JP2008038084A - Adhesive sheet, metal-laminated sheet and printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive sheet excellent in flatness and homogeneity and slight in the volatilization of polymer-derived decomposition products when undergoing high-temperature processing or services, to provide a metal-laminated sheet with metallic foil laminated on the above adhesive sheet, and to provide a printed wiring board obtained by circuit processing of the above metal-laminated sheet. <P>SOLUTION: The adhesive sheet is such that at least one side of a base film is provided with a thermoplastic adhesive layer, wherein the amount of decomposition products derived from the polymer is 0.01-8 ppm. The metal-laminated sheet is such that the above adhesive sheet is laminated with metallic foil. The printed wiring board is such as to be obtained by circuit processing of the above metal-laminated sheet. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an adhesive sheet used for forming an insulating layer in a printed wiring board or the like used for an electronic device, a flexible printed wiring board or the like for reducing the size and weight of a component, and a metal foil for the adhesive sheet. The present invention relates to a laminated metal laminated sheet and a printed wiring board obtained by processing the metal laminated sheet. More specifically, the present invention relates to an adhesive sheet and a metal laminate sheet for the flexible printed circuit board used for TAB, COF, PGA, BGA, CSP, LOC tape, etc. in semiconductor packaging and the like. More particularly, the present invention relates to a metal laminated sheet after metal lamination and a printed wiring board obtained by processing the metal laminated sheet, and a metal laminated sheet and printed wiring board with less warpage and curl.

When an adhesive sheet or an adhesive film is used to form an insulating layer in a printed wiring board or the like, a so-called prepreg in which a glass fiber cloth is impregnated with an uncured epoxy resin or the like has been used. Also, an aramid fiber fabric is used instead of the glass fiber fabric. These prepregs have a thick cloth and cannot meet the demand for lightening in recent years.
In recent years, electronic devices have been improved in functionality, performance, and size, and there is a demand for downsizing and weight reduction of electronic components used therewith. For this reason, multilayer printed wiring boards, semiconductor element packaging methods, and wiring materials or wiring components for mounting them have been required to have higher density, higher functionality, and higher performance. A material excellent in heat resistance, electrical reliability, adhesiveness, and insulation that can be suitably used as a high-density packaging material such as semiconductor packages, COL and LOC packages, MCM, and FPC materials such as multilayer flexible printed wiring boards. It has been demanded.
Various proposals have been made in order to achieve reduction in weight (lightness) as a result of forming an insulating layer on a printed wiring board or the like and forming the insulating layer.

It is known that various epoxy resins with relatively high heat resistance are used as the insulation layer, but the insulation from the meaning that the dielectric loss tangent is larger, such as non-uniformity of the insulation layer due to non-uniform flow and resin contamination. Has the problem of lack of reliability.
In order to solve the above problem, an adhesive film in which a resin from a silicone copolymer polyimide resin and an epoxy resin is provided on a temporary support with an adhesive layer thickness of 50 μm has been proposed (see Patent Document 1). Although this method is also excellent in permeability between circuits (conductors), the above-mentioned problem cannot be solved entirely, and a certain thickness of the insulating layer cannot be guaranteed, and the characteristics There is a problem in forming an insulating layer such as a high-frequency circuit board that requires strict impedance guarantee.
It has also been proposed to use a thermoplastic polyimide resin (see Patent Documents 2, 3, and 4).
Furthermore, a film in which an adhesive layer composed of a thermoplastic polyimide and a thermosetting resin is provided on at least one surface of the polyimide film has also been proposed (see Patent Document 5).
Furthermore, the polyimide long film with few curls in 25 degreeC is also proposed by making the ratio of the orientation of a polyimide long film front and back into a predetermined value or less (refer patent document 6).
JP 2003-089784 A JP 2000-143981 A JP 2000-144092 A JP 2003-306649 A JP 2003-011308 A JP 2000-085007 A

The use of a substrate film made of a conventionally known polyimide film or polyimide benzoxazole film is inferior in heat resistance compared to the use of a substrate made of ceramic, and warping and distortion occur when electronic parts are produced due to physical property differences in the film. There was a problem that it was easy. In order to eliminate the warp and distortion of the film, measures have been taken to reduce the apparent warp of the film by heat treatment under stretching. However, even if the apparent warpage of the film, that is, the manifested warpage of the film, can be eliminated, it is necessary to process at a high temperature particularly when applied as an electronic component. The problem that the existing strain becomes obvious and the curling occurs has not been solved. In addition, there is a problem of product deterioration due to dielectric breakdown or peeling due to volatilization of polymer-derived decomposition products during high-temperature processing or use.
Therefore, even when the film has a small apparent warp, curling occurs when processing or using it, leading to a decrease in production yield, and it is often difficult to obtain high-quality electronic components due to evaporation of the solvent. .

  The present invention is excellent in flatness and homogeneity suitable as a base material for electronic parts, and has little warpage and curl even when subjected to high temperature processing, and by volatilization of polymer-derived decomposition products during high temperature processing and use. Adhesive sheet using polyimide film with excellent heat resistance without product deterioration due to dielectric breakdown or peeling as a base film, metal laminated sheet with metal foil laminated on this adhesive sheet, and printed circuit board of this metal laminated sheet An object is to provide a wiring board.

As a result of intensive studies, the present inventors have found that a polyimide film adhesive sheet, a metal laminate sheet, and a base film such as an FPC (flexible printed wiring board), TAB tape, and COF tape film, which are regulated to a specific polymer-derived decomposition amount. As a result, it was found that high-quality and uniform FPC (flexible printed wiring board), TAB tape, and COF tape film were obtained, and the present invention was completed.
That is, this invention consists of the following structures.
1. The base film is a polyimide film obtained by reacting aromatic diamines and aromatic tetracarboxylic acids, and is an adhesive sheet in which a thermoplastic adhesive layer is formed on at least one side of the base film, An adhesive sheet, wherein the amount of a polymer-derived decomposition product in the adhesive sheet is 0.01 ppm or more and 8 ppm or less.
2. 1. The aromatic tetracarboxylic acid is pyromellitic acid, and the aromatic diamine is a diamine having a benzoxazole skeleton. Adhesive sheet.
3. 1. The aromatic tetracarboxylic acid is at least one selected from pyromellitic acid and biphenyltetracarboxylic acid, and the aromatic diamine is at least one selected from p-phenylenediamine and diaminodiphenyl ether. Adhesive sheet.
4). 1. The thermoplastic adhesive is a polyimide resin having a glass transition temperature of 380 ° C. or lower. ~ 3. Adhesive sheet.
5. 1 above. ~ 4. A metal laminated sheet comprising a metal foil laminated on the thermoplastic adhesive layer side of any one of the adhesive sheets.
6). 5. above. A printed wiring board, wherein a circuit pattern is formed by partially removing a metal foil of the metal laminate sheet.
7). 6. above. A multilayer printed wiring board, wherein a plurality of printed wiring boards are stacked.
8). 6. above. Or 7. A printed wiring board comprising a semiconductor chip mounted on any printed wiring board.
9. A polyimide film obtained by reacting an aromatic diamine having a polymer-derived decomposition product of 0.01 ppm or more and 10 ppm or less and an aromatic tetracarboxylic acid is used as a base film, and heat is applied to at least one side of the base film. A method for producing an adhesive sheet, comprising forming a plastic adhesive layer and producing an adhesive sheet having a polymer-derived decomposition product content of 0.01 ppm or more and 8 ppm or less.
10. A polyimide precursor layer serving as a thermoplastic adhesive was provided on one or both sides of a polyimide precursor film serving as a substrate film of an adhesive sheet formed by forming a thermoplastic adhesive layer on at least one surface of the substrate film. The manufacturing method of the adhesive sheet characterized by manufacturing the adhesive sheet whose polymer-derived decomposition product amount is 0.01 ppm or more and 8 ppm or less by performing an imidation reaction process later.

The adhesive sheet, metal laminate sheet, and printed wiring board using the polyimide film in the present invention as a base film, for example, in a printed wiring board, a metal foil layer is formed on one or both sides of the polyimide film adhesive sheet. An unnecessary portion of the foil layer is removed to form a wiring pattern having a line width of 1.5 to 30 μm, a line spacing of 1.5 to 30 μm, and a thickness of about 0.3 to 40 μm, for example.
The heat treatment at the time of laminating this metal foil layer affects the base film, and the physical properties of the polyimide film, especially the amount of the decomposition product derived from the polymer of the film during the various treatments and use at a high temperature, as a result, the polymer derived from the adhesive sheet When the amount of decomposed product is within a certain range, the polyimide film and adhesive sheet do not cause product deterioration due to dielectric breakdown or peeling due to volatilization of the polymer-derived decomposed product with respect to these high-temperature treatments. The quality of printed wiring boards, etc. is improved, and the yield is also improved. Products that maintain flatness against high-temperature treatments such as annealing and soldering that these printed wiring boards undergo, and are also subject to dielectric breakdown and peeling. The yield of these products is improved without causing deterioration.
In this way, the polyimide film as a heat resistant film is often exposed to heat, and the amount of degradation product derived from the polymer of the film and the amount of degradation product derived from the polymer of the adhesive sheet with respect to the heat is used for a substrate of an industrial product. It becomes extremely important quality.
The specific adhesive sheet, the metal laminate sheet and the printed wiring board using the specific polyimide film of the present invention are used as electronic parts exposed to high temperatures, and the base material is less likely to warp or distort during the production. It does not cause product deterioration due to dielectric breakdown or peeling due to volatilization of the decomposition products derived from it, and it is possible to produce high-quality electronic components and improve yield, which is extremely significant in industry.

The polyimide film as the base film in the adhesive sheet of the present invention is composed of aromatic diamines (diamines, amide bond salts and derivatives thereof, hereinafter also referred to as aromatic diamines) and aromatic tetracarboxylic acids (acids, anhydrides, A polyimide film obtained by reacting with an amide bond derivative or the like, hereinafter also referred to as an aromatic tetracarboxylic acid), and a polyimide film in which the amount of decomposition product derived from the polymer in the polyimide film is 0.01 ppm or more and 10 ppm or less, In addition, the adhesive sheet is not particularly limited as long as the amount of polymer-derived decomposition product is 0.01 ppm or more and 8 ppm or less, but preferably the following aromatic diamines and aromatic tetracarboxylic acids (anhydrides). A combination with a class is a preferred example.
(1) A combination of an aromatic diamine having a benzoxazole structure and pyromellitic acid, (2) a combination of paraphenylenediamine and pyromellitic acid, (3) a combination of diaminodiphenyl ether and pyromellitic acid, ( 4) Combination of paraphenylenediamine, diaminodiphenyl ether and pyromellitic acid, (5) Combination of paraphenylenediamine and biphenyltetracarboxylic acid, (6) Paraphenylenediamine, diaminodiphenyl ether and biphenyltetracarboxylic acid, pyromellitic acid and The combination of is preferable.
Examples of the aromatic diamine having a benzoxazole structure in (1) that can be preferably used in the present invention include the following compounds.

これらのジアミンは、単独で用いてもよいし、二種以上を併用してもよい。

These diamines may be used alone or in combination of two or more.

In the present invention, the following aromatic diamines may be used without being limited to the above matters. Preferably, the diamines exemplified below are used singly or in combination as long as it is less than 30 mol% of the total diamines. May be.
Examples of such diamines include 4,4′-bis (3-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, and bis [4- (3-aminophenoxy) phenyl]. Sulfide, bis [4- (3-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, m-phenylenediamine, o-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine,

3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfoxide, 3,4′-diaminodiphenyl sulfoxide, 4,4′-diaminodiphenyl Sulfoxide, 3,3′-diaminodiphenylsulfone, 3,4′-diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfone, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′- Diaminobenzophenone, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, bis [4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- ( 4-aminophenoxy) pheny ] Ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane, 1,1-bis [4- (4-aminophenoxy) phenyl] propane, 1,2-bis [4- (4- Aminophenoxy) phenyl] propane, 1,3-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane,

1,1-bis [4- (4-aminophenoxy) phenyl] butane, 1,3-bis [4- (4-aminophenoxy) phenyl] butane, 1,4-bis [4- (4-aminophenoxy) Phenyl] butane, 2,2-bis [4- (4-aminophenoxy) phenyl] butane, 2,3-bis [4- (4-aminophenoxy) phenyl] butane, 2- [4- (4-aminophenoxy) Phenyl] -2- [4- (4-aminophenoxy) -3-methylphenyl] propane, 2,2-bis [4- (4-aminophenoxy) -3-methylphenyl] propane, 2- [4- ( 4-aminophenoxy) phenyl] -2- [4- (4-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2-bis [4- (4-aminophenoxy) -3,5-dimethylphen Le] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane,

1,4-bis (3-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) ) Biphenyl, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfoxide, bis [4- ( 4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 1,3-bis [4- (4-aminophenoxy) ) Benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,4-bis [4- (3 Aminophenoxy) benzoyl] benzene, 4,4′-bis [(3-aminophenoxy) benzoyl] benzene, 1,1-bis [4- (3-aminophenoxy) phenyl] propane, 1,3-bis [4- (3-aminophenoxy) phenyl] propane, 3,4'-diaminodiphenyl sulfide,

2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, bis [4- (3-aminophenoxy) phenyl] methane, 1,1 -Bis [4- (3-aminophenoxy) phenyl] ethane, 1,2-bis [4- (3-aminophenoxy) phenyl] ethane, bis [4- (3-aminophenoxy) phenyl] sulfoxide, 4,4 '-Bis [3- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4'-bis [3- (3-aminophenoxy) benzoyl] diphenyl ether, 4,4'-bis [4- (4-amino-α) , Α-dimethylbenzyl) phenoxy] benzophenone, 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] diphenylsulfone, bis 4- {4- (4-aminophenoxy) phenoxy} phenyl] sulfone, 1,4-bis [4- (4-aminophenoxy) phenoxy-α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) phenoxy-α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-trifluoromethylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3 -Bis [4- (4-amino-6-fluorophenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-methylphenoxy) -α, α-dimethylbenzyl Benzene, 1,3-bis [4- (4-amino-6-cyanophenoxy) -α, α-dimethylbenzyl] benzene,

3,3′-diamino-4,4′-diphenoxybenzophenone, 4,4′-diamino-5,5′-diphenoxybenzophenone, 3,4′-diamino-4,5′-diphenoxybenzophenone, 3, 3'-diamino-4-phenoxybenzophenone, 4,4'-diamino-5-phenoxybenzophenone, 3,4'-diamino-4-phenoxybenzophenone, 3,4'-diamino-5'-phenoxybenzophenone, 3,3 '-Diamino-4,4'-dibiphenoxybenzophenone, 4,4'-diamino-5,5'-dibiphenoxybenzophenone, 3,4'-diamino-4,5'-dibiphenoxybenzophenone, 3,3'- Diamino-4-biphenoxybenzophenone, 4,4′-diamino-5-biphenoxybenzophenone, 3,4 -Diamino-4-biphenoxybenzophenone, 3,4'-diamino-5'-biphenoxybenzophenone, 1,3-bis (3-amino-4-phenoxybenzoyl) benzene, 1,4-bis (3-amino- 4-phenoxybenzoyl) benzene, 1,3-bis (4-amino-5-phenoxybenzoyl) benzene, 1,4-bis (4-amino-5-phenoxybenzoyl) benzene, 1,3-bis (3-amino) -4-biphenoxybenzoyl) benzene, 1,4-bis (3-amino-4-biphenoxybenzoyl) benzene, 1,3-bis (4-amino-5-biphenoxybenzoyl) benzene, 1,4-bis (4-Amino-5-biphenoxybenzoyl) benzene, 2,6-bis [4- (4-amino-α, α-dimethylbenzyl) pheno Si] A part or all of the hydrogen atoms on the aromatic ring in the benzonitrile and the aromatic diamine are halogen atoms, alkyl groups having 1 to 3 carbon atoms or alkoxyl groups, cyano groups, or alkyl groups or alkoxyl group hydrogen atoms. Examples thereof include aromatic diamines substituted with a halogenated alkyl group having 1 to 3 carbon atoms, partially or entirely substituted with halogen atoms, or alkoxyl groups.

  The aromatic tetracarboxylic acids used in the present invention are, for example, aromatic tetracarboxylic anhydrides. Specific examples of the aromatic tetracarboxylic acid anhydrides include the following. Of these, pyromellitic acid of Chemical formula 5 and biphenyltetracarboxylic acid of Chemical formula 6 can be preferably used, and at least one of these is preferably used by 70 mol% or more of the total aromatic tetracarboxylic acids.

  In the present invention, a tetracarboxylic acid other than Chemical Formula 5 or Chemical Formula 6 or a tetracarboxylic dianhydride may be used as long as it is less than 30 mol% of the total tetracarboxylic acid. One or more aromatic tetracarboxylic dianhydrides may be used in combination. Examples of such tetracarboxylic acid anhydrides include butane-1,2,3,4-tetracarboxylic dianhydride, pentane-1,2,4,5-tetracarboxylic dianhydride, and cyclobutanetetracarboxylic acid. Acid dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, cyclohex-1-ene-2,3 5,6-tetracarboxylic dianhydride, 3-ethylcyclohex-1-ene-3- (1,2), 5,6-tetracarboxylic dianhydride, 1-methyl-3-ethylcyclohexane-3 -(1,2), 5,6-tetracarboxylic dianhydride, 1-methyl-3-ethylcyclohex-1-ene-3- (1,2), 5,6-tetracarboxylic dianhydride 1-ethylcyclohexane -(1,2), 3,4-tetracarboxylic dianhydride, 1-propylcyclohexane-1- (2,3), 3,4-tetracarboxylic dianhydride, 1,3-dipropylcyclohexane- 1- (2,3), 3- (2,3) -tetracarboxylic dianhydride, dicyclohexyl-3,4,3 ′, 4′-tetracarboxylic dianhydride,

Bicyclo [2.2.1] heptane-2,3,5,6-tetracarboxylic dianhydride, 1-propylcyclohexane-1- (2,3), 3,4-tetracarboxylic dianhydride, 1 , 3-Dipropylcyclohexane-1- (2,3), 3- (2,3) -tetracarboxylic dianhydride, dicyclohexyl-3,4,3 ′, 4′-tetracarboxylic dianhydride, bicyclo [2.2.1] Heptane-2,3,5,6-tetracarboxylic dianhydride, bicyclo [2.2.2] octane-2,3,5,6-tetracarboxylic dianhydride, bicyclo [2.2.2] Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride and the like. These tetracarboxylic dianhydrides may be used alone or in combination of two or more.

  The solvent used when the polyamic acid is obtained by reacting (polycondensing) the aromatic diamines with the aromatic tetracarboxylic acids is any solvent that dissolves both the monomer as a raw material and the polyamic acid to be produced. Although not particularly limited, polar organic solvents are preferred, such as N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, Examples thereof include dimethyl sulfoxide, hexamethylphosphoric amide, ethyl cellosolve acetate, diethylene glycol dimethyl ether, sulfolane, and halogenated phenols. These solvents can be used alone or in combination. The amount of the solvent used may be an amount sufficient to dissolve the monomer as a raw material. As a specific amount used, the mass of the monomer in the solution in which the monomer is dissolved is usually 5 to 40% by mass, The amount is preferably 10 to 30% by mass.

The polymerization reaction conditions for obtaining the polyamic acid may be conventionally known conditions. As a specific example, stirring and / or continuous in an organic solvent at a temperature range of 0 to 80 ° C. for 10 minutes to 30 hours. Mixing may be mentioned. If necessary, the polymerization reaction may be divided or the temperature may be increased or decreased. In this case, the order of adding both monomers is not particularly limited, but it is preferable to add aromatic tetracarboxylic acid anhydrides to the solution of aromatic diamines. The mass of the polyamic acid in the polyamic acid solution obtained by the polymerization reaction is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, and the viscosity of the solution is measured with a Brookfield viscometer (25 ° C.). From the viewpoint of the stability of liquid feeding, it is preferably 10 to 2000 Pa · s, and more preferably 100 to 1000 Pa · s. The reduced viscosity (ηsp / C) of the polyamic acid in the present invention is not particularly limited, but is preferably 3.0 dl / g or more, and more preferably 4.0 dl / g or more.
Vacuum defoaming during the polymerization reaction is effective for producing a high-quality polyamic acid organic solvent solution. Moreover, you may perform superposition | polymerization by adding a small amount of terminal blockers to aromatic diamines before a polymerization reaction. Examples of the end capping agent include compounds having a carbon-carbon double bond such as maleic anhydride. The amount of maleic anhydride used is preferably 0.001 to 1.0 mol per mol of aromatic diamine.

  As an imidization method by high-temperature treatment, a conventionally known imidation reaction can be appropriately used. For example, using a polyamic acid solution that does not contain a ring-closing catalyst or a dehydrating agent, the imidization reaction proceeds by subjecting it to a heat treatment (so-called thermal ring-closing method), or a polycyclic acid solution containing a ring-closing catalyst and a dehydrating agent. In particular, a chemical ring closing method in which an imidization reaction is performed by the action of the above ring closing catalyst and a dehydrating agent can be given.

In the chemical ring closure method, imidation can be completely performed by heating after forming a precursor complex having self-supporting property by partially proceeding imidization reaction of the polyamic acid solution.
In this case, the condition for partially proceeding with the imidization reaction is preferably a heat treatment for 3 to 20 minutes at 100 to 200 ° C., and the condition for allowing the imidization reaction to be completely performed is preferably 200 to 400 ° C. For 3 to 20 minutes.
The timing for adding the ring-closing catalyst to the polyamic acid solution is not particularly limited, and may be added in advance before the polymerization reaction for obtaining the polyamic acid. Specific examples of the ring-closing catalyst include aliphatic tertiary amines such as trimethylamine and triethylamine, and heterocyclic tertiary amines such as isoquinoline, pyridine, and betapicoline. Among them, heterocyclic tertiary amines are mentioned. At least one amine selected from is preferred. Although the usage-amount of a ring-closing catalyst with respect to 1 mol of polyamic acids does not have limitation in particular, Preferably it is 0.5-8 mol.
The timing of adding the dehydrating agent to the polyamic acid solution is not particularly limited, and may be added in advance before the polymerization reaction for obtaining the polyamic acid. Specific examples of the dehydrating agent include aliphatic carboxylic acid anhydrides such as acetic anhydride, propionic anhydride, butyric anhydride, and aromatic carboxylic acid anhydrides such as benzoic anhydride. Among them, acetic anhydride, benzoic anhydride, etc. Acids or mixtures thereof are preferred. Moreover, the usage-amount of the dehydrating agent with respect to 1 mol of polyamic acids is not particularly limited, but is preferably 0.1 to 4 mol. When a dehydrating agent is used, a gelation retarder such as acetylacetone may be used in combination.

The polyamic acid solution is cast and dried on a support to obtain a green film (a self-supporting polyamic acid solution film, also referred to as a polyimide precursor film). When the green film is dried to the extent that self-supporting properties are obtained, the residual solvent amount of the polyimide film obtained by the subsequent imidization is controlled within a predetermined range by controlling the residual solvent amount relative to the total mass after drying. An unimpaired polyimide film can be obtained. Specifically, it is important that the residual solvent amount with respect to the total mass after drying is preferably 25 to 50% by mass.
When the residual solvent amount is lower than 25% by mass, drying of one side of the green film proceeds excessively, and it becomes difficult to obtain a green film having a small difference in the degree of drying between the front and back surfaces. Green film tends to be brittle. Moreover, when it exceeds 50 mass%, self-supporting property becomes inadequate and conveyance of a film becomes difficult in many cases.
In order to achieve such conditions, a drying apparatus such as hot air, hot nitrogen, far infrared rays, and high frequency induction heating can be used, but the following temperature control is required as the drying conditions.
When performing hot air drying, when drying the green film to the extent that self-supporting properties are obtained, in order to make the range of the dryness of the green film front and back surfaces and the difference between them, the constant rate drying condition is lengthened, It is preferable to operate so that the solvent volatilizes uniformly from the entire coating film. Constant rate drying is a drying region in which the coating film surface is a free liquid surface and the volatilization of the solvent is governed by mass transfer in the outside world. Under the drying conditions where the coating surface is dried and solidified and the solvent diffusion within the coating is rate-limiting, the physical property difference between the front and back surfaces is likely to occur. The preferable dry state varies depending on the type and thickness of the support, but the temperature setting, the air flow setting, and the atmospheric temperature above the coating film (green film) on the support (green film side) are usually higher. The coating film is dried under the condition that the ambient temperature on the opposite side (opposite side of the coating film side) is 1 to 55 ° C. higher. In the description of the atmospheric temperature, the direction is defined with the direction from the coating film toward the support being the downward direction and the opposite being the upward direction. Such a description in the vertical direction is made for concisely expressing the position of the region to be noted, and is not for specifying the absolute direction of the coating film in actual production.

The “atmosphere temperature on the coating film side” is a temperature in a region (usually a space) from directly above the coating film to 30 mm on the coating film side, and a temperature at a position 5 to 30 mm away from the coating film in the upward direction. By measuring with a thermocouple or the like, the ambient temperature on the coating film surface side can be determined.
“Atmosphere temperature on the opposite side” is the temperature in the region (often including the support and the lower part of the support) from directly below the coating (support part) to the lower 30 mm of the coating. By measuring the temperature at a position 5 to 30 mm downward from the membrane with a thermocouple or the like, the atmosphere temperature on the opposite side can be obtained.
If the atmospheric temperature on the opposite surface side is 1 to 55 ° C. higher than the atmospheric temperature on the coating film side during drying, a high-quality film can be obtained even if the drying temperature is increased and the drying speed of the coating film is increased. Can do. If the atmospheric temperature on the opposite surface side is lower than the atmospheric temperature on the coating surface side, or if the difference between the atmospheric temperature on the coating surface side and the atmospheric temperature on the opposite side is less than 1 ° C., the vicinity of the coating surface is first There is a concern that the film may be dried into a film to form a “lid”, and thereafter, the evaporation of the solvent to be evaporated from the vicinity of the support is hindered, and the internal structure of the film is distorted. It is undesirable for the apparatus and the economy to be disadvantageous in that the atmospheric temperature on the opposite side is higher than the atmospheric temperature on the coating film side and the temperature difference is greater than 55 ° C. Preferably, at the time of drying, the ambient temperature on the opposite side is higher by 10 to 50 ° C., more preferably 15 to 45 ° C. than the ambient temperature on the coating film side.
The setting and management of such drying conditions require more rigorous setting and management in the case of a thin polyimide film of about 1 μm to 15 μm in terms of the amount of decomposed polymer derived from the resulting polyimide polymer and physical properties.
The setting of the atmospheric temperature as described above may be performed over the entire process of drying the coating film, or may be performed in a part of the process of drying the coating film. When the coating film is dried by a continuous dryer such as a tunnel furnace, the above-mentioned atmospheric temperature may be set in the drying effective length, preferably 10 to 100%, more preferably 15 to 100%. .
The drying time is 10 to 90 minutes in total, desirably 15 to 45 minutes.

The green film that has undergone the drying step is then subjected to an imidization step, but may be either inline or off-line.
When the off-line is adopted, the green film is wound up once. At this time, curling can be reduced by winding the green film on the tubular body so that the green film is on the inner side (the support is on the outer side).
In any case, it is preferable to carry or wind the film so that the radius of curvature does not become 30 mm or less.
The amount of degradation product derived from the polymer of the present invention is obtained by imidizing a green film obtained by such a method with the dryness of the front and back surfaces (residual solvent amount) and the difference thereof controlled within a predetermined range under predetermined conditions. Is obtained in a predetermined range.
As a specific imidization method, a conventionally known imidation reaction can be appropriately used. For example, using a polyamic acid solution that does not contain a ring-closing catalyst or a dehydrating agent, the imidization reaction proceeds by subjecting it to a heat treatment (so-called thermal ring-closing method), or a polycyclic acid solution containing a ring-closing catalyst and a dehydrating agent. In order to obtain a polyimide film or a polyimide long film as a preferred base film of the present invention, a chemical ring closure method in which an imidization reaction is performed by the action of the ring closure catalyst and the dehydrating agent can be given. Thermal ring closure is preferred.

In order to keep the amount of the polymer degradation product contained in the adhesive sheet within the predetermined range in the present invention, after the heat treatment of the polyimide film, the film coming out of the heat treatment furnace is not immediately wound, and both surfaces of the film are made free. It is preferable to wind up after holding in the atmosphere or inert gas for 5 minutes or more, preferably 7 minutes or more, more preferably 10 minutes or more, and still more preferably 16 minutes or more. The double-sided free state means a state where the film is in direct contact with the atmosphere or an inert gas. Of course, a film can be conveyed in the meantime using a plurality of rolls or the like. If the retention time is short enough to secure enough time for the low molecular weight substances contained in the film to be discharged out of the film by diffusion, the low molecular weight substances such as polymer-derived degradation products, solvents, and reaction byproducts remain. The amount may increase. On the other hand, if the time is too long, film handling is difficult and productivity may be reduced.
In addition, in the present invention, after forming a thermoplastic adhesive layer on the polyimide film surface to form an adhesive sheet, the both surfaces of the film are left free for 3 minutes or more, preferably 5 minutes or more, more preferably It is preferable to wind up after being kept in the atmosphere or inert gas for 7 minutes or more, more preferably 11 minutes or more.

  Further, in the present invention, the surface of the polyimide film or adhesive sheet is subjected to ultrasonic waves in the air or inert gas, preferably broadband ultrasonic waves of 30 kHz to 250 kHz, and further the air or imperfections near the film or adhesive sheet surface. It is preferable to update the surface of the active gas at a flow rate of 0.5 m / second or more, preferably 3 m / second or more, more preferably 15 m / second or more, and still more preferably 30 m / second. When this treatment is performed on the polyimide film, it is preferably performed within 5 minutes, preferably within 7 minutes, more preferably within 15 minutes immediately after leaving the heat treatment furnace. Such treatment is to prevent low molecular weight substances, including polymer-derived decomposition products, present in the vicinity of the film in the heat treatment furnace from adhering to the film surface due to cooling condensation. Similarly, this treatment is preferably performed after forming a thermoplastic adhesive layer on the polyimide film surface to obtain an adhesive sheet.

In the present invention, the polymer-derived degradation amount of the polyimide film used as the base film is preferably 0.01 ppm to 10 ppm, more preferably 0.01 ppm to 8 ppm, and still more preferably 0.01 ppm to 5 ppm. The following is preferable, but the smaller the amount, the better. However, considering the ease of production, cost, etc., it is sufficient that the defect does not substantially occur. The lower limit is specifically 0.01 ppm. .
In the present invention, the “amount of polymer-derived decomposition product” was measured as follows.
Using a Curie point thermal decomposition apparatus, the polymer degradation product amount was determined by GCMS method. A sample (standard 4 mg) is precisely weighed on a 500 ° C pyrofoil manufactured by Nihon Analytical Industries (heated and dried) in advance (the weighing value is A (mg)), and the temperature inside the thermal decomposition apparatus is set to 170 ° C. Sample foil was introduced and helium purged for 3 minutes. Immediately thereafter, heating was performed at 500 ° C. for 10 seconds by an oscillation operation. Polymer degradation products volatilized from the film during the 10 second heating at 500 ° C. were detected by GCMS. The total ion (TIC) peak area was determined, and the polymer degradation product amount B (μg) was determined by an absolute calibration curve method in terms of aniline. The polymer degradation product amount with respect to the polyimide film was calculated by the following equation.
Polymer degradation product amount (ppm) = B (μg) / A (mg) × 1000
(Pyrolysis GCMS conditions)
Device: HP5973N (HPMS GCMS)
JHS-3 (Nippon Analytical Industrial Pyrolysis System)
Column: HP-1 (manufactured by Agilent Technologies),
0.25mmφ × 25m, film thickness 1μm
Column temperature: 40 ° C./2 min hold → Temperature rise to 260 ° C. at 10 ° C./min→at 260 ° C.
Hold for 5 minutes Flow rate: He 0.7 ml / min, split introduction Mass operation range: m / z = 30 to 550

The polymer-derived decomposition product in the present invention is considered to decompose and volatilize from the polyimide film mainly under such an atmosphere in accordance with the above measurement conditions, and has a molecular weight of 90 to 200 and one or more molecular skeletons. It is a polymer-derived decomposition product having a nitrogen atom.
Such polymer-derived decomposition products are represented by the following compounds, and include at least one of them.
Aniline, benzonitrile, 1-methyl-2,5-pyrrolidinedione, methylisocyanobenzene, 1,2-benzodinitrile, dimethylbenzamide, 2-methylisoindole-1,3-dione, 4-cyanophenylglyoxal 1-oxime.
The method for obtaining a polyimide film in which the amount of polymer-derived decomposition products with respect to the polyimide film is within a predetermined range is not particularly limited, but is carried out by selecting the drying conditions and high-temperature imidation conditions for the green film precursor of the polyimide film. As a drying condition for obtaining a green film, for example, when N, N-dimethylacetamide is used as a solvent, the drying temperature is preferably 70 to 130 ° C., more preferably 80 to 130 ° C. It is 125 degreeC, More preferably, it is 85-120 degreeC. When this drying temperature is higher than 130 ° C., the molecular weight is lowered, and the green film tends to be brittle. In addition, imidization partially proceeds during the production of the green film, and it becomes difficult to obtain desired physical properties during the imidization process. On the other hand, when the temperature is lower than 70 ° C., the drying time becomes long, the molecular weight tends to decrease, and the handling property tends to be poor due to insufficient drying. Further, the drying time is preferably 5 to 90 minutes, more preferably 15 to 80 minutes, although it depends on the drying temperature. When the drying time is longer than 90 minutes, the molecular weight is lowered and the film tends to be fragile. When the drying time is shorter than 5 minutes, the handling property tends to be poor due to insufficient drying.
A conventionally known drying apparatus can be applied, and examples thereof include hot air, hot nitrogen, far infrared rays, and high frequency induction heating.

By imidizing the obtained green film under predetermined conditions, a polyimide film having a polymer-derived decomposition product content of 0.01 ppm or more and 10 ppm or less can be obtained.
As a specific method of imidization, a conventionally known imidation reaction and imidization treatment can be appropriately used. Preferably, the pretreatment temperature of the green film is 130 ° C. or higher and 150 ° C. or lower, and 3 minutes. Pretreatment of the green film for a time of 15 minutes or less and a maximum imidization reaction treatment temperature of 480 ° C. or more and less than 500 ° C., and a high temperature imidation treatment is preferably performed for a time of 3 minutes or more and 30 minutes or less. .
The thicknesses of the polyimide film and the polyimide benzoxazole film are not particularly limited, but are usually 1 to 250 μm, preferably 1 to 25 μm, more preferably 3 to 10 μm in consideration of use for a base substrate for a printed wiring board. This thickness can be easily controlled by the amount of the polyamic acid solution applied to the support and the concentration of the polyamic acid solution.
The polyimide film of the present invention is usually an unstretched film, but may be stretched uniaxially or biaxially. Here, the unstretched film refers to a film obtained without intentionally applying a mechanical external force in the surface expansion direction of the film by tenter stretching, roll stretching, inflation stretching, or the like.

In the adhesive sheet of the present invention, the amount of the decomposition product derived from the polymer of the base film is preferably a polyimide film having a content of 0.01 ppm or more and 10 ppm or less as the base material. In the adhesive sheet, on the at least one side of the base film. A thermoplastic adhesive layer is formed and laminated, and in a metal laminated sheet, a metal laminated sheet in which a metal foil is laminated on the thermoplastic adhesive layer side, in a printed wiring board, a metal laminated sheet, A printed wiring board with a circuit pattern formed by etching away unnecessary portions of metal foil, and a multilayer printed wiring board in which a plurality of printed wiring boards are stacked, and a semiconductor chip mounted directly on these printed wiring boards It has been done.
Furthermore, the adhesive sheet of the present invention can be used for forming an insulating layer between printed wiring boards.

The thermoplastic adhesive used in the present invention is not particularly limited as long as it is thermoplastic or thermocompression-bonded and has excellent heat resistance and adhesiveness. It is preferable to be smaller than the tensile modulus of the material. The tensile modulus of the adhesive / the tensile modulus of the substrate (ratio of the tensile modulus) is preferably 0.01 to 0.5, more preferably 0.3 or less, and particularly preferably 0.1 or less.
If the tensile modulus of the thermoplastic adhesive is higher than that of the base film, the stress strain of the base film and the metal foil having a different linear expansion coefficient cannot be relaxed and absorbed by the adhesive layer. Since connection reliability with the foil layer is not expressed, it is not preferable.
In the present invention, thermoplastic polyimide, polyamideimide, wholly aromatic polyester, polyetherimide, and polyamide resin can be preferably used as the thermoplastic adhesive.
As a preferable thermoplastic adhesive in the present invention, an adhesive from a thermoplastic (thermocompression bonding) polyimide resin is particularly preferable from the viewpoint of heat resistance and adhesion to a polyimide film, and thermoplastic (thermocompression bonding) polyimide. The thermoplastic resin may be any thermoplastic polyimide resin that can be thermocompression bonded at a temperature of about 200 ° C. to 400 ° C.
The Tg (glass transition temperature) of the thermoplastic adhesive forming the thermoplastic adhesive layer is preferably 380 ° C. or less, but the Tg (glass transition temperature) of the thermoplastic adhesive forming the thermoplastic adhesive layer. Is preferably 220 ° C to 350 ° C, more preferably 230 ° C to 340 ° C. When Tg (glass transition temperature) is less than 220 ° C., there is almost no solder heat resistance, and when it exceeds 380 ° C., the adhesiveness is remarkably lowered.
As such a thermocompression bonding polyimide, preferably, as diamines,
APB: 1,3-bis (3-aminophenoxybenzene), 1,3-bis (4-
Aminophenoxybenzene),
m-BP: 4,4′-bis (3-aminophenoxy) biphenyl,
DABP: 3,3′-diaminobenzophenone,
DANPG: 1,3-bis (4-aminophenoxy) -2,2-dimethylpropane,
As at least one diamine selected from: tetracarboxylic anhydride,
PMDA: pyromellitic dianhydride,
ODPS: 3,3 ′, 4,4′-diphenyl ether tetracarboxylic dianhydride,
BTDA: 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride,
BPDA: 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride α-BPDA: 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride,
ODPA: 4,4′-oxydiphthalic dianhydride,
Polyimide obtained from at least one tetracarboxylic dianhydride selected from can be used. These can be used alone or in combination of two or more. Further, other diamines or tetracarboxylic acid anhydrides exemplified above can be used in combination within the range not exceeding 50 mol% of each of the diamines or tetracarboxylic acid anhydrides.

In the present invention, a polyimide obtained from 1,3-bis (4-aminophenoxybenzene) and 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, preferably 1,3-bis (4- A polyimide obtained from aminophenoxybenzene) and pyromellitic dianhydride, 1,3-bis (4-aminophenoxy) -2,2-dimethylpropane and 4,4′-oxydiphthalic dianhydride (ODPA); A polyimide prepared from 1,4'-oxydiphthalic dianhydride (ODPA) and pyromellitic dianhydride and 1,3-bis (4-aminophenoxybenzene), Polyimide obtained from bis (3-aminophenoxy) benzene and 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3′-diaminobenzo Examples thereof include a polyimide obtained from phenone and 1,3-bis (3-aminophenoxy) benzene and 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride.
The reaction molar ratio of the diamine component and the tetracarboxylic dianhydride is usually in the range of 0.75 to 1.25 mol of the tetracarboxylic dianhydride component with respect to 1 mol of the diamine component. Preferably it is the range of 0.8-1.2 mol.

In the present invention, a dicarboxylic anhydride may be added for the purpose of sealing the polymer terminal of the thermoplastic polyimide related to the thermoplastic polyimide layer as the thermoplastic adhesive. Examples of the dicarboxylic anhydride used include phthalic anhydride, 2,3-benzophenone dicarboxylic anhydride, 3,4-benzophenone dicarboxylic anhydride, 2,3-dicarboxyphenyl phenyl ether anhydride, 2,3- Biphenyl dicarboxylic acid anhydride, 3,4-biphenyl dicarboxylic acid anhydride, 2,3-dicarboxyphenyl phenyl sulfone anhydride, 3,4-dicarboxyphenyl phenyl sulfone anhydride, 2,3-dicarboxyphenyl phenyl sulfide anhydrous 1,2-naphthalene dicarboxylic acid anhydride, 2,3-naphthalene dicarboxylic acid anhydride, 1,8-naphthalene dicarboxylic acid anhydride, 1,2-anthracene dicarboxylic acid anhydride, 2,3-anthracene dicarboxylic acid Examples include acid anhydrides and 1,9-anthracene dicarboxylic acid anhydrides.
These dicarboxylic acid anhydrides may be substituted with groups that are not reactive with amines or dicarboxylic acid anhydrides. The addition amount of the dicarboxylic acid anhydride is usually in the range of 0.001 to 0.5 mol with respect to 100 mol of the total amount of the specific diamine and tetracarboxylic dianhydride as the main raw materials. Preferably, it is the range of 0.005-0.25 mol.

  Similarly, a monoamine may be added for the purpose of sealing the polymer terminal of the thermoplastic polyimide. Examples of the monoamine used include aniline, o-toluidine, m-toluidine, p-toluidine, 2,3-xylidine, 2,4-xylidine, 2,5-xylidine, 2,6-xylidine, 3,4 -Xylidine, 3,5-xylidine, o-chloroaniline, m-chloroaniline, p-chloroaniline, o-nitroaniline, o-bromoaniline, m-bromoaniline, o-nitroaniline, m-nitroaniline, p -Nitroaniline, o-aminophenol, m-aminophenol, p-aminophenol, o-anilysine, m-anilysine, p-anilysine, o-phenetidine, m-phenetidine, p-phenetidine, o-aminobenzaldehyde, m -Aminobenzaldehyde, p-aminobenzaldehyde, o-aminobenzonitrile Ril, m-aminobenzonitrile, p-aminobenzonitrile, 2-aminobiphenyl, 3-aminobiphenyl, 4-aminobiphenyl, 2-aminophenol phenyl ether, 3-aminophenol phenyl ether, 4-aminophenol phenyl ether, 2-aminobenzophenone, 3-aminobenzophenone, 4-aminobenzophenone, 2-aminophenol phenyl sulfide, 3-aminophenol phenyl sulfide, 4-aminophenol phenyl sulfide, 2-aminophenol phenyl sulfone, 3-aminophenol phenyl sulfone, 4-aminophenol phenyl sulfone, α-naphthylamine, β-naphthylamine, 1-amino-2-naphthol, 2-amino-1-naphthol, 4-amino-1-naphth 5-amino-1-naphthol, 5-amino-1-naphthol, 5-amino-2-naphthol, 7-amino-2-naphthol, 8-amino-2-naphthol, 1-aminoanthracene, 2- Examples include aminoanthracene and 9-aminoanthracene.

These monoamines may be used alone or in combination of two or more. The amount of monoamine added is usually in the range of 0.001 to 0.5 mol with respect to a total of 100 mol of the specific diamine and tetracarboxylic dianhydride as the main raw materials. Preferably it is the range of 0.005-0.25 mol.
In addition, a polyamideimide resin, a polyetherimide resin, a polyesterimide resin, or the like can be used alone or in appropriate combination as long as the conditions are satisfied.
In addition, as long as the advantages of the present invention are not impaired, a thermosetting adhesive such as an epoxy-based or cyanate-based adhesive may be mixed with the thermoplastic adhesive of the present invention, and this thermosetting in the entire adhesive layer. The proportion of adhesive is at most 40%.
The thermoplastic polyimide resin reacts with the above components, and optionally other tetracarboxylic dianhydrides and other diamines in an organic solvent at a temperature of about 100 ° C. or less, particularly 20 to 60 ° C. Thus, a polyamic acid solution can be prepared, and the polyamic acid solution can be used as a dope solution.
Also, the polyamic acid solution produced as described above is heated to 150 to 250 ° C., or an imidizing agent is added and reacted at a temperature of 150 ° C. or less, particularly 15 to 50 ° C., to imide cyclization. Thereafter, the solvent is evaporated or precipitated in a poor solvent to form a powder, and then the powder is dissolved in an organic solution to obtain an organic solvent solution of a thermocompression-bondable polyimide resin.

In order to obtain the thermoplastic polyimide resin in the present invention, the amount of diamine (as the number of moles of amino group) used in the organic solvent is the total number of moles of acid anhydride (tetraacid dianhydride and dicarboxylic acid anhydride). Ratio of the product to the total moles as acid anhydride groups) is preferably from 0.92 to 1.1, in particular from 0.98 to 1.1, in particular from 0.99 to 1.1. The ratio of the amount of acid anhydride used is preferably 0.05 or less, particularly preferably 0.02 or less, as the ratio of the amount of acid anhydride to the molar amount of acid anhydride group of tetracarboxylic dianhydride. .
When the ratio of the diamine and dicarboxylic acid anhydride is out of the above range, the resulting polyamic acid, and hence the thermoplastic polyimide, has a low molecular weight, resulting in a decrease in the adhesive strength of the flexible metal foil laminate. Further, for the purpose of limiting the gelation of the polyamic acid, a phosphorus stabilizer such as triphenyl phosphite and triphenyl phosphate is 0.01 to 1% by mass with respect to the solid content (polymer) concentration during polyamic acid polymerization. It can be added in the range of. For the purpose of promoting imidization, a basic organic compound catalyst can be added to the dope solution.
For example, imidazole, 2-imidazole, 1,2-dimethylimidazole, 2-phenylimidazole and the like can be used at a ratio of 0.05 to 10% by mass, particularly 0.1 to 2% by mass with respect to the polyamic acid. . Since these form a polyimide film at a relatively low temperature, they are used to avoid imidation becoming insufficient. For the purpose of stabilizing the adhesive strength, an organoaluminum compound, an inorganic aluminum compound, or an organotin compound may be added to the thermocompression bonding polyimide raw material dope. For example, aluminum hydroxide, aluminum triacetylacetonate or the like can be added in an amount of 1 ppm or more, particularly 1 to 1000 ppm as aluminum metal with respect to polyamic acid.

The organic solvent used for the production of the polyamic acid is N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethyl for both high heat-resistant polyimide and thermocompression bonding polyimide. Examples include acetamide, N, N-diethylacetamide, dimethyl sulfoxide, hexamethylphosphoramide, N-methylcaprolactam, and cresols. These organic solvents may be used alone or in combination of two or more.
Note that plasma treatment, corona treatment, and alkali treatment of the polyimide film surface before applying (laminating) the thermoplastic adhesive is a preferable method for increasing the adhesive force, and such plasma is an inert gas plasma. As the inert gas, nitrogen gas, Ne, Ar, Kr, or Xe is used. There is no particular limitation on the method for generating plasma, and an inert gas may be introduced into the plasma generator to generate plasma.
The time required for the plasma treatment is not particularly limited, and is usually 1 second to 30 minutes, preferably 10 seconds to 10 minutes. There are no particular restrictions on the frequency and output of the plasma during the plasma processing, the gas pressure for generating the plasma, and the processing temperature as long as they can be handled by the plasma processing apparatus. The frequency is usually 13.56 MHz, the output is usually 50 W to 1000 W, the gas pressure is usually 0.01 Pa to 10 Pa, and the temperature is usually 20 ° C. to 250 ° C., preferably 20 ° C. to 180 ° C. If the output is too high, the substrate film surface may crack. Moreover, when gas pressure is too high, there exists a possibility that the smoothness of the base film surface may fall.

Next, a thermoplastic adhesive layer is formed on the surface-treated polyimide film surface, but the method is not limited, but a thermoplastic adhesive layer is applied to the polyimide film surface and dried to apply the thermoplastic adhesive layer. Form a thermoplastic adhesive layer on the polyimide film surface by forming a thermoplastic adhesive layer in advance on the release film or film and pasting or transferring it to the polyimide film surface. The method etc. are mentioned as a preferable example.
Among them, the polymer-derived decomposition product amount is obtained by laminating a polyimide precursor film layer serving as a thermoplastic adhesive on one side or both sides of a film comprising a polyimide precursor serving as a base film, and then performing an imidization reaction treatment. A method for producing an adhesive sheet having a concentration of 0.01 ppm or more and 8 ppm or less can be preferably summarized.
Specific methods for providing a polyimide precursor film layer as a thermoplastic adhesive on one or both sides of a polyimide precursor film as a base film include direct coating and drying, thermoplastic polyimide Examples thereof include: / base film layer / thermoplastic polyimide, a method of sequentially laminating and coating each precursor, and a method of pressure laminating each precursor film prepared in advance. In the case of pressure lamination, it is preferable to bond at a temperature below room temperature.
The thickness of the thermoplastic adhesive layer is preferably 0.5 or less (1.0 or less in the case of both surfaces) with respect to the thickness of the base polyimide film to be used, more preferably 0.3. The following thickness (in the case of both sides, 0.6 or less).
In the adhesive sheet in which these thermoplastic adhesive layers are formed on at least one surface of the base polyimide film, the amount of polymer-derived degradation product measured by the method for measuring the amount of degradation product derived from the polymer is 0.01 ppm or more and 8 ppm or less. In other words, it is essential that the amount of polymer-derived decomposition products contained in the thermoplastic adhesive layer and the base polyimide film is 0.01 ppm or more and 8 ppm or less. The amount of polymer-derived decomposition products contained in the adhesive sheet, that is, the thermoplastic adhesive layer and the base polyimide film is more preferably 0.01 ppm to 5 ppm, and still more preferably 0.01 ppm to 3 ppm.

In the lamination of the metal foil, the metal foil is laminated on the thermoplastic adhesive layer formed on the polyimide film surface with or without the plasma treatment, and laminated using pressure, heat, or the like.
The metal as the metal foil of the present invention is silver, copper, gold, platinum, rhodium, nickel, aluminum, iron, chromium, zinc, tin, brass, bronze, bronze, monel, tin lead solder, tin copper solder, Tin-silver solder or the like alone or an alloy thereof is used, but using copper is a preferred embodiment in terms of balance between performance and economy. When the metal foil layer is used for a circuit (conductive), the thickness of the metal layer is preferably 1 to 175 μm, more preferably 3 to 50 μm. When using the polyimide film which bonded the metal foil layer as a heat sink, the thickness of a metal layer becomes like this. Preferably it is 50-3000 micrometers.
Although the surface roughness of the polyimide film surface laminated via the thermoplastic adhesive layer of the metal foil layer is not particularly limited, the centerline average roughness in JIS B 0601 (definition and display of surface roughness) ( It is preferable that the values expressed by Ra) and 10-point average roughness (hereinafter Rz) are 0.1 μm or less for Ra and 1.0 μm or less for Rz.
In this invention, it is a preferable aspect that the metal laminated sheet which is a composite_body | complex of the polyimide film and metal foil obtained by the said method is further heat-processed at 200-350 degreeC. This heat treatment is preferably 220 to 330 ° C, more preferably 240 to 310 ° C. The heat treatment reduces the strain of the base film and the strain generated in the manufacturing process of the metalized polyimide film, and can more effectively express the effects of the present invention. And reliability can be improved. If it is less than 200 ° C., the effect of alleviating the strain becomes small. Conversely, if it exceeds 350 ° C., the polyimide film of the base material deteriorates, which is not preferable.

The thus obtained metal laminated sheet of the present invention is coated with a photoresist on the side of a conductive metal foil layer or a later thick film metal layer formed on the conductive metal foil layer, if necessary. After drying, a wiring circuit pattern is formed by the steps of exposure, development, etching, and photoresist stripping. Furthermore, solder resist coating, plastic and electroless tin plating are performed as necessary, and flexible printed wiring boards are multilayered. A multilayer printed wiring board or a printed wiring board on which a semiconductor chip is directly mounted can be obtained. There are no particular limitations on the method for producing these circuits, making them multi-layered, and mounting a semiconductor chip, and the methods may be appropriately selected from conventionally known methods.
On the surface of the metal (foil) layer used in the present invention or, if necessary, the thick film metal layer attached later, an inorganic coating such as a single metal or a metal oxide may be formed. Good. In addition, the surface of the metal foil layer or the post-attached thick film metal layer formed on the metal foil layer, if necessary, is treated with a coupling agent (aminosilane, epoxysilane, etc.), sand plast treatment, rolling treatment, corona treatment, You may use for a plasma process, an etching process, etc.

  Examples of the present invention will be described below, but the present invention is not limited thereto. In addition, the evaluation method of the physical property in the following examples is as follows except for the above.

1. Reduced viscosity of polyamic acid (ηsp / C)
A solution dissolved in N-methyl-2-pyrrolidone so that the polymer concentration was 0.2 g / dl was measured at 30 ° C. using an Ubbelohde type viscosity tube.

2. Film thickness of polyimide film The thickness of the film was measured using a micrometer (Finereuf, Millitron 1254D).

Abbreviations of compounds used in Examples and the like are described below.
PMDA: pyromellitic dianhydride ODA: 4,4′-diaminodiphenyl ether P-PDA: paraphenylenediamine BPDA: 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride DMF: dimethylformamide DMAC: dimethyl Acetamide AA: Acetic anhydride IQ: Isoquinoline Abbreviation GF indicates a polyimide precursor film (green film), and abbreviation IF indicates a polyimide film.

<Preparation of polyamic acid solution (1)>
The inside of a reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, and then 300 parts by mass of 5-amino-2- (p-aminophenyl) benzoxazole (p-DAMBO) was charged. Next, 4400 parts by mass of DMAC was added and completely dissolved, and then 300 parts by mass of pyromellitic dianhydride was added and stirred at a reaction temperature of 25 ° C. for 17 hours, whereby a brown and viscous polyamic acid solution (1) was obtained. Obtained. Ηsp / C of this product was 4.1 dl / g.

<Production of Film 1 to Film 6)
The obtained polyamic acid solution (1) was coated on a surface not containing a lubricant of a polyester film (Cosmo Shine A4100 (manufactured by Toyobo Co., Ltd.)) having a thickness of 188 μm and a width of 800 mm (squeegee / belt). The gaps were varied depending on the resulting film thickness) and dried through a continuous drying oven with four drying zones. Each zone has three rows of slit-shaped air outlets above and below the film. The hot air temperature between the air outlets can be controlled within a range of plus or minus 1.5 ° C and the air volume difference can be controlled within a range of plus or minus 3%. Has been. The width direction is controlled to be within ± 1 ° C. until a width corresponding to 1.2 times the effective film width.
The setting of the drying oven is as follows.
Leveling zone temperature 25 ° C, no air volume 1st zone upper temperature 105 ° C, lower temperature 105 ° C
Air volume 20-25 cubic m / min for both top and bottom Zone 2 Upper temperature 100 ° C, Lower temperature 100 ° C
Air volume 30 to 35 cubic m / min in both upper and lower zones Third zone Upper temperature 95 ° C, Lower temperature 100 ° C
Air volume 20-25 cubic m / min on both top and bottom Zone 4 Upper temperature 90 ° C, Lower temperature 100 ° C
Upper air volume 15-18 cubic m / min, lower air volume 20-25 cubic m / min The length of each zone is the same.
The air volume is the total of the air volumes from the outlets of each zone, and the production of the polyamic acid film (GF) of Films 1 to 6 was changed within the above range.
In addition, it is confirmed that the temperature is within ± 1.5 ° C. by monitoring at intervals of 10 cm by a thermocouple supported at a position of 10 mm on the film at the portion directly below the blowout port at the center of each zone.
The polyamic acid film (GF) that became self-supporting after drying was peeled from the polyester film to obtain each GF. The values of the residual solvent amount in each GF were 35%, 37%, 38%, and 36%, respectively. 37% and 38%.
Each of the obtained GFs was provided with a brush made of an aromatic polyamide monofilament strand so as to be in contact with both ends of the film, and continuously substituted with nitrogen in a state where both ends of the film were evenly stabbed into the pins of the pin tenter. The first stage is heated at 180 ° C. for 5 minutes, and the heating rate is 4 ° C./second, and the second stage is heated at 500 ° C. for 5 minutes for 2 minutes under the condition of imide The reaction was allowed to proceed. The film that came out of the heat treatment furnace was cooled to about room temperature over about 3 minutes, and further conveyed in the atmosphere adjusted to a cleanness of 1000 or less for 5 minutes. After that, the film width direction is film width +40 mm, and the film traveling direction is irradiated with broadband ultrasonic waves of 30 kHz to 150 kHz in the section of 50 mm, and the air flow is controlled so that the flow velocity is 30 m / sec at the boundary of the same area. The atmosphere near the film surface was updated. After the film is further conveyed for 2 minutes, the film is neutralized with an ion-type static eliminator so that the surface potential is 0.3 kV or less, wound up in a roll on a 6-inch plastic core having a static eliminating capability, and brown. Films 1 to 6 which are each IF (polyimide film) to be obtained were obtained.
The thickness of each IF obtained and the amount of polymer-derived decomposition products were 5.0 μm and 2.5 ppm for film 1, 7.5 μm and 2.0 ppm for film 2, 12.5 μm and 0.5 ppm for film 3, The film 4 was 25 μm and 0.4 ppm, the film 5 was 33 μm and 0.3 ppm, and the film 6 was 50 μm and 3.2 ppm.

<Production of Film 1b to Film 6b)
In the same manner as Films 1 to 6, the polyamic acid solution (1) thus obtained was 188 mm thick and 780 mm wide on a polyester film (Cosmo Shine A4100 (manufactured by Toyobo Co., Ltd.)) having a thickness of 188 μm and no width. (The squeegee / belt gap was varied depending on the resulting film thickness) and dried through a continuous drying oven with four drying zones. The setting of the drying oven is as follows.
Leveling zone temperature 25 ° C, no air volume 1st zone upper temperature 105 ° C, lower temperature 105 ° C
Air volume 20-25 cubic m / min for both top and bottom Zone 2 Upper temperature 100 ° C, Lower temperature 100 ° C
Air volume 30 to 35 cubic m / min on both top and bottom Zone 3 Upper temperature 95 ° C, Lower temperature 95 ° C
Air volume 20-25 cubic m / min for both top and bottom Zone 4 Upper side temperature 90 ° C, Lower side temperature 90 ° C
Air volume 20-25 cubic m / min in both top and bottom The length of each zone is the same.
Also, the air volume is the total of the air volumes from the outlets of each zone, and the production of the polyamic acid film (GF) of the films 7 to 9 is changed within the above range.
In addition, it is confirmed that the temperature is within ± 1.5 ° C. by monitoring at intervals of 10 cm by a thermocouple supported at a position of 10 mm on the film at the portion directly below the blowout port at the center of each zone.
The polyamic acid film (GF) that became self-supporting after drying was peeled from the polyester film to obtain each GF. The values of the residual solvent amount in each GF were 48%, 47%, 49%, and 48%, respectively. 47% and 48%.
Each of the obtained GFs was provided with a brush made of an aromatic polyamide monofilament strand so as to be in contact with both ends of the film, and continuously substituted with nitrogen in a state where both ends of the film were evenly stabbed into the pins of the pin tenter. The first stage is heated at 180 ° C. for 5 minutes, and the heating rate is 4 ° C./second, and the second stage is heated at 500 ° C. for 5 minutes for 2 minutes under the condition of imide The reaction was allowed to proceed. Then, imidation was advanced by cooling to room temperature in 5 minutes. Then, the film 1b-the film 6b which are each IF (polyimide film) which exhibits brown were obtained by cooling to room temperature in 5 minutes.
The thickness of each IF obtained and the amount of polymer-derived decomposition products are 5.0 μm and 19.5 ppm for film 1b, 7.5 μm and 18.0 ppm for film 2b, 12.5 μm and 13.5 ppm for film 3b, film It was 25 μm and 12.0 ppm for 4b, 33 μm and 10.5 ppm for film 5b, and 50 μm and 22.5 ppm for film 6b.
Contrary to expectations, when a polyimide film was produced under conditions similar to the conventional method without any new device, the thin film had a higher rate of polymer-derived decomposition products than the thicker film, and the appearance was judged. There were many inferior things.

<Preparation of polyamic acid solution (2)>
A container equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, and then ODA was added. Next, after adding DMAC and completely dissolving it, PMDA is added, and ODA and PMDA as monomers are polymerized in DMAC at a molar ratio of 1/1 so that the monomer charge concentration becomes 15% by mass. After stirring at 25 ° C. for 5 hours, a brown viscous polyamic acid solution (2) was obtained. ηsp / C was 2.1 dl / g.

<Preparation of Film 7 to Film 10)
The obtained polyamic acid solution (2) was coated on a surface not containing a lubricant of a polyester film (Cosmo Shine A4100 (manufactured by Toyobo Co., Ltd.)) having a thickness of 188 μm and a width of 800 mm (squeegee / belt). The gaps were varied depending on the resulting film thickness) and dried through a continuous drying oven with four drying zones. Each zone has three rows of slit-shaped air outlets above and below the film. The hot air temperature between the air outlets can be controlled within a range of plus or minus 1.5 ° C and the air volume difference can be controlled within a range of plus or minus 3%. Has been. The width direction is controlled to be within ± 1 ° C. until a width corresponding to 1.2 times the effective film width.
The setting of the drying oven is as follows.
Leveling zone temperature 25 ° C, no air volume 1st zone upper temperature 105 ° C, lower temperature 105 ° C
Air volume 20-25 cubic m / min for both top and bottom Zone 2 Upper temperature 100 ° C, Lower temperature 100 ° C
Air volume 30 to 35 cubic m / min in both upper and lower zones Third zone Upper temperature 95 ° C, Lower temperature 100 ° C
Air volume 20-25 cubic m / min on both top and bottom Zone 4 Upper temperature 90 ° C, Lower temperature 100 ° C
Upper air volume 15-18 cubic m / min, lower air volume 20-25 cubic m / min The length of each zone is the same.
The air volume is the total of the air volumes from the outlets of each zone, and the production of the polyamic acid film (GF) of Films 1 to 6 was changed within the above range.
In addition, it is confirmed that the temperature is within ± 1.5 ° C. by monitoring at intervals of 10 cm by a thermocouple supported at a position of 10 mm on the film at the portion directly below the blowout port at the center of each zone.
The polyamic acid film (GF) that became self-supporting after drying was peeled from the polyester film to obtain each GF. The residual solvent amount values of each GF were 35%, 37%, 38%, and 36%, respectively. there were.
Each of the obtained GFs was provided with a brush made of an aromatic polyamide monofilament strand so as to be in contact with both ends of the film, and continuously substituted with nitrogen in a state where both ends of the film were evenly stabbed into the pins of the pin tenter. The first stage is heated at 180 ° C. for 5 minutes, and the heating rate is 4 ° C./second, and the second stage is heated at 500 ° C. for 5 minutes for 2 minutes under the condition of imide The reaction was allowed to proceed. The film that came out of the heat treatment furnace was cooled to about room temperature over about 3 minutes, and further conveyed in the atmosphere adjusted to a cleanness of 1000 or less for 5 minutes. After that, the film width direction is film width +40 mm, and the film traveling direction is irradiated with broadband ultrasonic waves of 30 kHz to 150 kHz in the section of 50 mm, and the air flow is controlled so that the flow velocity is 30 m / sec at the boundary of the same area. The atmosphere near the film surface was updated. After the film is further conveyed for 2 minutes, the film is neutralized with an ion-type static eliminator so that the surface potential is 0.3 kV or less, wound up in a roll on a 6-inch plastic core having a static eliminating capability, and brown. Films 7 to 10 which are each IF (polyimide film) to be obtained were obtained.
The thickness of each IF obtained and the amount of polymer-derived decomposition products were 5.0 μm and 5.8 ppm for film 7, 7.5 μm and 6.0 ppm for film 8, 12.5 μm and 4.5 ppm for film 9, and film 10 was 25 μm and 3.5 ppm.

<Production of Film 7b to Film 10b)
Using the polyamic acid solution (2), films 7b to 10b were produced in the same manner as in the production conditions of films 1b to 6b.
The thickness of each IF obtained and the amount of polymer-derived decomposition products were 5.0 μm and 21.8 ppm for film 7b, 7.5 μm and 19.0 ppm for film 8b, 12.5 μm and 18.5 ppm for film 9b, film It was 25 micrometers and 13.6 ppm in 10b.

<Preparation of polyamic acid solution (3)>
PMDA and BPDA are used as aromatic tetracarboxylic dianhydride components, and four types of monomers, ODA and P-PDA, are used as diamine components, and PMDA / BPDA / ODA / P-PDA is 1 / 0.5 / 1/0. A polyamic acid solution (3) was prepared by polymerizing in DMF at a molar ratio of 0.5 so that the monomer charge concentration was 16% by mass.

<Production of Film 11 to Film 12)
Each GF was obtained in the same manner as Film 7 to Film 10 except that the polyamic acid solution (3) was coated on the stainless steel belt.
The thickness of each IF obtained and the amount of polymer-derived decomposition products were 10 μm and 3.0 ppm for film 11 and 25 μm and 1.7 ppm for film 12.

<Production of Film 11b to Film 12b)
Using the polyamic acid solution (3), films 11b to 12b were produced in the same manner as in the production conditions of films 1b to 6b.
The amount of degradation product derived from the thickness polymer of each IF obtained was 10 μm and 22.5 ppm for the film 11b and 25 μm and 11.0 ppm for the film 12b.

<Preparation of polyamic acid solution (4)>
In DMAC, ODA was supplied at 60 mol% based on the total diamine and dissolved, and then P-PDA (40 mol%) and PMDA were sequentially supplied, and stirred at room temperature for about 1 hour. Finally, a solution having a polyamic acid concentration of 20% by mass comprising a tetracarboxylic dianhydride component and a diamine component having a stoichiometry of about 100 mol% was prepared. This polyamic acid solution was ice-cooled, acetic anhydride and β-picoline were added and stirred to obtain a polyamic acid solution (4).

<Preparation of Film 13 to Film 15>
Each GF was obtained in the same manner as in Film 7 to Film 10 except that the polyamic acid solution (4) was coated on a stainless steel belt.
The thickness of each IF obtained and the amount of polymer-derived decomposition products were 10 μm and 3.6 ppm for film 13, 25 μm and 1.5 ppm for film 14, and 50 μm and 5.1 ppm for film 15, respectively.

<Production of Film 13b to Film 15b)
Using the polyamic acid solution (4), films 13b to 15b were produced in the same manner as in the production conditions of films 1b to 6b.
The amount of degradation product derived from the thickness polymer of each IF obtained was 10 μm and 23.5 ppm for the film 13b, 25 μm and 16.8 ppm for the film 14b, and 50 μm and 22.1 ppm for the film 15b.

<Preparation of polyamic acid solution (5)>
A container equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, and then P-PDA was added. Next, after DMAC is added and completely dissolved, BPDA is added, and P-PDA and BPDA as monomers are polymerized in DMAC at a molar ratio of 1/1, and the monomer charge concentration becomes 15% by mass. Thus, when stirred at 25 ° C. for 5 hours, a brown viscous polyamic acid solution (5) was obtained.

<Production of Film 16 to Film 18>
Each GF was obtained in the same manner as Film 7 to Film 10 except that the polyamic acid solution (5) was coated on the stainless steel belt.
The thickness of each IF obtained and the amount of polymer-derived decomposition products were 7.5 μm and 3.3 ppm for film 16, 12.5 μm and 1.2 ppm for film 17, and 25 μm and 0.6 ppm for film 18.

<Production of Film 16b to Film 18b)
Using the polyamic acid solution (5), films 16b to 18b were produced in the same manner as in the production conditions of films 1b to 6b.
The thickness of each IF obtained and the amount of polymer-derived decomposition products were 7.5 μm and 23.5 ppm for film 16b, 12.5 μm and 11.4 ppm for film 17b, and 25 μm and 10.7 ppm for film 18b.

<Preparation of polyamic acid solution (6)>
A container equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, and then P-PDA was added. Next, DMAC is added and completely dissolved, then PMDA is added, and P-PDA and PMDA as monomers are polymerized in DMAC at a molar ratio of 1/1, and the monomer charge concentration becomes 15% by mass. Thus, when stirred at 25 ° C. for 5 hours, a brown viscous polyamic acid solution (6) was obtained.

<Production of Film 19 to Film 20>
Each IF was obtained in the same manner as in Film 7 to Film 10 except that the polyamic acid solution (6) was coated on the stainless steel belt.
The amount of degradation product derived from the thickness polymer of each IF obtained was 12.5 μm and 4.2 ppm for film 19 and 25 μm and 1.3 ppm for film 20.

<Production of Film 19b to Film 20b)
Using the polyamic acid solution (6), films 16b to 18b were produced in the same manner as in the production conditions of films 1b to 6b.
The amount of degradation product derived from the thickness polymer of each IF obtained was 12.5 μm and 17.9 ppm for the film 19b, and 25 μm and 13.0 ppm for the film 20b.

(Examples 1-40, Comparative Examples 1-40)
<Manufacture of adhesive sheet>
Using each polyimide film obtained in each production example, an adhesive sheet was obtained according to the following.
<Production of polyamic acid solution for thermoplastic polyimide for adhesive>
N-methyl-2-pyrrolidone is added to a reaction vessel equipped with a stirrer and a nitrogen introduction tube, and 1,3-bis (4-aminophenoxy) benzene and 2,3,3 ′, 4′-biphenyltetracarboxylic acid are added. Acid dianhydride was added at a molar ratio of 1000: 1000 so that the monomer concentration was 22% by mass, and triphenyl phosphate was added at 0.1% by mass with respect to the monomer mass. After completion of the addition, the reaction was continued for 1 hour while maintaining 25 ° C. to obtain a polyamic acid (SA1) solution. Ηsp / C of the obtained polyamic acid was 1.6 dl / g. (The Tg of the thermoplastic polyimide as the adhesive was 340 ° C.)
Using this SA1, a double coater was applied to one side of the polyimide film in each production example so as to have a dry thickness of 7 μm, dried at 90 ° C. for 30 minutes, and the dried film was continuously formed. Each heat which was passed through a heat treatment furnace and was heated almost linearly from 200 ° C. to 380 ° C. in 20 minutes and then cooled to room temperature, and each polyimide film was provided with thermoplastic polyimide having a thickness of 3 μm on one side. Each single-sided adhesive sheet which is a pressure-bondable multilayer polyimide film was obtained.
Tables 1 and 2 show the amounts of polymer-derived decomposition products of the obtained adhesive sheets.

Similarly, this SA1 was applied to both sides of each polyimide film obtained in each production example with a double coater so as to have a dry thickness of 7 μm, dried at 90 ° C. for 30 minutes, and dried film. Was passed through a continuous heat treatment furnace, and heated from 200 ° C. to 380 ° C. almost linearly in 20 minutes and cooled in 10 minutes. A thermoplastic polyimide having a thickness of 3 μm was disposed on both sides of each polyimide film. Each double-sided adhesive sheet which is each thermocompression-bonding multilayer polyimide film was obtained. The total thickness of the polyimide film and adhesive layer of each obtained double-sided adhesive sheet was 6 μm.
Tables 3 and 4 show the amounts of polymer-derived decomposition products of the obtained adhesive sheets.

<Manufacture of metal laminate sheet>
The roll surface temperature was heated to 240 ° C. by heating using a thermocompression bonding machine of a roll internal heating and external heating combined method. A double-sided adhesive sheet (thermocompression-bonding multilayer polyimide film) obtained between the rolls is passed, and peelable copper foil with an ultrathin copper foil layer of 3 μm and a support copper foil layer of 30 μm is supplied and laminated from both sides. The support copper foil layer was peeled off to obtain each double-sided metal laminate sheet from each polyimide film consisting of copper foil / heat-sealable multilayer polyimide film / copper foil.

<Manufacture of printed wiring boards>
A liquid crystal resist is used to form a negative resist with a film thickness of 3 μm on one side of each double-sided metal laminate sheet produced above, the copper layer is removed by etching, and an LCD including fine lines with line spacing / line width of 20 μm / 15 μm A test circuit pattern of 4.8 cm × 4.8 cm assumed to be mounted on a driver was formed. Similarly, a square pattern of 4 mm square was formed in a lattice shape with a pattern spacing of 0.5 mm on the back surface, and a large number of test circuit boards from each polyimide film were produced in the same manner. The area density of the pattern is 50% on both the front and back sides. Prepare three test circuit boards, and use each film and each adhesive sheet of the same production example between each test circuit board and each test circuit board. Each single-sided adhesive sheet of the same production example as each of the films used was arranged on the top and bottom so as to be made of the same polyimide film, and laminated by thermocompression bonding to prepare each test multilayer substrate.
In each test multilayer substrate of each polyimide film 1 to film 20, there was no pattern peeling, but in each test multilayer substrate from the polyimide film of film 1 b to film 20 b, pattern peeling was seen. It was often done.
In addition, for cross-sectional observation, each test multilayer substrate is cut in the direction in which the cross-section in the width direction of the fine line pattern comes out, embedded with resin, end-face polished, and then magnified with a microscope, and there is no deformation of the adhesive sheet In each of the test multilayer substrates from the polyimide films of each of the polyimide films 1 to 20, the adhesive sheet was not deformed and there was no abnormal part of the circuit, but the films 1b to 20b In each of the test multilayer substrates from the polyimide film, deformation of the adhesive sheet was observed, and a part peeled from the circuit film was observed.

(Example 41, Comparative Example 41)
<Manufacture of adhesive sheet>
<Production of polyamic acid solution for thermoplastic polyimide for adhesive>
A vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, and then m-phenylenebis (oxy-p-phenylene) diamine was added. Next, DMAC is added and completely dissolved, and then 4,4′-oxydiphthalic dianhydride is added to form m-phenylenebis (oxy-p-phenylene) diamine and 4,4′-oxydiphthalic acid as monomers. When dianhydride was polymerized in DMAC at a molar ratio of 1/1, the monomer charge concentration was 15% by mass, and stirred at 25 ° C. for 5 hours, a brown viscous polyamic acid solution (SA2) was gotten. (The Tg of the thermoplastic polyimide as the adhesive was 280 ° C.)
A polyamic acid solution (SA2) is coated on a surface not containing a lubricant of a polyester film (Cosmo Shine A4100 (manufactured by Toyobo Co., Ltd.)) having a thickness of 188 μm and a width of 800 mm so as to have a dry film thickness of 6 μm and a width of 550 mm. It dried by passing through the continuous drying furnace which has four drying zones. Each zone has three rows of slit-shaped air outlets above and below the film. The hot air temperature between the air outlets can be controlled within a range of plus or minus 1.5 ° C and the air volume difference can be controlled within a range of plus or minus 3%. Has been. The width direction is controlled to be within ± 1 ° C. until a width corresponding to 1.2 times the effective film width.
The setting of the drying oven is as follows.
Leveling zone temperature 25 ° C, no air volume 1st zone upper temperature 105 ° C, lower temperature 105 ° C
Air volume 20-25 cubic m / min for both top and bottom Zone 2 Upper temperature 100 ° C, Lower temperature 100 ° C
Air volume 30 to 35 cubic m / min in both upper and lower zones Third zone Upper temperature 95 ° C, Lower temperature 100 ° C
Air volume 20-25 cubic m / min on both top and bottom Zone 4 Upper temperature 90 ° C, Lower temperature 100 ° C
Upper air volume 15-18 cubic m / min, lower air volume 20-25 cubic m / min The length of each zone is the same.
The air volume is the total of the air volumes from the outlets of each zone, and the production of Example 41 was changed within the above range.
In addition, it is confirmed that the temperature is within ± 1.5 ° C. by monitoring at intervals of 10 cm by a thermocouple supported at a position of 10 mm on the film at the portion directly below the blowout port at the center of each zone.
After drying, the polyamic acid solution (1) was coated on the precursor film layer so as to have a dry film thickness of 20 μm and a width of 740 mm, and dried as described above. Further, the polyamic acid solution (SA2) was then coated so as to have a dry film thickness of 6 μm and a width of 550 mm, and dried in the same manner.
The polyimide precursor film having the three-layer structure obtained as described above is peeled off from the support, and a brush made of an aromatic polyamide monofilament strand is provided so as to be in contact with both ends of the film. The first stage was heated at 180 ° C. for 10 minutes and at a rate of temperature increase of 4 ° C./second, and the second stage was heated to 500 ° C. The imidation reaction was allowed to proceed by applying two stages of heating under the conditions of 10 minutes. The film that came out of the heat treatment furnace was cooled to about room temperature over about 3 minutes, and further conveyed in the atmosphere adjusted to a cleanness of 1000 or less for 5 minutes. After that, the film width direction is film width +40 mm, and the film traveling direction is irradiated with broadband ultrasonic waves of 30 kHz to 150 kHz in the section of 50 mm, and the air flow is controlled so that the flow velocity is 30 m / sec at the boundary of the same area. The atmosphere near the film surface was updated. After the film is further conveyed for 2 minutes, the film is neutralized with an ion-type static eliminator so that the surface potential is 0.3 kV or less, wound on a 6-inch plastic core having a static eliminating capability, and wound on the surface. An adhesive sheet Example 41 having a thermoplastic polyimide layer was obtained.
The obtained adhesive sheet had a total thickness of 16 μm. Moreover, it was confirmed by electron micrograph observation of the cross section that the surface thermoplastic polyimide layer was 3 μm and the center base film was 10 μm. The amount of degradation product derived from the polymer of the obtained film was 2.15 ppm.

The adhesive sheet of Comparative Example 41 was obtained in the same manner as in Example 41 except that the drying conditions were as follows and the film obtained from the heat treatment was immediately wound on a 6-inch core.
Leveling zone temperature 25 ° C, no air volume 1st zone upper temperature 105 ° C, lower temperature 105 ° C
Air volume 20-25 cubic m / min for both top and bottom Zone 2 Upper temperature 100 ° C, Lower temperature 100 ° C
Air volume 30 to 35 cubic m / min on both top and bottom Zone 3 Upper temperature 95 ° C, Lower temperature 95 ° C
Air volume 20-25 cubic m / min for both top and bottom Zone 4 Upper side temperature 90 ° C, Lower side temperature 90 ° C
Air volume 20-25 cubic m / min in both top and bottom The length of each zone is the same.
The amount of polymer-derived decomposition product in the obtained adhesive sheet of Comparative Example 41 was 11.5 ppm.

<Examples 42 to 46, Comparative Examples 42 to 46>
Example 42 to Example are the same as Example 41 and Comparative Example 41 except that the polyamic acid solution (1) serving as the base film is replaced with the polyamic acid solution (2) to the polyamic acid solution (6), respectively. 46, each adhesive sheet of Comparative Examples 42 to 46 was obtained. Table 5 shows the amounts of polymer-derived decomposition products of these adhesive sheets.

<Manufacture of metal laminate sheet>
The roll surface temperature was heated to 240 ° C. by heating using a thermocompression bonding machine of a roll internal heating and external heating combined method. The double-sided adhesive sheets (thermocompression-bonding multilayer polyimide film) of Examples 41 to 46 and Comparative Examples 41 to 46 obtained between the rolls were passed, and from both sides, an ultrathin copper foil layer of 3 μm and support copper Supplying and laminating 30 μm foil layer of peelable copper foil, peeling the support copper foil layer after lamination, laminating each double-sided metal from each polyimide film consisting of copper foil / heat-sealable multilayer polyimide film / copper foil A sheet was obtained.

<Manufacture of printed wiring boards>
A liquid crystal resist is used to form a negative resist with a film thickness of 3 μm on one side of each double-sided metal laminate sheet produced above, the copper layer is removed by etching, and an LCD including fine lines with line spacing / line width of 20 μm / 15 μm A test circuit pattern of 4.8 cm × 4.8 cm assumed to be mounted on a driver was formed. Similarly, a square pattern of 4 mm square was formed in a lattice shape with a pattern spacing of 0.5 mm on the back surface, and a large number of test circuit boards from each polyimide film were produced in the same manner. The area density of the pattern is 50% on both sides.
Prepare three test circuit boards for each test, use each adhesive film in the same production example as each film used between each test circuit board, and the same film as each use film at the top and bottom of each test circuit board. Each single-sided adhesive sheet of the production example is selected and arranged from Examples 1 to 20 and Comparative Examples 1 to 20 from the same base polyimide film of the same thickness, and laminated by thermocompression bonding, Each test multilayer substrate was prepared.
In each of the test multilayer substrates from the adhesive sheets of Examples 41 to 46, all the patterns were not peeled off, but in each of the test multilayer substrates from the adhesive sheets of Comparative Examples 41 to 46 In many cases, peeling of the pattern was observed.
In addition, for cross-sectional observation, each test multilayer substrate is cut in the direction in which the cross-section in the width direction of the fine line pattern comes out, embedded with resin, end-face polished, and then magnified with a microscope, and there is no deformation of the adhesive sheet In each of the test multilayer substrates from the adhesive sheets of Examples 41 to 46, all of the adhesive sheets were not deformed and there was no abnormal part of the circuit. In each test multilayer substrate from the adhesive sheet of Comparative Example 46, deformation of the adhesive sheet was observed, and a part peeled from the circuit film was observed.

As described above, the adhesive sheet, the metal laminate sheet and the printed wiring board using the polyimide film having specific physical properties of the present invention as a base material are excellent in flatness and product yield, for example, Even when processed into a printed wiring board, it is not warped or distorted and has excellent flatness maintenance, and also has excellent abnormalities in the adhesion of the metal foil layer due to flatness maintenance. .
In addition, since uniform lamination processing is performed even when multilayered, it is suitable for display drivers, high-speed arithmetic devices, graphic controllers, high-capacity memory elements, etc. that require warping, small deformation, particularly high-density fine wiring. It is useful as a substrate to be used. In particular, they are useful as printed circuit boards such as display drivers, high-speed arithmetic devices, graphic controllers, and high-capacity memory devices that are often exposed to high temperatures.

Claims (10)

  The base film is a film made of polyimide obtained by reacting aromatic diamines and aromatic tetracarboxylic acids, and an adhesive sheet in which a thermoplastic adhesive layer is formed on at least one side of the base film, The adhesive sheet is characterized in that the amount of polymer-derived decomposition product is 0.01 ppm or more and 8 ppm or less in the adhesive sheet.   The adhesive sheet according to claim 1, wherein the aromatic tetracarboxylic acid is pyromellitic acid and the aromatic diamine is a diamine having a benzoxazole skeleton.   The adhesive sheet according to claim 1, wherein the aromatic tetracarboxylic acid is at least one selected from pyromellitic acid and biphenyltetracarboxylic acid, and the aromatic diamine is at least one selected from p-phenylenediamine and diaminodiphenyl ether.   The adhesive sheet according to claim 1, wherein the thermoplastic adhesive is a polyimide resin having a glass transition temperature of 380 ° C. or lower.   A metal laminated sheet, wherein a metal foil is laminated on the thermoplastic adhesive layer side of the adhesive sheet according to claim 1.   A printed wiring board, wherein a circuit pattern is formed by removing a part of the metal foil of the metal laminated sheet according to claim 5.   A multilayer printed wiring board, wherein a plurality of printed wiring boards according to claim 6 are stacked.   A printed wiring board comprising a semiconductor chip mounted on the printed wiring board according to claim 6.   A polyimide film obtained by reacting an aromatic diamine having a polymer-derived decomposition product of 0.01 ppm or more and 10 ppm or less and an aromatic tetracarboxylic acid is used as a base film, and heat is applied to at least one side of the base film. A method for producing an adhesive sheet, comprising: forming a plastic adhesive layer, and producing an adhesive sheet containing a polymer-derived decomposition product in an amount of 0.01 ppm to 8 ppm.   A polyimide precursor layer serving as a thermoplastic adhesive layer is provided on one or both sides of a polyimide precursor film serving as a substrate film of an adhesive sheet formed by forming a thermoplastic adhesive layer on at least one surface of the substrate film. A method for producing an adhesive sheet comprising producing an adhesive sheet containing a polymer-derived decomposition product of 0.01 ppm or more and 8 ppm or less by performing an imidization reaction treatment after the treatment.