obtained by laminating a polyimide resin on at least one side of a metal foil, and a flexible printed substrate using the metal foil laminate. In particular, it is an ideal metal foil laminate which is a substrate for a chip-on-film (hereinafter referred to as COF) which is an electronic component such as an IC (integrated circuit) or an LSL (large-scale integrated circuit).

In general, polyimine-based resins are widely used as insulating materials for electric and electronic equipment, such as heat resistance, insulation, and chemical resistance. In particular, it is widely used as a wiring board material for various electronic devices and a substrate material for packaging, and is, for example, a component package substrate for a display device such as a liquid crystal display device, a plasma display, or an organic EL display. A wiring board, an operation switch unit substrate, and the like are connected between substrates such as smart phones, tablet terminals, digital cameras, and portable game machines.

In recent years, in the use of liquid crystal display devices, smart phones, and tablet terminals, the demand for miniaturization, weight reduction, and thinness of the device has progressed, and the demand for flexible printed circuit boards for directly loading (packaging) electronic components such as ICs and LSIs has been demanded. Soaring. Moreover, in the packaging method of such electronic components, the COF method capable of performing higher density packaging at a smaller pitch is more often used than the conventional tape carrier package (hereinafter referred to as TCP). The COF substrate is a composite component in which a semiconductor wafer such as an IC or an LSI is directly mounted on a film-shaped wiring board. In many cases, it is connected to a large-sized rigid wiring board, a liquid crystal display device, or an organic EL display, and the like. .

The COF substrate is produced by a metal foil laminate (two-layer flexible metal foil laminate) having a two-layer structure in which a metal foil such as a copper foil is laminated on a heat-resistant resin film such as polyimide. For example, a fine pattern is formed on the copper foil surface of the two-layer flexible metal foil laminate by a photolithography method or the like, and plating such as tin is applied to a necessary position, and a solder resist is applied. The package of the semiconductor wafer is to apply a plating COF wire pattern to the connection terminals (bumps) of the wafer with ACF/ACP (joining method using anisotropic conductive film/paste), NCF/NCP (using non-conductive) Bonding method of film/paste), ultrasonic bonding, Au-Au bonding, Au-Sn bonding, etc., but in particular considering the connection reliability, it is widely used in Au-Au bonding at a temperature of 400 ° C or higher. , Au-Sn joint. After that, it is connected to another rigid wiring board or the like, and is attached to a panel or the like to be connected to the final product. However, in many cases, it is bent into a U-shape and a U-shape and incorporated.

Such COF substrates are subject to various problems due to the advancement of fine patterning, the increase in density and density of IC packaging technology, and the miniaturization, weight reduction, and thinness of electronic devices. For example, there is a problem that "the bump of the wafer is hidden" due to the deformation of the polyimide film at the wafer package temperature. Or, with the fine patterning, there is a problem that the folding endurance is lowered. In addition, in order to reduce the size, weight, and thickness of the electronic device, when it is incorporated into the final product, it is mounted in a more compact shape such as a U-shape or a U-shape, and as a result, a spring back of the substrate material occurs ( The force to return to the original state is increased, and trouble occurs in the joint portion with the final product such as the panel. Therefore, high properties are required for the substrate material.

A two-layer flexible metal foil laminate which is a raw material of a COF substrate, and has the following types: a) a laminated type in which a metal foil and a polyimide film are laminated with a thermoplastic polyimide adhesive (Patent Document) 1), b) a casting type in which a polyimide resin is cast and laminated on a metal foil (Patent Document 2), c) a metal such as Cr is directly sputtered on the polyimide film to be vapor-deposited, and then A metallization type in which copper is electrolessly and/or electrolytically plated (Patent Document 3). In general, in the case of a metallized two-layer flexible metal foil laminate, there is no problem that bumps are hidden at the package temperature, but the adhesion and the folding resistance are poor, and in particular, the fine pattern may be easily broken. problem. Moreover, the bounce is large, and when the COF substrate is bent and mounted, the lead terminals connected to the external circuit often have troubles such as fragile lines. On the other hand, in the case of a cast type or a laminated two-layer flexible metal foil laminate, the adhesiveness or the folding endurance property can be appropriately exhibited, but there is a problem that the bumps are hidden during the semiconductor wafer package, and The folding resistance in the case of a fine pattern is also unsatisfactory. Moreover, the problem of bounceback has not been resolved.

As described above, the characteristics of the COF substrate obtained by the method of manufacturing the two-layer flexible metal foil laminate have advantages and disadvantages, and it has not yet fully satisfactorily satisfies, for example, bump occlusion in the semiconductor chip package encountered in recent years, accompanied by fine patterning. A two-layer flexible metal foil laminate having various problems such as a reduction in folding endurance and a problem of rebound during assembly.

For example, Patent Document 4 and Patent Document 5 disclose a two-layer flexible metal foil laminate in which a bump is hidden by a casting method, but the problem of folding end resistance and rebound is not solved. In Patent Document 6, although it is considered to improve the folding endurance by the layering method, the improvement of the bumps is not enough. Patent Document 7 and Patent Document 8 discuss the improvement of the springback by the metallization method, the improvement of the adhesion, and the like, but they are still insufficient, and there is a problem that the folding resistance is poor.

On the other hand, in order to improve the heat resistance of a polyimide resin, a polyimide, and a polyimide resin, a crosslinking agent, such as an epoxy resin, is mix|blended with these resin, and it is used as an adhesive agent. . However, a resin having a high glass transition point such as a polyimide resin has a poor molecular mobility, and the crosslinking reaction must depend on the molecular motion of the blend, and a large amount of a crosslinking agent must be blended. Or, most of them must be introduced into a functional group as a crosslinking point in the side chain of the resin, or a combination of a plurality of polyfunctional isocyanates, polyfunctional phenols, phenoxy resins, etc., and in the crosslinked structure of the blends. And/or chemically introduced a polymer such as a polyimide resin. Therefore, even if a certain degree of heat resistance can be imparted, it is difficult to impart a package property of 400° C. or more, and mechanical properties such as folding resistance and bending resistance are also lowered, so that packageability, folding resistance, bending resistance, and low elasticity are satisfied. Back to all features is difficult.

For example, Patent Document 9 discloses that a large amount of an epoxy resin is blended in a polyamidoximine resin, and Patent Document 10 discloses an example in which a crosslinkable composition is obtained by further using a phenoxy resin in combination. In addition, in Patent Document 11 and Patent Document 12, it is attempted to introduce a functional group which becomes a crosslinking point into a polyimide resin, and Patent Document 13, Patent Document 14, Patent Document 15, and Patent Document 16 attempt to further blend into excessive crosslinking. Epoxy or phenoxy resin of the binder is used for efficient crosslinking. However, it is difficult to obtain a tough molded body from any of the resin compositions, and it is currently difficult to achieve both bending resistance, folding endurance, flexibility, and low springback in a relationship with encapsulation. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Laid-Open Patent Publication No. 2000-150552 (Patent Document 3) Japanese Laid-Open Patent Publication No. 2012-186307 (Patent Document 4) JP-A-2006-130747 [Patent Document 5] Japanese Patent Laid-Open Publication No. JP-A-2006-006200 (Patent Document 7) Japanese Laid-Open Patent Publication No. 2003-006200 (Patent Document 7) Japanese Patent Laid-Open Publication No. Hei. No. 2011-35930 (Patent Document 11) Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. Japanese Special Open 2009-147116

(The subject to be solved by the invention)

An object of the present invention is to solve the above problems, and it is possible to inexpensively manufacture a metal foil laminate for a flexible printed circuit board such as a COF substrate, and a flexible printed circuit board. In other words, the metal foil laminate suitable for use as a substrate for COF can achieve both high-quality characteristics such as maintaining warpage, dimensional accuracy, and adhesion of the substrate, and bonding the wafer to the metal wiring. When the wafer is prevented from being hidden from the base film layer (that is, the package property), and the packageability is changed, the bending resistance, the folding endurance, the flexibility, and the substrate bending and packaging are regarded as problems. Such as the reduction (that is, low rebound). (method of solving the problem)

As a result of intensive studies, the inventors of the present invention have found that a resin composition can be obtained by blending a small amount of an epoxy resin in a polyimine-based resin which is soluble in a solvent and excellent in heat resistance, thereby forming a crosslinked structure. The object of the invention is achieved. Further, the epoxy resin used in the present invention can function as a crosslinking agent.

In the crosslinked structure of the present invention, by adding an epoxy resin to a polyimine-based resin having various properties and using the reaction conditions described later, it is possible to form a crosslink with only the functional group of the resin terminal of the polyimine-based resin. The structure maintains the conventional characteristics while maintaining low warpage, dimensional accuracy, adhesion, and the like while satisfying encapsulation, bending resistance, folding resistance, flexibility, and low rebound. Specifically, it has been found that the original bending resistance, folding resistance, flexibility, and low elasticity of the resin are maintained by making the crosslinking point only the end of the resin having the composition, molecular weight, acid value, and logarithmic viscosity. A structure that regains mechanical properties and is resistant to encapsulation.

That is, the present invention is the following flexible metal foil laminate or flexible printed substrate.

[1] A metal foil laminate obtained by laminating a heat-resistant resin composition containing a polyimine-based resin obtained by crosslinking an epoxy resin on at least one side of a metal foil. The metal foil laminate of the metal foil satisfies the following (a) and (b); (a) when the total amount of the polyimide resin and the epoxy resin is 100% by mass, the blending amount of the epoxy resin (b) 0.1% by mass or more and 10% by mass or less; (b) adding N-methyl-2-pyrrolidone to the base film obtained by removing the metal foil from the metal foil laminate, and setting the concentration of the base film to 0.5% by mass, The insolubility after heat treatment at 100 ° C for 2 hours was 40% or more. [2] The metal foil laminate according to [1] further satisfies the following (c) and/or (d); (c) the logarithmic viscosity of the polyamidene resin before crosslinking, in N-methyl- 2-pyrrolidone (polymer concentration: 0.5 g/dl) and 0.40 dl/g or more and 3.50 dl/g or less under the measurement conditions of 30 ° C; (d) Polycondensation of uncrosslinked portion after crosslinking by epoxy resin The logarithmic viscosity of the imine resin is 0.40 dl/g or more and 3.50 dl/g or less in N-methyl-2-pyrrolidone (polymer concentration: 0.5 g/dl) and under the measurement conditions of 30 °C. [3] The metal foil laminate of [1] or [2] further satisfies the following (e) and/or (f); (e) the number average molecular weight of the polyamidene resin before crosslinking is 10,000. Above 200000. (f) The polyamidimide-based resin having an uncrosslinked portion after crosslinking by an epoxy resin has a number average molecular weight of 10,000 or more and 200,000 or less. [4] The metal foil laminate according to any one of [1] to [3], which further satisfies the following (g) and/or (h); (g) the acid of the polyamidene resin before crosslinking The valence is 5 eq/ton or more and 1000 eq/ton or less; (h) The polyvalent imide resin having an uncrosslinked portion after crosslinking by an epoxy resin has an acid value of 5 eq/ton or more and 1000 eq/ton or less. [5] The metal foil laminate according to any one of [1] to [4], which further satisfies the following (i); (i) when all the solid components in the heat resistant resin composition are 100% by mass, The total blending amount of the quinoneimide resin and the epoxy resin is 30% by mass or more. [6] The metal foil laminate according to any one of [1] to [5], which further satisfies the following (j); (j) the polyamidene resin is a polyamidoximine resin, polyamine The structural unit of the quinone imine resin contains the repeating structural unit represented by the formula (1): 5 mol% or more and 99 mol% or less; The metal foil laminate according to any one of [1] to [6], further satisfying the following (k); (k) the epoxy resin is a phenol novolak of the following general formula (2) Glycidyl ether General formula (2) [n is an integer of 1 to 20]. [8] A flexible printed circuit board comprising the metal foil laminate according to any one of [1] to [7]. [9] The flexible printed circuit board of [8] has a value of more than 190 times in accordance with the folding test of JIS C 5016. [10] The flexible printed circuit board of [8] or [9], wherein the Gurley has a softness of less than 800 mg. (Effect of the invention)

The flexible printed circuit board obtained by the metal foil laminate of the present invention is prevented from being hidden from the base film layer when the wafer is bonded to the metal wiring, that is, the package is excellent, or the substrate is bent and packaged. It is suitable as a substrate for a chip-on-film (hereinafter referred to as COF) because it is excellent in bending resistance, folding resistance, and flexibility (panel assembly property). Further, since the resin composition used in the present invention is soluble in an organic solvent, it is not required to be subjected to high-temperature heat treatment, and can be produced inexpensively. Of course, the quality required for the COF substrate, such as low warpage, dimensional accuracy, and adhesion, is maintained at a high level. The high-performance flexible substrate can be manufactured inexpensively, so that industrial benefits are large.

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

<Polyimide-based resin> The metal foil laminate of the present invention is a laminate of the base film and the metal foil in which a base film containing a heat-resistant resin composition is laminated on at least one side of the metal foil. body. The heat resistant resin composition is preferably a resin functional end group of a polyimine-based resin which is preferably crosslinked with an epoxy resin.

When the polyimine-based resin and the metal foil have the same thermal expansion coefficient and are excellent in heat resistance, substantially every resin can be used, and preferably a polyimide resin and/or a polyamide amide resin. It is preferably a polyimine resin which is soluble in an organic solvent and/or a polyamidoximine resin which is soluble in an organic solvent. The polyimine-based resin is obtained by a polycondensation reaction of an acid component and an amine component (or an isocyanate component corresponding thereto), and may be, for example, a diisocyanate method, a hydrazine chloride method, a low-temperature solution polymerization method, or a room temperature solution polymerization method. It is manufactured by a conventionally known method. Industrially, the obtained polymerization solution can be directly used as a diisocyanate method which is used as a casting varnish to be described later.

Further, in the present invention, "soluble in an organic solvent" means selected from N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamidine. a group consisting of an amine, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, cyclobutyl hydrazine, dimethyl hydrazine, γ-butyrolactone, cyclohexanone, and cyclopentanone In any of the single solvent or the mixed organic solvent containing at least one of 20% by mass or more, the resin is dissolved in an amount of 10% by mass or more, preferably 15% by mass or more, and more preferably 20% by mass or more. It is preferably dissolved in 10% by mass or more, preferably 15% by mass or more, and more preferably 20% by mass or more in N-methyl-2-pyrrolidone (purity: 99.9%). Further, in the case where the resin was solid, the resin powder of 80 mesh was used in a 200 ml beaker, and it was used as it was in the case of liquid. The resin powder was added to the above organic solvent to obtain 10, 15, and 20% by mass, and the solution was stably stirred at 25 ° C for 24 hours, and the solution was allowed to stand at 25 ° C for 24 hours to visually observe no gelation, unevenness, and white turbidity. If any of the precipitates is present, it is determined that it has dissolved.

Further, the polyimine-based resin which can be used in the present invention is not particularly limited, and a polyimide-based resin having a functional group only at the resin terminal is preferred. If the functional group is only at the end of the resin of the polyimine-based resin, only the functional group present at the terminal end reacts with the epoxypropyl group of the epoxy resin. When a functional group is present in a portion other than the resin terminal, a crosslinking reaction with the epoxy resin occurs, and the original mechanical properties such as bending resistance, folding resistance, flexibility, and low rebound are lowered, which is not preferable. The functional group at the terminal of the resin of the polyimine-based resin is preferably a carboxyl group, an acid anhydride group, an isocyanate group or an amine group, and a carboxyl group or an acid anhydride group is particularly preferable.

Hereinafter, the polyimine resin and the polyamidoximine resin which can be used in the present invention will be described.

<Acid Component of Polyimine] The polyimine resin which can be used in the present invention is not particularly limited, and is preferably a polyimine resin which is soluble in an organic solvent. The acid component used in the polyimine resin which can be used in the present invention can be used alone as pyromellitic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, 3,3', 4,4'- Biphenyltetracarboxylic acid, 3,3',4,4' diphenylphosphonium tetracarboxylic acid, 3,3',4,4'-diphenyl ether tetracarboxylic acid, -2,3,6,7-tetracarboxylic acid, -1,2,4,5-tetracarboxylic acid, A monomer such as a monoanhydride, a dianhydride or an esterified product such as a 1,4,5,8-tetracarboxylic acid or a mixture of two or more kinds thereof.

<Amine component of polyimine resin> The amine component (or the isocyanate component corresponding thereto) used in the polyimine resin which can be used in the present invention, p-phenylenediamine, m-phenylenediamine, 2, 4 can be used alone. -diaminotoluene, 2,5-diaminotoluene, 2,4-diaminoxylene, p-xylenediamine, m-xylenediamine, 2,4-diaminopurine, 1,4- Diamine, 1,5- Diamine, 2,6- Diamine, 2,7- Diamine, benzidine, 3,3'-dihydroxybenzidine, 3,3'-dimethoxybenzidine, 3,3'-dimethyl-4,4'-diaminobiphenyl (neighbor) Toluidine), 3,3'-diethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-di Ethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-diethoxy-4,4'- Diaminobiphenyl, 2,2'-bis(trifluoromethyl)benzidine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4' -diaminodiphenyl ether, 2,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenylanthracene, 3,3'- Diaminodiphenylphosphonium, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 4,4'-diaminodiphenyl sulfide, 3,3' -diaminodiphenyl sulfide, 4,4'-diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 4,4'-methylenebis(2-methyl Aniline), 4,4'-methylenebis(2-ethylaniline), 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-methylenebis ( 2,6-diethylaniline), 4,4'-diaminophenylbenzophenone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminobenzene) Oxy)benzene, 1,3-bis(3-amine Phenoxy)benzene, diamine-linked triphenylene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(3-aminophenoxy)phenyl)anthracene, Bis(4-(4-aminophenoxy)phenyl)anthracene, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 2,2-bis(4-(4) A monomer such as -aminophenoxy)phenyl)hexafluoropropane or 2,2-bis(4-aminophenyl)hexafluoropropane or a mixture of two or more kinds thereof.

<Acid component of polyamidoximine resin> The polyamidoximine resin which can be used in the present invention is not particularly limited, and is preferably a polyamidoximine resin which is soluble in an organic solvent. As the acid component used in the polyamidoximine resin which can be used in the present invention, trimellitic anhydride, diphenyl ether-3,4,4'-tricarboxylic anhydride, diphenylphosphonium-3, 4 can be used alone. 4'-tricarboxylic anhydride, benzophenone-3,4,4'-tricarboxylic anhydride, A monomer of a tricarboxylic anhydride such as -1,2,5-tricarboxylic anhydride or a mixture of two or more kinds.

Further, in addition to the tricarboxylic anhydride, terephthalic acid, isophthalic acid, diphenyl ether dicarboxylic acid, diphenylphosphonium dicarboxylic acid, benzophenone dicarboxylic acid, biphenyl dicarboxylic acid, or the like may be used alone. The dicarboxylic acid is a compound exemplified as the acid component of the polyimine resin or a mixture of two or more kinds. Alternatively, a compound exemplified as the acid component of the above dicarboxylic acid and polyimine resin may be used in combination.

<Amine component of polyamidoximine resin> The amine component (or the isocyanate component corresponding thereto) used in the polyamidoximine resin which can be used in the present invention can be exemplified as the amine component of the polyimide resin Compound.

Further, as long as the object of the present invention is not impaired, the acid component and the amine component shown below may be used in addition to the above-exemplified acid component and amine component.

<Acid component which can be copolymerized> As the acid component, an aliphatic dicarboxylic acid such as adipic acid, sebacic acid, sebacic acid or dodecanoic acid, or butane-1,2,4-tricarboxylic acid can be used alone. An aliphatic tetracarboxylic acid such as an acid anhydride, a dianhydride, an esterified product, a butane-1,2,3,4-tetracarboxylic acid, a cyclopentane-1,2,3,4-tetracarboxylic acid or the like An carboxylic acid anhydride, a dianhydride, an esterified product, an alicyclic dicarboxylic acid such as cyclohexane-4,4'-dicarboxylic acid, cyclohexanetricarboxylic acid, dicyclohexylether-3,3',4 An acid anhydride, an esterified product of an aliphatic tetracarboxylic acid such as tricarboxylic acid, dicyclohexylindole-3,4,4'-tricarboxylic acid or dicyclohexylmethane-3,4,4'-tricarboxylic acid An alicyclic tetracarboxylic acid monoanhydride such as cyclopentane-1,2,3,4-tetracarboxylic acid, a dianhydride, an esterified product or the like, or used in the form of a mixture. Further, an acid component or a mixture exemplified as the acid component of the polyimide resin may be used alone.

<Copolymerizable amine component> As the amine component, trans-1,4-diaminocyclohexane, cis-1,4-diaminocyclohexane, 1,4-diamine group can be used alone. Cyclohexane (trans/cis mixture), 1,3-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine) (trans, cis, trans/cis Mixture), isophoronediamine, 1,4-cyclohexanebis(methylamine), 2,5-bis(aminomethyl)bicyclo[2.2.1]heptane, 2,6-bis ( Aminomethyl)bicyclo[2.2.1]heptane, 3,8-bis(aminomethyl)tricyclo[5.2.1.0]decane, 1,3-diamine, adamantane, 4,4'- Methylene bis(2-methylcyclohexylamine), 4,4'-methylenebis(2-ethylcyclohexylamine), 4,4'-methylenebis(2,6-dimethyl Cyclohexylamine), 4,4'-methylenebis(2,6-diethylcyclohexylamine), 2,2-bis{4-(4-aminocyclohexylether)cyclohexyl}propane, 2 , an aliphatic alicyclic diamine such as 2-bis{4-(4-aminocyclohexylether)cyclohexyl}hexafluoropropane, an aliphatic diamine such as tetramethylenediamine or hexamethylenediamine, or The diisocyanate corresponding to these is used in the form of a mixture of two or more kinds.

The polyimine-based resin which can be used in the present invention is used for the detachability (encapsulation property) of the wafer to the base film layer when the wafer is bonded to the metal wiring, or the resilience, bending resistance, and resistance of the substrate when the substrate is bent and packaged. In terms of balance of flexibility, flexibility, and manufacturing cost, it is preferably an aromatic polyimine resin and/or an aromatic polyamidimide resin which is soluble in an organic solvent, and more preferably in a polyfluorene. The structural unit of the amine imide resin contains an aromatic polyamidoximine resin of a repeating unit represented by the following formula (1).

【化1】 Formula 1)

The repeating unit represented by the formula (1) is preferably 5 mol% or more and 99 mol% or less, more preferably 30 mol% or more and 95 mol% or less, still more preferably 50 mol% or more and 80 mol%. The following polyamidoximine resins are preferred. When the amount is less than 5 mol%, there is a problem in encapsulation, and if it exceeds 99 mol%, the solubility in an organic solvent may be insufficient, and workability in a solution form may be difficult.

As an ideal structural unit, in terms of acid composition, trimellitic anhydride (TMA), 3,3', 4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 3, 3', 4 are used. , 4'-biphenyltetracarboxylic dianhydride (BPDA), for the amine component, o-tolidine (or diisocyanate) is used, and the composition ratio of the acid component (Mohr ratio) is TMA/BTDA/BPDA= Polyacrylamide quinone resin of 80~50/5~20/15~45 is preferred. In the case of the isocyanate component (or the corresponding amine component thereof), the ortho-toluidine diisocyanate has a composition ratio of all the isocyanate component (or the corresponding amine component thereof) of 50 mol% or more. An amine resin is preferred. Of course, these polyamidoximine resins may be used by mixing two or more kinds of resins which are separately polymerized.

<Polymerization of Polyimine Ion Resin> The polyimide-based resin is obtained by a polycondensation reaction of an acid component and an amine component (or an isocyanate component corresponding thereto), and can be, for example, a diisocyanate method, a hydrazine method, or a low temperature. It is produced by a conventionally known method such as a solution polymerization method or a room temperature solution polymerization method. It is preferred to use a diisocyanate method in which a polymer is obtained by a decarboxylation reaction and the obtained polymerization solution is directly used as a varnish for casting described later.

In the case of the diisocyanate method, the polyisocyanate component corresponding to the above-mentioned acid component and the amine component is subjected to polycondensation at an average chemical amount in an organic solvent at 100 to 200 ° C to obtain a polyfluorene used in the present invention. Imine resin. a polymerization solvent such as N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, Tetramethylurea, cyclobutyl hydrazine, dimethyl hydrazine, γ-butyrolactone, cyclohexanone, cyclopentanone, etc., preferably N-methyl-2-pyrrolidone, N,N-dimethyl B Indoleamine, 1,3-dimethyl-2-imidazolidinone. When these solvents are used as a polymerization solvent, they can be used as a solution for producing a metal-clad laminate to be described later. Further, some of these may be replaced by a hydrocarbon-based organic solvent such as toluene or xylene, an ether-based organic solvent such as diglyme, triglyme or tetrahydrofuran, or a ketone system such as methyl ethyl ketone or methyl isobutyl ketone. Organic solvents.

<Logarithmic viscosity of polyimide-based resin> The logarithmic viscosity of the polyimine-based resin before crosslinking by epoxy resin of the present invention is in N-methyl-2-pyrrolidone (polymer concentration: 0.5 g/dl) The logarithmic viscosity at 30 ° C is preferably 0.40 dl / g or more and 3.50 dl / g or less, preferably 0.80 dl / g or more and 3.50 dl / g or less, more preferably 1.00 dl / g or more and 3.50 dl / g or less, More preferably, it is 1.30 dl / g or more and 3.50 dl / g or less. If the logarithmic viscosity is less than 0.40 dl/g, mechanical properties such as bending resistance and folding resistance of the metal foil laminate and the flexible printed circuit board are insufficient. Moreover, when it exceeds 3.50 dl / g, the viscosity of the solution becomes high, and the molding process at the time of processing into a metal foil laminated body may become difficult. Moreover, the encapsulation property (the depression of the base film layer at the wafer package temperature) tends to deteriorate.

<Measurement of Logarithmic Viscosity> The logarithmic viscosity of the polyimine-based resin before crosslinking is determined by reprecipitating and refining a solution containing a polyimine-based resin before crosslinking in a large amount of acetone. Powdered polymer sample. The powder sample was dissolved in N-methyl-2-pyrrolidone to a polymer concentration of 0.5 g/dl, and the solution viscosity and solvent viscosity of the solution were measured at 30 ° C using a UBBELOHDE type viscosity tube. The logarithmic viscosity value is calculated according to the following formula. Logarithmic viscosity (dl/g)=[ln(V1/V2)]/V3 {In the above formula, V1 represents the viscosity of the solution measured by the UBBELOHDE type viscosity tube, and V2 represents the viscosity of the solvent measured by the UBBELOHDE type viscosity tube, but V1 and V2 were determined from the time when the polymer solution and the solvent (N-methyl-2-pyrrolidone) passed through the capillary of the viscosity tube. Further, V3 is a polymer concentration (g/dl). } or the varnish obtained after polymerization can also be used as a test sample. In this case, the varnish concentration was converted into a solid component, and the measurement sample solution was adjusted so that the polymer concentration became 0.5 g/dl. Further, the logarithmic viscosity of the polyfluorene-based resin which is not crosslinked by the epoxy resin can be extracted by using the polyunium-imide resin which has been extracted and uncrosslinked by the measurement of the insoluble ratio described later. Liquid to determine. It is preferred to use a powdery polymer sample prepared by reprecipitating and refining the extract with a large amount of acetone. Here, the polyfluorene-based resin having no cross-linking portion is mostly a polyimide-based resin which is not reacted with an epoxy resin in the case of the present application, but also includes a part even if it has reacted with an epoxy resin. But it is not completely part of the network structure (not insoluble).

The logarithmic viscosity of the polyfluorene-based resin of the uncrosslinked portion after crosslinking of the epoxy resin of the present invention, in N-methyl-2-pyrrolidone (polymer concentration: 0.5 g/dl), logarithm of 30 ° C The viscosity is preferably 0.40 dl/g or more and 3.50 dl/g or less, preferably 0.80 dl/g or more and 3.50 dl/g or less, more preferably 1.00 dl/g or more and 3.50 dl/g or less, and still more preferably 1.30 dl/g. g or more is 3.50 dl/g or less. If the logarithmic viscosity is less than 0.40 dl/g, mechanical properties such as bending resistance and folding resistance of the metal foil laminate and the flexible printed circuit board are insufficient. Moreover, when it exceeds 3.50 dl / g, the viscosity of the solution is improved, and molding processing at the time of processing into a metal foil laminated body may become difficult. Moreover, the encapsulation property (the depression of the base film layer at the wafer package temperature) tends to deteriorate.

<Quantum average molecular weight of the polyimine-based resin> The number average molecular weight of the polyimide-based resin before crosslinking of the epoxy resin of the present invention is preferably a molecular weight equivalent to 10,000 or more and 200,000 or less. It is 21,000 or more and 180,000 or less, and more preferably 47,000 or more and 160,000 or less. If the number average molecular weight is less than 10,000, mechanical properties such as bending resistance and folding resistance of the metal foil laminate and the flexible printed circuit board may be insufficient. Moreover, when it exceeds 200,000, the viscosity of a solution will raise, and the shaping|molding process at the time of processing of a metal foil laminated body may become difficult. Moreover, the encapsulation property (the depression of the base film layer at the wafer package temperature) tends to deteriorate.

<Measurement of Average Molecular Weight> The measurement of the molecular weight was carried out by a GPC method using a calibration curve prepared from a standard material under the following conditions. Mobile phase: N-methyl-2-pyrrolidone detector with 0.1% by mass of lithium bromide: Refractometer (made by Showa Denko Co., Ltd., SE-51) Standard material: Standard polystyrene of the following molecular weight (1) 6770000 (2)2870000 (3)1260000 (4)355000 (5)102000 (6)43900 (7)9500 (8)5400 (9)2800 Also, the pipe string will be shodex AD800P, shodex AD805/S, shodex AD804/S , shodex AD803/S, shodex AD802/S are connected in series and used. Further, the molecular weight of the polyfluorene-based resin which is not cross-linked by the epoxide cross-linking can be measured by the insoluble matter described later, and the extract of the polyfluorene-based resin having the uncrosslinked portion extracted is used. Determination. It is preferred to use a powdery polymer sample prepared by reprecipitating and refining the extract with a large amount of acetone. Here, the polyfluorene-based resin which is not cross-linked, in the case of the present application, is mostly a polyimide-based resin which does not react with an epoxide, but also includes a part even if it has reacted with an epoxide. But it is not completely part of the (not insoluble) part of the network structure.

The number average molecular weight of the polyfluorene-imide resin which is not crosslinked by the epoxy resin of the present invention is preferably a molecular weight equivalent to 10,000 or more and 200,000 or less, more preferably 21,000 to 180,000. More preferably, it is 47,000 or more and 160,000 or less. When the number average molecular weight is less than 10,000, mechanical properties such as bending resistance and folding resistance of the metal foil laminate or the flexible printed wiring board may be insufficient. Further, when the temperature exceeds 200,000, the viscosity of the solution is increased, and molding processing when processing into a metal foil laminate may become difficult. Moreover, the encapsulation property (the depression of the base film layer at the wafer package temperature) tends to deteriorate.

<Acid value of polyimine-based resin> The acid value of the polyimine-based resin before crosslinking of the epoxy resin of the present invention is preferably 5 eq/ton or more and 1000 eq/ton or less, more preferably 10 eq/ton. The above 600 eq/ton or less is more preferably 15 eq/ton or more and 300 eq/ton or less, and particularly preferably 20 eq/ton or more and 160 eq/ton or less. If the acid value is less than 5 eq/ton, it becomes difficult to form a metal foil laminate, and the encapsulation property (the depression of the base film layer at the wafer package temperature) tends to deteriorate. When it is more than 1000 eq/ton, mechanical properties such as bending resistance and folding resistance of the metal foil laminate and the flexible printed circuit board may be insufficient.

<Measurement of acid value> The acid value is determined by using a 1/50N hydrochloric acid (ethanol/dimethylformamide solution, volume ratio = 50/50) titration solution according to JIS K2501, using a potentiometric titration device (Kyoto Electronics ( Stock system, AT310) was titrated at 25 °C. As a sample of the sample, 0.1 g of the powdery polymer used in the measurement of the logarithmic viscosity is added to the mixture of N-methyl-2-pyrrolidone/dimethylformamide (50/50 capacity ratio). The solvent was made into 1 dl and produced. Further, the acid value of the polyfluorene-based resin in the uncrosslinked portion after crosslinking by the epoxide can be extracted by using the polyunsine-based resin having the uncrosslinked portion extracted in the measurement of the insoluble ratio described later. Liquid to determine. It is preferred to use a powdery polymer sample prepared by reprecipitating and refining the extract with a large amount of acetone. Here, the polyfluorene-based resin of the uncrosslinked portion is mostly a polyamidene-based resin which is not reacted with an epoxide in the case of the present application, but also includes a part which has reacted with the epoxide even though Not fully part of the network structure (not insoluble).

The acid value of the polyazonia-based resin of the uncrosslinked portion after crosslinking by the epoxy resin of the present invention is preferably 5 eq/ton or more and 1000 eq/ton or less, more preferably 10 eq/ton or more and 600 eq/ton or less. More preferably, it is 15 eq/ton or more and 300 eq/ton or less, and particularly preferably 20 eq/ton or more and 160 eq/ton or less. When the acid value is less than 5 eq/ton, the molding process when the metal foil laminate is processed becomes difficult, and the encapsulation property (the depression of the base film layer at the wafer package temperature) tends to be deteriorated. When it is more than 1000 eq/ton, mechanical properties such as bending resistance and folding resistance of the metal foil laminate and the flexible printed circuit board may be insufficient.

<The heat-resistant resin composition> In the present invention, by adding an epoxy resin to the polymerization solution of the polyimine-based resin obtained above, reacting and/or blending, a heat-resistant resin composition can be obtained. A varnish for casting a metal foil to be described later. Therefore, the ideal solvent to be used is the same as the aforementioned polymerization solvent. In the heat-resistant resin composition, the total amount of the polyamidene-based resin and the epoxy resin is 30% by mass or more, preferably 50%, when the total solid content of the heat-resistant resin composition is 100% by mass. More than or equal to 70% by mass. If it is less than 30% by mass, encapsulation sometimes deteriorates.

In the crosslinked structure of the present invention, as described above, by adding an epoxy resin to a polyimine-based resin having various properties and using the reaction conditions described later, it is possible to form only the terminal functional group of the polyimine-based resin. The joint structure satisfies both encapsulation, bending resistance, folding resistance, softness, and low rebound.

The epoxy resin used in the present invention can be used alone as a bisphenol A type epoxy resin, a hydrogenated bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a brominated bisphenol A type epoxy resin, a bisphenol S type. Epoxy resin, phenol novolak type epoxy resin, o-cresol novolac type epoxy resin, polyfunctional epoxy propylamine type epoxy resin, epoxy resin containing dicyclopentadiene skeleton, trisepoxypropyl Cyanurate, bisphenol type epoxy resin, lanthanide epoxy resin, containing Skeleton epoxy resin, triphenylmethane type epoxy resin, tetraphenylmethane type epoxy resin, biphenyl type epoxy resin, or rubber modification, urethane modification, etc. An epoxy resin, a heterocyclic epoxy resin, a polyfunctional alicyclic epoxy resin or the like having a glycidyl group. Further, a glycidyl ester such as bisphenol S diglycidyl ether, a glycidyl hexahydrophthalate, a glycidyl diacrylate, or a triepoxypropyl isocyanuric acid Ethylene or aliphatic esters such as esters, tetraepoxypropyldiaminediphenylmethane, etc., such as glycidylamine, 3,4-epoxycyclohexylmethylcarboxylate, epoxidized polybutadiene, epoxidized soybean oil A cyclic epoxide or used as a mixture.

In addition, as long as it is a compound having a functional group reactive with a carboxyl group, an amine group or an isocyanate group which is a terminal functional group of a polyfluorene-based resin, it can be used as a crosslinking agent, and a novolac can be used as needed. An oxetane group-containing compound such as an oxetane resin.

The oxetane group-containing compound is not particularly limited as long as it has an oxetane ring in the molecule and is hardened, for example, 3-ethyl-3-hydroxymethyloxetane, 1,4-bis-{[(3-ethyl-3-epoxypropenyl)methoxy]methyl}benzene, 3-ethyl 3-(phenoxymethyl)oxetane, two [1-ethyl(3-epoxypropane)]methyl ether, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, 3-ethyl-3-{[ 3-(triethoxy)propoxy]methyl}oxetane, 3,3-bis(hydroxymethyl)oxetane, bis[1-hydroxymethyl(3-epoxypropane) Methyl ether, 3,3-bis(hydroxymethyl)oxetane, and propylene oxide-sesquioxane.

These oxetane ring-containing compounds may be used singly or in combination of two or more.

Among the above, an epoxy resin which can simultaneously satisfy encapsulation, bending resistance, folding resistance, flexibility, and low rebound is a bisphenol A epoxy resin, a novolac epoxy resin, and a dicyclopentane Ethylene type epoxy resin, multifunctional epoxy propylamine type epoxy resin, Epoxy resin, biphenyl type epoxy resin. Commercially available products can be directly used, for example, DIC (shared) EPICLON (registered trademark) 840 (bisphenol A epoxy resin), Mitsubishi Chemical Co., Ltd. JER154JER152, JER157S70 (novolac epoxy resin), DIC (Stock) HP-7200 (dicyclopentadiene type epoxy resin), Mitsubishi Gas Chemical Co., Ltd. TETRAD (registered trademark)-X, TETRAD (registered trademark)-C (multifunctional epoxy propylamine type epoxy) Resin), DIC (share) EPICLON (registered trademark) HP-4032 ( Type epoxy resin), YX4000 (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Corporation. More preferably, it is a bisphenol A type epoxy resin, a novolac type epoxy resin, a dicyclopentadiene type epoxy resin, more preferably a phenol novolac epoxidized propylene ether, a cresol novolac epoxidized propylene ether, a bromination Phenolic novolac oxime oxime, phenol cresol novolac epoxifenol, phenolic varnish type epoxy resin, bisphenol A epoxidized propyl ether, brominated bisphenol A diglycidyl ether, etc. The epoxy resin is preferably a phenol novolac oxime oxime of the following formula (2).

[Chemical 2] General formula (2) [n is an integer from 1 to 20]

The epoxy equivalent of the epoxy resin used in the present invention is preferably 10 g/eq or more and 1000 g/eq or less, more preferably 50 g/eq or more and 500 g/eq or less, still more preferably 80 g/eq or more and 200 g/eq or less. When the epoxy equivalent is less than 10 g/eq, mechanical properties such as bending resistance and folding resistance of the metal foil laminate or the flexible printed wiring board may be insufficient. When it exceeds 1000 g/eq, the molding process in the case of processing into a metal foil laminate becomes difficult, and the encapsulation property (the depression of the base film layer at the wafer package temperature) tends to be deteriorated. Further, the measurement of the epoxy equivalent is usually carried out by titration with a potential difference from a perchloric acid acetic acid standard solution in accordance with JIS K 7236.

When the total amount of the polyimide-based resin and the epoxy resin is 100% by mass, the amount of the epoxy resin is preferably 0.1% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 10% by mass or less. Hereinafter, it is more preferably 1% by mass or more and 8% by mass or less, and most preferably 2% by mass or more and 5% by mass or less. When it is less than 0.1% by mass, the encapsulation property (the depression of the base film layer at the wafer package temperature) tends to be deteriorated, and when it exceeds 10% by mass, the metal foil laminate and the flexible printed circuit board are resistant to bending and resistance. Mechanical properties such as folding are sometimes insufficient.

In the present invention, a hardening accelerator may be used as needed. The hardening accelerator is not particularly limited as long as it can promote a hardening reaction between a carboxyl group, an amine group, an isocyanate group and an oxirane ring-containing compound (epoxy resin) which is a terminal functional group of the polyimine-based resin. .

Such a hardening accelerator, for example, an imidazole derivative, an acetamidine (acetoguanamine), guanamine such as benzoguanamine, diaminodiphenylmethane, m-phenylenediamine, m-xylylenediamine, diaminodiphenylphosphonium, dicyanamide, urea, Polyamines such as urea derivatives, melamine, polyvalent hydrazine, organic acid salts and/or epoxy adducts, amine complexes of boron trifluoride, ethyldiamine-S-three 2,4-diamino-S-three , 2,4-diamino-6-dimethylphenyl-S-three Wait three Derivatives, trimethylamine, triethanolamine, N,N-dimethyloctylamine, N- Dimethylamine, pyridine, N-methyl Porphyrin, hexa(N-methyl)melamine, 2,4,6-gin (dimethylaminophenol), tetramethylguanidine, 1,8-diazabicyclo[5,4,0]-7- a tertiary amine such as monoolefin (sometimes referred to as "DBU") or 1,5-diazabicyclo[4,3,0]-5-pinene (sometimes referred to as "DBN"), such Organic phosphines such as organic acid salts and/or tetraphenylborate, polyvinylphenol, polyvinylphenol bromide, tributylphosphine, triphenylphosphine, gin-2-cyanoethylphosphine, etc. a quaternary phosphonium salt such as butyl (2,5-dihydroxyphenyl)phosphonium bromide, hexadecyltributylphosphonium chloride or tetraphenylphosphonium tetraphenylborate; a quaternary ammonium salt such as trimethylammonium chloride or phenyltributylammonium chloride, the above polycarboxylic acid anhydride, diphenylphosphonium tetrafluoroborate, triphenyl Hexafluoroantimonate, 2,4,6-triphenylthiopyranium hexafluorophosphate, Irgacure-261 (manufactured by Vapart Chemical Co., Ltd.), Optomer SP-170 (made by ADEKA) Cationic polymerization catalyst, styrene-maleic anhydride resin, molar reaction such as phenyl isocyanate and dimethylamine, or organic polyisocyanate such as methylphenyl diisocyanate or isophorone diisocyanate and dimethylamine Waiting for molar reactants, etc. These may be used alone or in combination of two or more. Among these, it is preferred that the hardening accelerator is a latent curing agent such as an organic acid salt of DBU or DBN and/or a tetraphenyl borate or a photocationic polymerization catalyst. These may be used alone or in combination of two or more.

The amount of the hardening accelerator to be used can be a conventionally known suitable amount. Usually, it is 0.1 or more and 30 parts by mass or less with respect to 100 parts by mass of the compound (epoxy resin) containing an oxirane ring, and of course, the object of the present invention can be achieved even without a catalyst.

In the present invention, a hardener can be used as needed. As the curing agent for catalyzing the hardening reaction of the epoxy resin, any conventionally known curing agent for epoxy resins can be used. For example: diaminodiphenylmethane, diaminodiphenyl sulfide, diaminobenzophenone, diaminodiphenylphosphonium, diethyltriamine, triethylamine, An amine compound such as dimethylamine, a basic compound such as triphenylphosphine, an imidazole derivative such as 2-alkyl-4-methylimidazole or 2-phenyl-4-alkylimidazole, or phthalic anhydride; An acid anhydride such as tetrahydrophthalic anhydride or trimellitic anhydride, an amine complex of boron trifluoride such as boron trifluoride triethylamine complex, or dicyandiamide. These may be used alone or in combination of two or more.

The blending amount is a conventionally known suitable amount. It is usually 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the compound containing an oxirane ring, but it is possible to achieve the object of the invention even without a hardener. Further, when an acid anhydride is used as the curing agent, the acid anhydride reacts with the epoxide to partially form a carboxyl group, so that the acid value of the resin can be adjusted by using an acid anhydride. That is, the acid anhydride functions not only as a hardener but also to adjust the acid value.

The epoxy resin, or the mixture of the catalyst and the hardener as required, is usually added after the polymerization, and is added to the obtained resin solution to be quantitatively and mixed until uniform. When the epoxy resin is reacted, an epoxy resin of a predetermined amount is added to the resin solution, and then heated and stirred at a temperature of 50 ° C to 200 ° C for 1 hour to 10 hours to achieve. By reacting the epoxy resin, a crosslinked structure can be formed with a small amount of epoxy resin blending.

Further, if necessary, in order to improve various characteristics of the metal foil laminate or the flexible printed wiring board, for example, transparency, mechanical properties, electrical properties, slidability, flame retardancy, etc., the above heat resistance of the present invention may be employed. The resin solution is mixed with other resins or organic compounds, and inorganic compounds, or reacted. For example, lubricants (cerium oxide, talc, anthrone, etc.), adhesion promoters, flame retardants (phosphorus or tri System, aluminum hydroxide, etc., stabilizer (antioxidant, ultraviolet absorber, polymerization inhibitor, etc.), plating activator, organic or inorganic filler (talc, titanium oxide, fluorine polymer particles, pigments, dyes, Calcium carbide, etc.), further, an anthrone compound, a fluorine compound, an isocyanate compound, a blocked isocyanate compound, an acrylic resin, a urethane resin, a polyester resin, a polyamide resin, a phenol resin, a polyimide resin, or the like The resin or the organic compound, or an inorganic compound such as the hardener, cerium oxide, titanium oxide, calcium carbonate or iron oxide can be used in combination within a range not inhibiting the object of the present invention.

<Metal Foil Laminate> A metal foil laminate can be obtained by laminating a casting varnish composed of a heat resistant resin composition prepared as described above and a metal foil. That is, the metal foil lamination system of the present invention contains a laminate of a base film and a metal foil of a heat resistant resin composition. In the present invention, a flexible metal foil laminate is preferred.

<Metal foil> As the metal foil used in the present invention, a copper foil, an aluminum foil, a steel foil, a nickel foil, or the like can be used, and a composite metal foil obtained by laminating these or the like can also be used. It is preferably a copper foil.

Copper foil surface can be treated with organic anti-rust treatment (benzothiazole, benzotriazole, imidazole, etc.), inorganic anti-rust treatment (zinc, chromate, zinc alloy, etc.) decane coupling agent (epoxy decane) Surface treatment such as a coupling agent, an amine decane coupling agent, a mercapto decane coupling agent, or the like, a coating plating treatment, or a baking plating treatment.

The surface roughness (Rz) of the surface (so-called M surface) on which the heat resistant resin composition is laminated is 5.0 μm or less, preferably 2.0 μm or less, and most preferably 1.0 μm or less. When the thickness is more than 5.0 μm, the patterning property is inferior, and the haze value of the resin film layer after the copper foil is removed by etching is increased, so that visibility may be deteriorated. Visibility is a measure of the positional alignment when a semiconductor wafer is packaged. Usually, a CCD camera is used to identify a positioning pattern via a base resin film. Therefore, if it is too low, packaging is sometimes difficult. The lower the lower limit of the surface roughness, the better, and it is not limited, and if it is about 0.1 μm, the object of the invention can be achieved.

More preferably, the M surface has a gloss of 300 or more, preferably 400 or more, more preferably 600 or more, and particularly preferably 800 or more. The gloss is measured in accordance with JIS Z 8741-1997, and is usually irradiated at an incident angle of 60°, and reflected light at 60° is measured. The higher the gloss, the lower the surface roughness, and the less the surface roughness (Rz) fluctuation, etc., so that the surface is smoother. Therefore, the higher the value, the better, and if it is about 800, the object of the present invention can be achieved.

Glossiness, the so-called gloss value, illuminates the measurement light at a certain angle of incidence, and measures the intensity of the light reflected by it at a certain angle. For example, JIS Z 8741-1997 specifies 20°, 45°, 60°. Angle of incidence, angle of reflection, 75°, 85°. In this case, when a high-gloss copper foil is used, the base film layer after the copper foil is removed by etching on the flexible printed circuit board reflects the surface state of the copper foil, and is a film having less irregular reflection and excellent transparency. Layers, and in the case of low gloss, can be considered to have the opposite phenomenon. However, when the glossiness is used as an index, transparency is strictly speaking, and the degree of the scattered light at a certain angle between the incident angle and the reflection angle at a certain angle is not practical in terms of the transparency of the substrate film. . That is, the positioning of the COF substrate is performed, for example, by irradiating visible light of about 400 nm to 800 nm to the substrate, and performing image processing or the like on the identification pattern, but not an angle of 60°, but an incident angle close to a vertical angle. , reflection angle. Therefore, the extent of the disordered reflection of, for example, a near vertical angle in the base film layer after the copper foil is removed by the surface state of the copper foil may not necessarily be related to the high or low gloss. For example, if the incident angle is 5° and the vertical reflection angle is small, the chaotic reflection is small, but the incident angle and the reflection angle are 60°, and the surface state is excessively reflected. When the COF substrate is positioned, the former is closer to practical use.

In view of the above, it is more practical to select a copper foil having a metal foil laminate having excellent reflectance when the visible light of about 400 nm to 800 nm is vertically irradiated onto the substrate, in addition to the glossiness described above. More preferably, the visible light region of 400 nm to 800 nm is preferably 20% or more, more preferably 25% or more, and still more preferably 30% or more. If it is less than 20%, the visibility is not good. The higher the reflectance, the better, and if it is about 80%, the object of the present invention can be attained.

The thickness of the metal foil is not particularly limited, and for example, a metal foil of 3 to 50 μm can be preferably used. The metal foil is usually in the form of a belt, and the length thereof is not particularly limited. Further, the width of the strip-shaped metal foil is not particularly limited, and is generally about 25 to 300 cm, particularly preferably about 50 to 150 cm.

As the above copper foil, a commercially available electrolytic foil or a rolled foil can be used as it is. For example, "HLS" made by Japan Electrolytic Co., Ltd., "F0-WS" manufactured by Furukawa Electric Industrial Co., Ltd., "U-WZ", or "NA-VLP" and "DFF" of Mitsui Metals Mining Co., Ltd. , Fukuda Metal Foil Powder Industry Co., Ltd. "CF-T9D-SVR", "CF-TGD-SV", etc.

The method for producing the metal foil laminate of the present invention is not particularly limited. For example, the casting varnish obtained in the above manner can be applied to one side of the metal foil and then subjected to preliminary drying, heat treatment, or the like.

The coating method is not particularly limited, and a method known from the prior art can be employed. After adjusting the viscosity of the coating liquid by a roll coater, a knife coater, a knife coater, a gravure coater, a die coater, a multi-layer die coater, a reverse coater, a reverse roll coater, or the like, Coated on a metal foil.

In the present invention, the preliminary drying conditions after coating are not particularly limited, and are generally preliminary dried at a temperature lower by 70 ° C to 130 ° C than the boiling point (Tb (° C)) of the solvent used for the casting varnish. If the initial drying temperature is higher than (Tb-70) °C, bubbles appear on the coated surface, and if the drying temperature is lower than (Tb-130) °C, the drying time is elongated and the productivity is lowered. The preliminary drying temperature varies depending on the type of the solvent, and is usually about 60 to 150 ° C, preferably about 80 to 120 ° C. The time required for preliminary drying is generally determined to be an effective time of about 5 to 40% of the solvent remaining in the coating film under the above temperature conditions, generally about 1 to 30 minutes, especially about 2 to 15 minutes. It is preferred to further dry (secondary drying) at a temperature near the boiling point of the solvent or at a temperature higher than the boiling point.

Further, the heat treatment conditions are not particularly limited, and may be carried out at a temperature near the boiling point of the solvent or at a temperature equal to or higher than the boiling point, and is usually from 120 ° C to 500 ° C, preferably from 200 ° C to 400 ° C. When the temperature is less than 120 ° C, the drying time is elongated and the productivity is lowered. When it exceeds 500 ° C, depending on the resin composition, the deterioration reaction proceeds, and the base film layer may become brittle. Further, the crosslinking point with the epoxy resin is thermally decomposed, oxidatively deteriorated, and the encapsulation property is deteriorated. The time required for the heat treatment is generally set to an effective time until the solvent residual ratio in the coating film disappears under the above temperature conditions, and is usually about several minutes to several tens of hours.

In the present invention, preliminary drying and heat treatment can be carried out in a passive gas atmosphere or under reduced pressure. In order to suppress deterioration of the resin and thermal decomposition and deterioration of the crosslinking point, it is preferred to use a combination under reduced pressure and a passive gas atmosphere. Examples of the passive gas include nitrogen gas, carbon dioxide gas, helium gas, and argon gas. However, it is preferred to use nitrogen gas which is easily obtained. Further, when it is carried out under reduced pressure, it is preferably carried out at a pressure of about 10 ^-5 to 10 ³ Pa, preferably about 10 ^-1 to 200 Pa.

In the present invention, the drying method of the preliminary drying and the secondary drying is not particularly limited, and it can be carried out by a conventionally known method such as a roll supporting method or a floating method. Further, the heat treatment may be carried out by a tenter type or the like in a continuous heat treatment in a heating furnace or in a wound state, and heat-treated in a batch oven. In the case of a batch type, it is preferable to wind it so that the coated surface and the non-coated surface are not in contact with each other.

The thickness of the layer of the heat resistant resin composition of the metal foil laminate (hereinafter also referred to as the base film or the base film layer) can be selected from a wide range, but the thickness after the absolute drying is generally about 3 to 300 μm, preferably. It is about 10~100μm. When the thickness is less than 3 μm, mechanical properties such as film strength and workability are inferior, and in the packaging step of the COF substrate, the transportability of the carrier tape and the packageability of the wafer are deteriorated. On the other hand, when the thickness exceeds 300 μm, properties such as flexibility and workability (dryness, coatability) and the like tend to decrease. In the COF substrate, folding resistance occurs, and in particular, the folding resistance of the fine pitch, the deterioration of the bending resistance, and the rebound are caused. Further, a surface treatment may be applied as needed. For example, surface treatment such as hydrolysis, corona discharge, low temperature plasma, physical roughening, and easy adhesion coating treatment may be applied.

<Base film insoluble ratio of metal foil laminate> In the present invention, the base film insoluble ratio of the metal foil laminate after preliminary drying and heat treatment is preferably 40% or more, more preferably 75% or more, and still more preferably The best is 80% or more, and the best is 86% or more. Conversely, the preliminary drying and heat treatment conditions are as described above so that the insolubility falls within a predetermined range. In other words, by appropriately setting the logarithmic viscosity, the number average molecular weight, and the blending amount of the epoxy resin of the polyimine-based resin, the composition or acid value of the polyimide pigment can be set to a predetermined range. Achieve the ideal insolubility. If the insolubility is less than 40%, the encapsulation is insufficient. There is no special upper limit for the insoluble rate, and if it is about 90%, the object of the present invention can be sufficiently achieved. Further, an N-methyl-2-pyrrolidone solution containing the obtained dissolved portion of the base film layer (sometimes referred to as "extracted extract of a polyfluorene-based resin having an uncrosslinked portion") is available as described above. "Measurement of logarithmic viscosity", "measurement of average molecular weight", and "measurement of acid value".

<Measurement of insoluble rate> The insoluble ratio is a base film layer of a portion obtained by removing only the metal foil from the metal foil laminate in N-methyl-2-pyrrolidone, and is carried out in a solution having a concentration of 0.5% by mass. The insoluble component of the resin layer after the dissolution treatment at 100 ° C for 2 hours is represented by the following formula. Insoluble rate (%) = [Mi/Mf] × 100 (wherein Mi represents the weight (g) of the substrate film layer after the dissolution treatment, and Mf represents the weight (g) of the substrate film layer before the dissolution treatment.)

In the double-sided metal foil laminate having a metal foil on both sides of the present invention, the resin faces of the metal foil laminate obtained by laminating only the single-sided laminated metal foil formed as described above can be laminated and the like. It is produced by a conventionally known method of laminating or bonding by a conventionally known method via an adhesive layer. The lamination method is not particularly limited, and may be a conventionally known method such as roll lamination, press lamination, or belt press lamination, and the lamination temperature is usually not less than the Tg of the resin, and preferably 200 to 500 ° C, more preferably 250 ° C. ~450 ° C, and more preferably 330 ° C ~ 400 ° C. When the temperature is less than 200 ° C, the adhesiveness is insufficient. When the temperature exceeds 500 ° C, the resin layer is deteriorated, the mechanical properties are lowered, or the crosslinking point is thermally decomposed or thermally deteriorated, and the encapsulation property is deteriorated. Further, the lamination time is not particularly limited and is usually from 10 seconds to 10 hours, preferably from 1 minute to 1 hour, and more preferably from 3 minutes to 30 minutes. If it is less than 10 seconds, the adhesiveness is insufficient, and if it exceeds 10 hours, the resin layer will deteriorate and the mechanical properties will fall. Further, the crosslinking point is thermally decomposed and thermally deteriorated, and the encapsulation property is deteriorated.

When the adhesive layer is laminated via an adhesive, the composition of the adhesive is not particularly limited, and an acrylonitrile butadiene rubber (NBR) adhesive, a polyamide adhesive, a polyester adhesive, or a polyester urethane can be used. Adhesives such as adhesives, epoxy resins, acrylic resins, polyimine resin resins, polyamidoximine resin resins, polyester phthalimide resins, etc., considering encapsulation, bending resistance, and folding resistance From the viewpoints of flexibility, low resilience, etc., it is preferably a polyimine resin, a polyamidimide resin, a polyester phthalimide resin, or an epoxy resin blended in the resin. A resin composition is preferred.

The thickness of the adhesive layer is preferably from about 1 to 30 μm. The thickness of the adhesive is not particularly limited as long as it does not impede the performance of the flexible printed wiring board. If the thickness is too small, sufficient adhesion may not be obtained, and if the thickness is too thick, bending resistance may occur. , folding resistance, softness, and low rebound characteristics are reduced.

<Flexible Printed Circuit Board>

According to the metal foil laminate of the present invention described above, a flexible printed wiring board can be produced by a conventionally known treatment in accordance with, for example, a subtractive method. The flexible printed circuit board obtained by the present invention does not undergo deformation of the substrate film layer even at a wafer package temperature of 400 ° C or higher. The folding resistance is measured before the surface of the circuit (before the surface of the circuit is covered with a solder resist or a heat-resistant film), and the value of the folding endurance test is measured according to JIS C 5016, more than 190 times, preferably 700 times or more, more preferably 1,000 times. More than once. Further, the Gray softness (or bending repulsive force) which is an index of low resilience is lower than 800 mg, preferably 760 mg or less, more preferably 600 mg or less. When the solder resist of the conductor circuit is coated or the surface of the circuit is covered for contamination or damage of the circuit surface, the heat-resistant film may be bonded to the wiring board via the adhesive (the base substrate on which the conductor circuit is formed). A method or a method of applying a liquid coating agent to a wiring board by a screen printing method.

As the heat-resistant film, a film such as a polyimide resin, a polyamidimide resin or a polyester phthalimide resin can be used, and the encapsulation property, bending resistance, folding resistance, flexibility, and low bounce are considered. From the viewpoint of characteristics and the like, a film obtained from the polyimide-based resin of the present invention is preferred.

As the adhesive, an acrylonitrile butadiene rubber (NBR)-based adhesive, a polyamide-based adhesive, a polyester adhesive, a polyester urethane adhesive, an epoxy resin, an acrylic resin, or a poly An adhesive such as a quinone imine resin, a polyamidoximine resin, or a polyester phthalimide resin, but considering encapsulation, bending resistance, folding resistance, flexibility, and low resilience characteristics, A polyimine resin type, a polyamidoximine resin type, or a resin composition in which an epoxy resin is blended in the resin is preferable.

As the liquid coating agent, a conventionally known epoxy-based or polyimide-based ink can be used, but from the viewpoints of encapsulation, bending resistance, folding resistance, flexibility, and low rebound property, it is preferred. A polyimide composition, a polyamidimide resin, or a resin composition in which an epoxy resin is blended in the resin.

Further, an adhesive sheet such as an epoxy-based or a polyimide-based polyimide may be directly bonded to a wiring board. In this case, considerations such as encapsulation, bending resistance, folding resistance, flexibility, and low resilience characteristics may be considered. Preferably, it is a polyimine resin type, a polyamidimide resin type, or a resin composition in which an epoxy resin is blended in these resins.

The wiring pattern of the circuit can be formed into any pattern. Even if a circuit having a particularly fine wiring pattern has been applied, since the flexible printed circuit board of the present invention exhibits a high level of performance, the flexible printed circuit board of the present invention is particularly advantageous in a circuit to which a fine wiring pattern is applied.

Specifically, the roughness of the circuit wiring may be 30 μm or less, the roughness of the wiring may be 20 μm or less, and the roughness of the wiring may be 10 μm or less. The interval between the wirings may be 30 μm or less, or may be 20 μm or less, or may be 10 μm or less.

In the case of the COF substrate, for example, a fine pattern can be formed by a photolithography method or the like on a copper foil surface of a two-layer metal foil laminate, and tin and the like can be plated on a necessary portion, and a solder resist can be coated and produced. The package of the semiconductor wafer can be packaged by a conventionally known method such as Au-Au bonding or Au-Sn bonding using a COF conductive pattern which has been plated and a connection terminal (bump) of the wafer.

<Application of Flexible Printed Circuit Board> The flexible printed circuit board manufactured in this manner is suitable for a COF substrate, and can be widely used for component package substrates for display devices such as liquid crystal displays, plasma displays, and organic EL displays, or smart phones. A substrate material for IC packaging of an electronic device such as a tablet terminal, a digital camera, a portable game machine, and the like, such as a cable for connecting a substrate, an operation switch unit substrate, and the like, which are small, lightweight, and thin. [Examples]

The invention is further described in detail below with reference to the examples, but the invention is not particularly limited by the examples. Further, the production of the metal foil laminate and the evaluation samples (resin powder, base film, flexible printed circuit) for evaluating various characteristics of the resin, the flexible metal foil laminate, and the flexible printed circuit board The method of making and evaluating the board) is as follows. Further, whether or not the functional group is at the end of the polymer can be confirmed by the molecular weight, the functional group equivalent, and the quantitative result of the functional group derived from NMR.

<Measurement of Logarithmic Viscosity of Polyimide Ion Resin> A powdery polymer sample prepared by reprecipitating and refining a solution containing a polyimine-based resin in a large amount of acetone was used. The powder sample was dissolved in N-methyl-2-pyrrolidone to have a polymer concentration of 0.5 g/dl, and the solution viscosity and solvent viscosity of the solution were measured at 30 ° C using a UBBELOHDE type viscosity tube. The logarithmic viscosity value is calculated from the following equation. Logarithmic viscosity (dl/g)=[ln(V1/V2)]/V3 {In the above formula, V1 represents the viscosity of the solution measured by the UBBELOHDE type viscosity tube, and V2 represents the viscosity of the solvent measured by the UBBELOHDE type viscosity tube, V1 And V2 is determined by the time when the polymer solution and the solvent (N-methyl-2-pyrrolidone) pass through the capillary of the viscosity tube. Further, V3 is a polymer concentration (g/dl). }

<Measurement of Functional Group of Polyimine Ion Resin> The measurement of the functional group in the polyimide-based resin was carried out by calculating the amine value, the isocyanate value, and the acid value as follows.

<Measurement of Acid Value of Polyimide Ion Resin> 0.1 g of powdery polymer used for the measurement of logarithmic viscosity, to which N-methyl-2-pyrrolidone/dimethylformamide was added (50/ The mixed solvent of 50 capacity ratios was made to be 1 dl in total, and a titrated sample sample was prepared. Next, a titration solution of 1/50 N potassium hydroxide (ethanol/dimethylformamide solution, volume ratio = 50/50) was titrated using a potentiometric titration apparatus (manufactured by Kyoto Electronics Co., Ltd., AT310). The temperature was set at 25 ° C and measured according to JIS K2501 (or according to Kyoto Electronic Application Note No TII-9800 ver. 01).

<Measurement of Isocyanate Price of Polyimide Ion Resin> The same as the measurement of the acid value, a sample sample to be titrated is prepared according to JIS K 7301 (or according to Kyoto Application Note No TII-98003). The solution was titrated with 1/50 N hydrochloric acid (ethanol/dimethylformamide solution, volume ratio = 50/50), and di-n-butylamine was subjected to reverse titration using a potentiometric titration apparatus (manufactured by Kyoto Electronics Co., Ltd., AT310).

<Measurement of amine valence of polyimide-based resin> The same as the measurement of the acid value, a titrated sample sample was prepared, and 1/50 N hydrochloric acid (ethanol/dimethylformamide solution, capacity ratio = 50) was prepared. /50) The titration solution was titrated using a potentiometric titration apparatus (manufactured by Kyoto Electronics Co., Ltd., AT310). Determination by Kyoto Electronics (share) Application Note TII-97003.

<Measurement of Functional Group of Polyimide Ion Resin> 100 mg of a polyimide-based resin was dissolved in 0.6 ml of DMSO-d6 to prepare a sample. The prepared sample was measured by ¹ H-NMR. Further, the volume ratio of the polyimine-based resin to DMSO-d6 was 1:1, and the sample was prepared and measured by ¹³ C-NMR.

<Measurement of Average Molecular Weight of Polyimide Ion Resin> The measurement of the number average molecular weight and the polydispersity was measured by the GPC method. The sample for measurement was prepared by diluting a resin varnish obtained by polymerization into a concentration of 0.5 g/dl with N-methyl-2-pyrrolidone dissolved in 0.1% by mass of lithium bromide. The mobile phase uses N-methyl-2-pyrrolidone in which 0.1% by mass of lithium bromide is dissolved, and the detector uses a refractometer (made by Showa Denko Co., Ltd., SE-51), and is made of standard polystyrene of the following molecular weight. The measured line is measured. (1)6770000 (2)2870000 (3)1260000 (4) 355000 (5)102000 (6)43900 (7)9500 (8)5400 (9)2800 In addition, the pipe string will be shodex AD800P, shodex AD805/S, Shodex AD804/S, shodex AD803/S, and shodex AD802/S are connected in series.

<Method for Producing Metal Foil Laminate> The resin solution obtained in each of the examples and the comparative examples described later was applied by a knife coater to an electrolytic copper foil having a thickness of 12 μm (CF-T9D-SVR manufactured by Fukuda Metal Foil Powder Co., Ltd.) The surface roughness Rz (1.1 μm) was such that the thickness after drying became 30 μm. Next, after drying at a temperature of 50 ° C to 100 ° C to a transparent and non-adhesive state, the lower and upper ends of the frame are fixed in a stainless steel frame, and at 200 ° C for 60 minutes, at 220 ° C for 60 minutes, at 260 under vacuum. Heat treatment was carried out under the conditions of 10 ° C and 10 ° C for 10 minutes.

<Fold-resistance test; index of bending resistance and low resilience> Flexibility of a flexographic printed wiring board or a metal foil laminate, and a folding resistance of a low resilience (rebound force) The sample for evaluation was prepared by JIS C 5016, and was measured under the conditions of a load of 500 g and a bending diameter of 0.38 mm.

<Method for Producing Substrate Film> A test sample (base material film) for evaluation of the softness, insolubility, and encapsulation of the gel, using a metal foil laminate obtained in each of the examples and the comparative examples described later at 40 ° C, The copper foil was etched and fabricated in a 35% copper (II) chloride solution.

<Gray-type softness (bending repulsive force): index of flexibility and low resilience> As a metal foil laminate, the softness of the flexible printed circuit board, and the low resilience index, each implementation will be implemented. The film (base film) obtained by etching and removing the metal layer of the metal foil laminate obtained in the examples and the comparative examples was measured by the following method under the following conditions. The Togo Industries Co., Ltd. (German) Co., Ltd. was used to measure the value. The measurement was performed by mounting the film test piece on the movable arm chuck and rotating it at 2 rpm, when the lower end of the film test piece was removed from the pendulum. Scale. Measuring device; Gurley Stiffness Tester manufactured by Toyo Seisakusho Co., Ltd. Sample size; 25.4 mm (width) × 88.9 mm (length) × 20 μm (thickness) Arm rotation speed; 2 rpm

<Insoluble ratio; scale of cross-linking degree> The base film was dissolved in N-methyl-2-pyrrolidone to obtain a 0.5 mass% N-methyl-2-pyrrolidone solution of the base film layer. The preparation of the solution was carried out using a 100 ml Erlenmeyer flask. Next, the solution was heat-treated at 100 ° C for 2 hours (in a 100 ° C oil bath, the flask containing the solution was immersed and allowed to stand) and cooled to room temperature, and the insoluble component in the Erlenmeyer flask was 100 ml. After washing with N-methyl-2-pyrrolidone, the insoluble components were separated by filtration through a glass filter (3G-2). Thereafter, vacuum drying was carried out for 20 hours at 200 ° C together with a glass filter, and the weight was measured, and the weight of the previously determined glass filter was subtracted from the value, and the weight of the insoluble component was measured. The weight (Mi) of the insoluble component and the weight (Mf) of the resin film obtained in this manner are calculated according to the following formula. Insoluble rate (%) = [Mi/Mf] × 100 (wherein Mi represents the weight (g) of the insoluble component, and Mf represents the weight (g) of the resin film.)

<Packageability; Index of the latitude of the IC wafer bumps> The IC wafer was placed on the substrate film, and a thermocompression bonding test was performed under the following conditions using a flip chip bonding machine (M95 manufactured by HISOL Corporation). The base film after the test was observed by SEM, and the amount of deformation due to the sag of the wafer bump was measured, and it was evaluated as ×, 2 μm or less at 5 μm or more, and was evaluated as ○ at 1 μm or less. Bonding head tool temperature; 400 ° C pedestal temperature; 100 ° C pressure; 20 mgf / μm ²

<Measurement of Solution Viscosity> The viscosity of the solution was measured by a No. 6 rotor and a 10 rpm B-type viscometer manufactured by Toyo Keiki Co., Ltd.

(Example 1) In a reaction vessel, 211.3 g (1.10 mol) of trimellitic anhydride, 132.1 g (0.50 mol) of o-toluidine diisocyanate, and 4,4'-diphenylmethane were added under a nitrogen stream. 125.3 g (0.50 mol) of isocyanate, 0.6 g of potassium fluoride, and 2500 g of N-methyl-2-pyrrolidone (purity: 99.9%) were heated to 100 ° C and maintained for 5 hours. Next, the reaction was carried out at 130 ° C for 3 hours, N-methyl-2-pyrrolidone was added, and the concentration was adjusted so that the viscosity of the solution was 400 dPa ‧ s, and it was cooled to room temperature. The obtained polyamidoximine resin (which is a polyamidoximine composition A) was dissolved in a polymerization solvent, and the properties of each resin of logarithmic viscosity, acid value, and number average molecular weight are shown in Table 1. Thereafter, 24 g of a phenol novolac type epoxy resin (JER154 manufactured by Mitsubishi Chemical Corporation) (6 mass% based on the total solid content) was blended to prepare a varnish for casting. Next, a metal foil laminate was produced using the obtained varnish for casting, and a flexible printed circuit board for evaluation of folding endurance, insolubility, Gray softness (indicator of low resilience), and packageability evaluation were produced. Each of the substrate films was evaluated for each characteristic. The results are shown in Table 1.

(Example 2) Only the acid component of Example 1, i.e., trimellitic anhydride, was changed to 1.02 mol, and the logarithmic viscosity and molecular weight of Table 1 were appropriately adjusted to prepare a polyimide quinone imine resin varnish. The polyamidoximine resin varnish obtained in Example 2 was dissolved in a solvent, and the resin properties of the obtained resin varnish were as shown in Table 1. Thereafter, 12 g of a phenol novolac type epoxy resin (JER154 manufactured by Mitsubishi Chemical Corporation) (3 mass% based on the total solid content) was blended to prepare a varnish for casting. Next, a metal foil laminate was produced using the obtained varnish for casting, and a flexible printed circuit board for evaluation of folding endurance, insolubility, Gray softness (indicator of low resilience), and packageability evaluation were produced. Each of the substrate films was used, and each characteristic was evaluated. The results of the characteristic evaluation are shown in Table 1.

(Comparative Example 1) The polyanisinimide resin varnish was prepared by changing the logarithmic viscosity and molecular weight of Table 1 to 1.15 moles of the acid component of Example 1 and adjusting it to 1.15 moles. The polyamidoximine resin varnish obtained in Comparative Example 1 was dissolved in a solvent, and the resin characteristics of the obtained resin varnish were as shown in Table 1. Thereafter, 4 g of a phenol novolak type epoxy resin (JER154 manufactured by Mitsubishi Chemical Corporation) (1% by mass based on the total solid content) was blended to prepare a varnish for casting. Next, a metal foil laminate was produced using the obtained varnish for casting, and a flexible printed circuit board for evaluation of folding endurance, insolubility, Gray softness (indicator of low resilience), and packageability evaluation were produced. Each of the base films was evaluated for each characteristic. The results of the characteristic evaluation are shown in Table 1.

(Example 3) In a reaction vessel, 161.4 g (0.84 mol), 3,3', 4,4'-benzophenonetetracarboxylic dianhydride 50.8 g (0.16 mol) of trimellitic anhydride were added under a nitrogen stream. , 3,3',4,4'-biphenyltetracarboxylic dianhydride 15.5 g (0.05 mol), o-tolidine diisocyanate 264.3 g (1.00 mol), potassium fluoride 0.6 g, and N- 2230 g of methyl-2-pyrrolidone (purity 99.9%) was heated to 100 ° C and the reaction was maintained for 6 hours. Next, the reaction was carried out at 130 ° C for 4 hours, N-methyl-2-pyrrolidone was added, the concentration was adjusted so that the viscosity of the solution became 300 dPa ‧ s, and it was cooled to room temperature. The obtained polyamidoximine resin (which is a polyamidoximine composition B) was dissolved in a solvent, and the properties of each resin of logarithmic viscosity, acid value, and number average molecular weight are shown in Table 1. Thereafter, 12 g of a phenol novolac type epoxy resin (JER154 manufactured by Mitsubishi Chemical Corporation) (3 mass% based on the total solid content) was blended to prepare a varnish for casting. Next, a metal foil laminate is produced by using the obtained varnish for casting, and a flexible printed circuit board for evaluation of folding endurance, insolubility, Gray softness (index of low resilience), and encapsulation property are produced. Each of the substrate films used was evaluated and each characteristic was evaluated. The results are shown in Table 1.

(Examples 4, 5, 6, 7, 8, 9, 10, and Comparative Examples 2, 3, 4, and 5) The molar ratio between each constituent element of all the acid components of Example 3 was maintained, and only the entire acid was used. The total molar amount of the components was changed as shown in Table 1, and the logarithmic viscosity and molecular weight of Table 1 were appropriately adjusted to prepare a polyamidoximine resin varnish. The polyamidoquinone imine resins obtained in Comparative Examples 2, 3, 4, and 5 of Examples 4, 5, 6, 7, 8, 9, 10 were all dissolved in a solvent, and the properties of the resins are shown in Table 1. Thereafter, in the same manner as in Example 3, the type of the epoxy resin was changed to the content shown in Table 1 to prepare a varnish for casting. Next, a metal foil laminate was produced using the obtained varnish for casting, and a flexible printed circuit board for evaluation of folding endurance, insolubility, Gray softness (indicator of low resilience), and packageability evaluation were produced. Each of the substrate films was used and each characteristic was evaluated. The results of the characteristic evaluation are shown in Table 1.

(Example 11) In a reaction vessel, 150.1 g (0.51 mol%), 3,3', 4, 4'- of 3,3',4,4'-biphenyltetracarboxylic dianhydride was added under a nitrogen stream. Diphenylphosphonium tetracarboxylic dianhydride 182.6 g (0.51 mol%), o-tolidine diisocyanate 264.3 g (1.00 mol%), potassium fluoride 0.6 g, and N-methyl-2-pyrrolidone ( The purity was 99.9%) 2890 g, the temperature was raised to 100 ° C, and the reaction was maintained for 6 hours. Next, the reaction was carried out at 130 ° C for 2 hours, N-methyl-2-pyrrolidone was added, the concentration was adjusted so as to have a solution viscosity of 400 dPa ‧ s, and cooled to room temperature. The obtained polyimine resin (which is a polyimine composition A) was dissolved in a solvent, and the resin properties of the logarithmic viscosity, the acid value, and the number average molecular weight are shown in Table 1. Thereafter, 5 g of a phenol novolak type epoxy resin (JER154 manufactured by Mitsubishi Chemical Corporation) (1 mass% based on the total solid content) was blended to prepare a varnish for casting. Next, a metal foil laminate was produced using the obtained varnish for casting, and a flexible printed circuit board for evaluation of folding endurance, and insolubility, Gray softness (indicator of low resilience), and packageability evaluation were produced. Each of the substrate films was used, and each characteristic was evaluated. The results are shown in Table 1.

(Example 12 and Comparative Examples 6, 7, and 8) The molar ratio between the respective constituent elements of all the acid components of Example 11 was maintained, and only the total molar amount of all the acid components was changed as shown in Table 1. Adjusted to logarithmic viscosity and molecular weight, and made into a polyimide resin varnish. The polyimine resins obtained in Example 12 and Comparative Examples 6, 7, and 8 were all dissolved in a solvent, and the properties of the resins are shown in Table 1. Thereafter, in the same manner as in Example 11, the type of the epoxy resin was changed to the contents shown in Table 1, and a varnish for casting was prepared. Then, in the same manner as in Example 11, a metal foil laminate was produced to produce a flexible printed circuit board for evaluation of folding endurance, insolubility, Gray softness (indicator of low resilience), and encapsulation property. Each of the substrate films used was evaluated and each characteristic was evaluated. The results of the characteristic evaluation are shown in Table 1.

(Comparative Example 9) A polyamidoximine resin varnish was prepared in the same manner as in Example 1 except that all the acid components were trimellitic anhydride (0.99 mol) and trimellitic acid (0.11 mol). The polyamidoximine resin was dissolved in a solvent, and the properties of the resin are shown in Table 1. Thereafter, 4 g of a phenol novolac type epoxy resin (JER154 manufactured by Mitsubishi Chemical Corporation) (1 mass% based on the total solid content) was blended to prepare a varnish for casting. Then, in the same manner as in the first embodiment, a metal foil laminate was produced to produce a flexible printed circuit board for evaluation of folding endurance, insolubility, Gray softness (indicator of low resilience), and packageability evaluation. Each of the substrate films was used and each characteristic was evaluated. The results of the characteristic evaluation are shown in Table 1.

【Table 1】

In Table 1, the epoxy blending amount (% by mass) represents the blending amount (% by mass) of the epoxy resin when the total amount of the polyimide pigment and the epoxy resin is 100% by mass. Further, polyamidoquinone A, polyamidimide B, polyamidimide C, and polyimine A are all soluble in N-methyl-2-pyrrolidone (purity 99.9%) 10% by mass or more. Further, in Examples 1 to 12 and Comparative Examples 1 to 8, polyamidoquinone A, polyamidimide B, and polyimine A were known from the production method, but the acid value and the amine value were used. For the determination of the isocyanate valence and the NMR, any of the resins has a carboxyl group, an amine group, and an isocyanate group at the terminal. The polyamidoguanide C of Comparative Example 9 was found to have a carboxyl group in addition to the terminal when measured by the same analytical method. [Industry Utilization]

The metal foil laminate of the present invention and the flexible printed circuit board obtained thereby are used when the semiconductor wafer is bonded to the metal wiring, and the wafer is hidden from the base film layer (encapsulation property) or when the substrate is bent and packaged. The bounce, which is considered to be a problem, is reduced, and the bending resistance, the folding endurance, and the flexibility are excellent (panel assembly property). As a result, a flexible printed circuit board, such as a flip chip, which can directly load electronic components such as ICs and LSIs, such as liquid crystal display devices, smart phones, and tablet terminals, which are widely used in miniaturization, weight reduction, and slimming, can be widely used. (Chip on Film) substrate.

no.

no

Claims (10)

A metal foil laminate obtained by laminating a heat-resistant resin composition containing a polyimine-based resin obtained by crosslinking an epoxy resin on at least one side of a metal foil to obtain a base film and a metal foil The metal foil laminate satisfies the following (a) and (b); (a) when the total amount of the polyimide resin and the epoxy resin is 100% by mass, the blending amount of the epoxy resin is 0.1 mass (b) Addition of N-methyl-2-pyrrolidone to the base film obtained by removing the metal foil from the metal foil laminate, and the concentration of the base film is 0.5% by mass, and is 100%. The insolubility after heat treatment at ° C for 2 hours was 40% or more. For example, the metal foil laminate of claim 1 further satisfies the following (c) and/or (d); (c) the logarithmic viscosity of the polyamidene resin before crosslinking, in N-methyl- 2-pyrrolidone (polymer concentration: 0.5 g/dl) and 0.40 dl/g or more and 3.50 dl/g or less under the measurement conditions of 30 ° C; (d) Polycondensation of uncrosslinked portion after crosslinking by epoxy resin The logarithmic viscosity of the imine resin is 0.40 dl/g or more and 3.50 dl/g or less in N-methyl-2-pyrrolidone (polymer concentration: 0.5 g/dl) and under the measurement conditions of 30 °C. The metal foil laminate according to claim 1 or 2 further satisfies the following (e) and/or (f); (e) the number average molecular weight of the polyamidene resin before crosslinking is 10,000 or more and 200,000 the following. (f) The polyamidimide-based resin having an uncrosslinked portion after crosslinking by an epoxy resin has a number average molecular weight of 10,000 or more and 200,000 or less. The metal foil laminate according to claim 1 or 2 further satisfies the following (g) and/or (h); (g) the acid value of the polyamidene resin before crosslinking is 5 eq/ton or more 1000 eq/ton or less; (h) The polyvalent imide resin having an uncrosslinked portion after crosslinking by an epoxy resin has an acid value of 5 eq/ton or more and 1000 eq/ton or less. The metal foil laminate of the first or second aspect of the patent application further satisfies the following (i); (i) when the total solid content of the heat resistant resin composition is 100% by mass, the polyimide resin and The total blending amount of the epoxy resin is 30% by mass or more. The metal foil laminate according to claim 1 or 2 further satisfies the following (j); (j) the polyamidimide resin is a polyamidoximine resin, and the structure of the polyamidoximine resin The unit contains the repeating structural unit represented by the formula (1): 5 mol% or more and 99 mol% or less; Formula 1). The metal foil laminate according to claim 1 or 2 further satisfies the following (k); (k) the epoxy resin is a phenol novolak epoxidized propylene ether of the following general formula (2) [Chemical 2] General formula (2) [n is an integer of 1 to 20]. A flexible printed circuit board comprising the metal foil laminate according to any one of claims 1 to 7. For example, the flexible printed circuit board of claim 8 is more than 190 times in accordance with the folding test of JIS C 5016. A flexible printed circuit board according to claim 8 or 9, wherein the Gray type softness is less than 800 mg.