JP2007141877A - Metallization polyimide film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metallization polyimide film excellent in the adhesion of copper foil and a substrate, insulation reliability, and migration resistance, and is adapted to practical use as a substrate of a highly reliable COF, TAB, an FPC, a semiconductor package, or the like. <P>SOLUTION: In a metallization polyimide film formed by laminating (1) a first metal layer not containing Cu, and (2) a second metal layer principally comprising Cu sequentially on at least one side of a polyimide film, the amount of residual metal other than Cu on the surface of the polyimide film treated with a sulphuric acid/hydrogen peroxide based etching reagent after the metallization polyimide film is heat-treated at 150°C is 1 μg/cm<SP>2</SP>or less. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a metal-coated polyimide film used for electronic devices and electronic components that reduce the size and weight of the components. More specifically, the present invention relates to the metal-coated polyimide film for flexible printed wiring boards used in semiconductor packaging, interposer, module substrate, TAB tape, COF, FPC and the like.

  Conventionally, a metal-coated polyimide film used for a so-called three-layer type flexible printed wiring board in which a metal foil such as a copper foil or an aluminum foil is bonded to a polyimide film with an adhesive is known. This has the following problems considered to be caused by the adhesive used. First of all, there are drawbacks in that the dimensional accuracy is deteriorated due to thermal inferior performance than the film, and the electrical characteristics are deteriorated due to impurity ion contamination, and there is a limit to high-density wiring. In addition, there is a drawback that workability such as sulfole drilling for both surfaces is lowered due to the difference in thickness of the adhesive layer and mechanical and thermal characteristics. Therefore, it can be said that there are many inconvenient points for reducing the size and weight.

On the other hand, a metal layer is formed on a polyimide film by a method such as vacuum deposition, sputtering, ion plating, or copper plating without using an adhesive. Metal-coated polyimide films have been proposed. For example, a flexible electric circuit carrier in which a chromium-based ceramic vapor deposition layer, a copper or copper alloy vapor deposition layer, and a copper plating layer are sequentially provided on an insulating film has been proposed (see Patent Document 1).
JP-A-4-329690

In addition, a metal-film laminate manufacturing method has been proposed in which a metal oxide by plasma is randomly arranged on a polymer film, and then a metal vapor deposition layer and a metal plating layer are provided (see Patent Document 2). Further, a chromium / chromium oxide sputtering layer having a thickness of 25 to 150 Å is provided on the electrically insulating support film, and a copper sputtering layer having a thickness of less than 1 micron is applied, and a photoresist composition is applied to the copper layer. A method of manufacturing a circuit material to be applied has been proposed (see Patent Document 3).
JP-A-4-290742 Japanese Patent Application Laid-Open No. Sho 62-293689

In addition, a part or all of the deposited metal is mixed in the film in the thickness direction from the surface of the film to one or both sides of the polyimide film containing 0.02 to 1% by mass of tin in the film. And a first vapor-deposited metal layer having a thickness in the range of 10 to 300 Å including the mixed layer is provided, and then a second vapor-deposited layer made of copper is provided on the vapor-deposited layer. A flexible printed wiring board, wherein the first metal layer is preferably at least one selected from the group of chromium, a chromium alloy and a chromium compound, and the metal constituting the first vapor-deposited metal layer is 20% chromium. A flexible printed wiring board that is less than nichrome is disclosed (see Patent Document 4).
JP-A-8-330728

As can be seen from these examples, the conventional thin film type metal-coated polyimide film is formed by first forming some underlayer on the polyimide film and then forming copper as a good conductive material thereon. . There is no theory about the adhesive force between the metal layer which is a conductive layer and the polyimide film which is a base material, and some combinations of metals are put into practical use in the accumulation of empirical theory. However, they do not necessarily satisfy all the required characteristics.
When a non-metal or metal oxide is used for the underlayer, it is difficult to remove the underlayer by etching, and the metal oxide left between the lines due to the reducing action in the electroless plating process, etc. May be reduced and become a conductive metal foreign matter, resulting in poor insulation between wires. Further, chromium oxide often used as an underlayer is considered to be an unfavorable compound for environmental hygiene.

  When a metal other than copper is used for the underlayer, it becomes a problem whether the underlayer can be removed with a copper etching solution. If a metal having better corrosion resistance than copper is used, the removal of the underlying metal becomes insufficient, and the insulation between the lines may be lowered. In the case of a metal that is easier to etch than copper, the underlying portion is easily over-etched, and the effective adhesive strength of the conductor is likely to be reduced. Furthermore, even if the lowering of the insulation property due to the base metal itself is not a problem, the metal remaining during the electroless plating in the subsequent process shows catalytic activity, and the plated metal may be deposited between the lines to cause a short circuit. is there. Furthermore, there is a concern that the base material remaining between the wirings may deteriorate the migration resistance between the wirings.

A base metal thin film and a copper thin film were formed on one surface of the polyimide film, and the other surface was constituted by a thin film with low oxygen permeability, and a circuit copper layer was provided on one or both surfaces of the polyimide film. Materials for flexible printed circuit boards have been proposed (see Patent Document 5).
The proposal was made from the viewpoint that the decrease in adhesive force is due to the oxidation of the interface between the metal and the polyimide film. However, all the materials with low oxygen permeability exemplified are brittle and have high flexibility. It is unsuitable for the required flexible printed wiring board.
JP-A-6-29634

From this point of view, in recent years, metal-coated polyimide films using a nickel-chromium-based alloy as a base have attracted attention, and a nickel-chromium-based alloy layer is used as a base layer for a general polyimide film and further thickened with copper. There is an example of such a metal-coated film (see, for example, Patent Document 6).
Nickel-chromium alloys are materials that have a relatively high resistance to oxidative embrittlement and can be expected to have an appropriate anchor effect. On the other hand, there is a concern that the metal component tends to remain after etching and the insulation reliability may deteriorate.
JP 2002-252257 A

  In recent years, the demand for high-density wiring in the semiconductor industry has been advanced, and in the above-described advanced semiconductor package for high-density wiring, the above-described conventional technology has reliability such as durability against changes in temperature and humidity in the usage environment. Sex cannot meet market demands.

  In view of such a situation, the present inventors have excellent adhesion between a copper foil and a base material, excellent insulation reliability, migration resistance, and a highly reliable COF, TAB, FPC, semiconductor package substrate, and the like. As a result of continuing research for the purpose of realizing a metal-coated polyimide film that is practical as a material, the inventors have reached the next invention.

That is, the present invention has the following configuration.
[1] A metal-coated polyimide film in which (1) a first metal layer containing no Cu and (2) a second metal layer mainly composed of Cu are sequentially laminated on at least one surface of a polyimide film. After the heat treatment of the polyimide film at 150 ° C., the amount of residual metal other than Cu on the surface of the polyimide film treated with the sulfuric acid / hydrogen peroxide etching reagent is less than 1 μg / square cm and 0 μg / square cm or more. Metal-coated polyimide film.
[2] The metal-coated polyimide film of [1], wherein the polyimide film is a polyimide film obtained by condensation polymerization of a diamine having a benzoxazole skeleton and an aromatic tetracarboxylic dianhydride .
It is.

In the metal-coated polyimide film of the present invention, the so-called base metal layer can be easily removed, the decrease in interfacial adhesion due to oxidative deterioration of the base layer is suppressed, and the durability is improved, and due to changes in heat and humidity Since there are few changes in the form of the base film, it has excellent electrical characteristics, without reducing the etching property and plating resistance of the wiring circuit pattern, and without lowering the adhesive strength even when exposed to prolonged heating, Furthermore, it has excellent migration resistance. Therefore, even in a thin semiconductor package with high-density wiring, durability against changes in temperature and humidity in the usage environment of the semiconductor package is improved, and the reliability of the semiconductor is increased. In the production method of the present invention, the metal-coated polyimide film having the above-described characteristics can be produced stably and economically.
As in the present invention, a method for forming a plurality of types of metal layers on a polyimide film has been widely known. In such a configuration in which a plurality of metal layers are stacked, mutual diffusion of metal components occurs at the dissimilar metal interface. As a result of mutual diffusion, a multi-component alloy or intermetallic compound in contact with the boundary is generated in the vicinity of the interface, so that the solubility with respect to the etching reagent used for circuit formation is changed. The present inventors have found that the chemical and qualitative change of the first metal layer particularly during long-term storage affects the maintenance and durability of the adhesive strength, and the configuration of the metal layer is specified under high temperature acceleration conditions. It has been found that the adhesive strength can be prevented from lowering even in a heat and humidity resistant environment by maintaining the chemical durability of the resin.
In a polyimide film, it is guessed that a very small amount of carboxyl groups and amide groups exist at a level that is difficult to analyze derived from the polyamic acid that is an intermediate thereof. The coexistence of water with these amphoteric functional groups creates an electrochemical potential between adjacent dissimilar metal components, causing electrochemical corrosion over a long period of time, and this phenomenon is the adhesion between the metal layer and the polyimide layer. It is thought that it reduces.
The sulfuric acid / hydrogen peroxide etching reagent used in the present invention is known to have relatively high etching selectivity to Cu, but has etching properties for metals other than Cu, particularly base metals, The chemical durability of the metal component can be known from the etching property with respect to such a reagent. Here, it is known that chemical durability depends not only on chemical redox reaction but also on passive components formed on the surface of the metal layer. The inventors of the present invention have chemical durability after a high-temperature acceleration test, that is, formation of a passive component causes stress between the polyimide film and the underlying metal layer, thereby reducing adhesiveness. However, it is considered that it triggers migration that impairs the insulation reliability between wirings electrochemically, and the state of passive components is quantified in the form of resistance to a specific etching reagent. Configured.
Furthermore, normally, when a Ni—Cr base metal layer is used, a processing chemical dedicated to the base metal is required. However, in the present invention, a normal circuit is formed with a normal Cu etching solution. Is possible.

  Hereinafter, embodiments of the metal-coated polyimide film of the present invention and the manufacturing method thereof will be described in detail. The metal-coated polyimide film of the present invention comprises a polyimide film, a first metal layer, a second metal layer, and a thick metal layer formed as necessary.

Hereinafter, the polyimide film in the present invention will be described. The polyimide film is a film made of a polymer compound having an imide bond in the main chain. A polyimide film is generally obtained by polycondensation of diamines and tetracarboxylic dianhydrides.
The reaction between an aromatic diamine for obtaining a polyimide film, which can be preferably applied to the present invention, and an aromatic tetracarboxylic acid is carried out by reacting an aromatic diamine and an aromatic tetracarboxylic acid (anhydride) in a solvent. (Ring-opening) A polyamic acid solution that is a polyimide precursor is obtained by polyaddition reaction, and then a precursor film (also called a green film) is formed from this polyamic acid solution, followed by drying, heat treatment, and dehydration condensation. It is manufactured by (imidization).

Although the polyimide film in this invention is not specifically limited, The combination of the following aromatic diamine and aromatic tetracarboxylic acid (anhydride) is mentioned as a preferable example.
A. A combination of an aromatic diamine having a benzoxazole structure and an aromatic tetracarboxylic acid.
B. A combination of an aromatic diamine having a diaminodiphenyl ether skeleton and an aromatic tetracarboxylic acid having a pyromellitic acid skeleton.
C. A combination of an aromatic diamine having a phenylenediamine skeleton and an aromatic tetracarboxylic acid having a biphenyltetracarboxylic acid skeleton.
D. A combination of one or more of the above ABCs.
Examples of aromatic diamines having a benzoxazole structure that can be preferably used in the present invention include the following compounds.

  2,2′-p-phenylenebis (5-aminobenzoxazole), 2,2′-p-phenylenebis (6-aminobenzoxazole), 1- (5-aminobenzoxazolo) -4- (6- Aminobenzoxazolo) benzene, 2,6- (4,4′-diaminodiphenyl) benzo [1,2-d: 5,4-d ′] bisoxazole, 2,6- (4,4′-diaminodiphenyl) ) Benzo [1,2-d: 4,5-d ′] bisoxazole, 2,6- (3,4′-diaminodiphenyl) benzo [1,2-d: 5,4-d ′] bisoxazole, 2,6- (3,4'-diaminodiphenyl) benzo [1,2-d: 4,5-d '] bisoxazole, 2,6- (3,3'-diaminodiphenyl) benzo [1,2- d: 5,4-d '] bisoxazole, 2,6- (3,3'- Diaminodiphenyl) benzo [1,2-d: 4,5-d ′] bisoxazole.

Among these, amino (aminophenyl) benzoxazole isomers are preferable from the viewpoint of ease of synthesis. Here, “each isomer” refers to each isomer in which two amino groups of amino (aminophenyl) benzoxazole are determined according to the coordination position (eg, the above “formula 1” to “formula 4”). Each compound described in the above. These diamines may be used alone or in combination of two or more.
In the present invention, it is preferable to use 70 mol% or more of the aromatic diamine having the benzoxazole structure.

Examples of aromatic diamines having a diaminodiphenyl ether skeleton in the present invention include 4,4′-diaminodiphenyl ether (also referred to as ODA or DADE), 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, and derivatives thereof. Can be mentioned.
Examples of the aromatic diamine having a phenylenediamine skeleton in the present invention include p-phenylenediamine, m-phenylenediamine, o-phenylenediamine and derivatives thereof.

You may use the following aromatic diamine which is not limited to the above for the polyimide film in this invention.
For example, 4,4′-bis (3-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, 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-aminobenzylamine, p-aminobenzylamine, 3,3′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfoxide, 3,4′-diaminodiphenyl sulfoxide, 4, 4'-diaminodiphenyl sulfoxide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone 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) phenyl] 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-biphenoxy Nzophenone, 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) phenoxy] benzonitrile and the above fragrance Part or all of the hydrogen atoms on the aromatic ring in the aromatic diamine are halogen atoms, part or all of the hydrogen atoms of the alkyl group or alkoxyl group having 1 to 3 carbon atoms, the cyano group, or the alkyl group or alkoxyl group. And aromatic diamines substituted with a C 1-3 halogenated alkyl group or alkoxyl group substituted with.

As aromatic tetracarboxylic acids that can be preferably used in the polyimide film of the present invention, aromatic tetracarboxylic acids having a pyromellitic acid skeleton, that is, pyromellitic acid and anhydrides or halides thereof, aromatic tetracarboxylic acids having a biphenyltetracarboxylic acid skeleton Examples include acids, i.e. biphenyltetracarboxylic acid and anhydrides or halides thereof.
Without being limited thereto, the following aromatic tetracarboxylic acids may be used.

これらのテトラカルボン酸は単独で用いてもよいし、二種以上を併用してもよい。

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

  The solvent used when polyamic acid is obtained by polymerizing aromatic diamines and aromatic tetracarboxylic acid anhydrides is particularly limited as long as it dissolves both the raw material monomer and the polyamic acid to be produced. Although not preferred, polar organic solvents are preferred, such as N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide Hexamethylphosphoric amide, ethyl cellosolve acetate, diethylene glycol dimethyl ether, sulfolane, halogenated phenols and the like, among which N-methyl-2-pyrrolidone and N, N-dimethylacetamide are preferably applied. 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 20% by mass.

Conventionally known conditions may be applied for the polymerization reaction for obtaining the polyamic acid (hereinafter also simply referred to as “polymerization reaction”). As a specific example, in a temperature range of 0 to 80 ° C., 10 Stirring and / or mixing continuously for 30 minutes. 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, more preferably 4.0 dl / g or more, and still more preferably 5.0 dl / g or more. preferable.

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.
Vacuum degassing during the polymerization reaction is effective in producing a good quality polyamic acid solution.
Furthermore, in order to obtain the polyimide film of the present invention, it is possible to remove bubbles and dissolved gas in the solution in advance by treatment such as decompression when casting and applying a polyamic acid solution described below onto the support. This is an effective process.

  The support on which the polyamic acid solution is applied is only required to have smoothness and rigidity sufficient to form the polyamic acid solution into a film, and a drum or belt whose surface is made of metal, plastic, glass, porcelain, etc. And the like. A method using a polymer film having moderate rigidity and high smoothness is also a preferred embodiment. Among them, the surface of the support is preferably a metal, more preferably stainless steel that does not rust and has excellent corrosion resistance. The surface of the support may be plated with metal such as Cr, Ni, or Sn. The surface of the support can be mirror-finished or processed into a satin finish as required. The air volume and temperature in drying may be appropriately selected and adopted depending on the difference in the support, and the polyamic acid solution can be applied to the support by casting from a nozzle with a slit, extrusion by an extruder, squeegee coating, reverse coating, die Including, but not limited to, coating, applicator coating, wire bar coating and the like, conventionally known solution application means can be used as appropriate.

As imidization / heat treatment, a polyamic acid solution that does not contain a ring-closure (imidization) catalyst or a dehydrating agent is used, and the imidization reaction is advanced by subjecting to a heat treatment (so-called thermal ring closure method) or ring closure in the polyamic acid solution. Examples thereof include a chemical ring closure method in which a catalyst and a dehydrating agent are contained and an imidization reaction is performed by the action of the above ring closing catalyst and the dehydrating agent.
The heat treatment temperature of the thermal ring closure method is preferably 150 to 500 ° C. If the heat treatment temperature is lower than this range, it is difficult to sufficiently close the ring, and if it is higher than this range, the deterioration proceeds and the film tends to become brittle. A more preferable embodiment includes a two-stage heat treatment step having an initial stage heat treatment and a subsequent stage heat treatment in which a heat treatment is performed at 150 to 250 ° C. for 3 to 20 minutes and then heat treatment at 350 to 500 ° 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.

Whether it is a thermal ring closure reaction or a chemical ring closure method, the polyimide film precursor (also referred to as a green film) formed on the support may be peeled off from the support before it is completely imidized. The film may be peeled after imidization.
Although the thickness of a polyimide film is not specifically limited, Considering using it for the base substrate for printed wiring boards mentioned later, it is 5-150 micrometers, Preferably it is 10-100 micrometers. 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 preferably provided with a lubricant in the polyimide to give fine irregularities on the film surface to improve the slipping property of the film.
As the lubricant, inorganic or organic fine particles having an average particle diameter of about 0.03 μm to 3 μm can be used. Specific examples include titanium oxide, alumina, silica, calcium carbonate, calcium phosphate, calcium hydrogen phosphate, calcium pyrophosphate, Examples include magnesium oxide, calcium oxide, and clay minerals.

  In the present invention, the thermal expansion coefficient of the polyimide film is preferably in the range of 0 to 11 ppm / ° C, more preferably in the range of 2 to 10 ppm / ° C, and still more preferably in the range of 3 to 9 ppm / ° C. By using a polyimide film having such characteristics, the above-described metal-coated polyimide film having excellent durability can be obtained. If the coefficient of thermal linear expansion greatly exceeds this range, the dissociation from the coefficient of thermal linear expansion of the metal increases, and stress may be generated between the film and the metal surface when heated to cause a decrease in adhesive strength. In addition, since the region of about 12 to 18 is close to the thermal linear expansion coefficient of copper, which is a metal layer that is preferably used, it does not affect the film / metal adhesion. The dissociation from the thermal linear expansion coefficient of the element, particularly silicon or gallium athenite single crystal, is increased, and breakage of the junction is likely to occur during soldering or during a long-term temperature cycle. Furthermore, when the linear expansion coefficient is smaller than a predetermined range, the difference between both the metal and the semiconductor becomes large, so that the reliability is greatly lowered.

Water vapor permeability of the polyimide film in the present invention is preferably at least ^{3ml / m 2 · day · atm} , more preferably not less than ^{6ml / m 2 · day · atm} , more 12ml / m ² · day · atm is more preferred 20 ml / m ² · day · atm or more is particularly preferable. Polyimide is a material that easily absorbs moisture due to its imide structure. Moisture absorption of the base film is a troublesome problem that may cause various problems in the process of releasing absorbed moisture when heated. Such moisture that has been absorbed becomes particularly problematic at the bonding interface between the film and the metal. A high water vapor transmission rate means that moisture absorbed near the interface can be effectively released. Such an effect becomes more prominent as the water vapor transmission rate is higher, and is further promoted as the water vapor transmission rate is higher than the oxygen transmission rate.

Control of the oxygen permeability and water vapor permeability of such a polyimide film can be realized, for example, by compounding a polyimide film with a material that can control gas permeability. As such a gas permeability control material, polyvinylidene chloride, polyvinyl alcohol, ethylene-polyvinyl alcohol copolymer or the like is used for a polymer material, and alumina-silica ceramic thin film, zinc sulfide thin film, SiO is used for an inorganic material. _{A 2-x} thin film can be exemplified. Examples of the composite form include multilayering, blending, dispersion, solid solution, blending, alloying, and the like.

Hereinafter, the manufacturing method of the metal-coated polyimide film of the present invention, and the first metal layer and the second metal layer which are constituent elements thereof will be described.
First, the surface of the polyimide film is preferably subjected to surface treatment by plasma treatment. Such plasma is inert gas plasma, and nitrogen gas, Ne, Ar, Kr, and Xe are used as the inert gas. 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. There is no particular limitation on the plasma treatment method, and a plasma treatment apparatus used for forming a metal layer on the base film may be used. 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. Further, if the gas pressure is too high, the smoothness of the surface of the electrical insulating layer may be reduced. There is no particular limitation on the sputtering method, and DC bipolar sputtering, high-frequency sputtering, magnetron sputtering, counter target sputtering, ECR sputtering, bias sputtering, plasma controlled sputtering, multi-target sputtering, and the like can be used. Among these, direct current bipolar sputtering or high frequency sputtering is preferable. There are no particular restrictions on the output during sputtering processing, the gas pressure for generating plasma, and the processing temperature, so long as they can be handled by the sputtering apparatus. The output is usually 10 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. The film forming rate is 0.1 Å / second to 1000 Å / second, preferably 1 Å / second to 100 Å / second. If the film formation rate is too high, the formed metal film may be cracked. Moreover, when gas pressure is too high, there exists a possibility that adhesiveness may fall.

A first metal layer is then formed. The formation of the first metal layer in the present invention is a particularly preferable method for using a sputtering method excellent in thin film adhesion and thin film controllability. The sputtering method is not particularly limited, and methods such as DC magnetron sputtering, high-frequency magnetron sputtering, and ion beam sputtering are effectively used. Industrially, direct current sputtering is simple and sufficient film quality can be obtained. Those skilled in the art understand that a target is appropriately selected and used in accordance with the thin film to be formed.
As the first metal layer, Cr, Ta, Ti, Hf, Mo, W, Re, Ni—Cr, SiCr, TiCr, Cu—Mn—NiPd—Ag, Pd—Au—Fe, Cr—SiO, Cr— Examples thereof include MgF2, Au-SiO, tantalum nitride, partial tantalum nitride, titanium nitride, and partial titanium nitride. Ni-Cr and Ni-Co-Cr are preferable. More preferably, a NiCr target for sputtering of 99.9% or more is used. The thickness of the NiCr intermediate layer is required to be at least as small as the copper particles do not substantially enter the polyimide layer by heat treatment at 150 ° C. for 24 hours in the atmosphere (diffusion suppression effect). About 50 nm is preferable. If the film thickness is too thin, the copper particles penetrate into the polyimide layer under such conditions, and the diffusion suppressing layer is not effective. On the other hand, if it is too thick, it takes time to form the NiCr intermediate layer, which is not preferable in terms of production efficiency.

A second metal layer is then formed. The second metal layer in the present invention is a material for forming a circuit that is easily understood by those skilled in the art. In the present invention, there is no further particularly limited requirement. Examples include copper alloys whose main component is copper, Al, Au, Ag, Cu, Ni, and stainless steel. Preferably, copper having a purity of 99.99% or more is used. Although the copper thin film is formed with a film thickness of 100 nm or more, the present invention is a metal-coated polyimide film, and a circuit is formed after the plating process or through the etching process rather than being used as it is. Considering these subsequent processes, the film thickness is desirably 200 nm or more in order to facilitate circuit processing.
The film thickness of these first and second metal thin films is measured with a level difference measuring device by providing a mask on a part of the sample during sputtering or plating, and then removing the mask and making the difference from the unmasked part. Was determined by When the length of the step portion exceeded the measurement limit of the apparatus, the sputtering or plating time was adjusted so as to be within the measurement limit. Calculations were then based on thin film deposition at a constant rate.

  Next, a thick metal layer is formed as necessary. The thick metal layer is composed of a conductive layer and a thick layer, and the conductive layer may be formed by any one of a sputtering method, a vapor deposition method, and a wet electroless plating method, and preferably two or more. It is formed by combining methods. As the metal of the thick metal layer, silver, copper, gold, platinum, rhodium, nickel, aluminum, iron, zinc, tin, brass, white copper, bronze, monel, tin lead solder, tin copper solder, tin silver A system solder or the like is used, but copper is a preferred embodiment in terms of a balance between performance and economy. Electroplating can be used for forming the copper layer that is preferably used as the thickening layer of the thickening metal layer of the present invention. As the electroplating method, copper pyrophosphate plating or copper sulfate plating can be preferably used.

  The metal-coated polyimide film of the present invention thus obtained is coated with a photoresist on the copper layer side by an ordinary method, dried, and then exposed, developed, etched, and stripped of the photoresist by a step of removing the photoresist. Then, if necessary, solder resist coating, curing and electroless tin plating are performed to obtain a circuit board. Moreover, it is good also as a circuit formation base material by a semi-additive method, without forming a thickening layer. Further, it may be used as a laminated material when producing a multilayer substrate or a build-up substrate.

In the present invention, after the metal-coated polyimide film obtained in the above process is heat-treated at 150 ° C., the amount of residual metal other than Cu on the surface of the polyimide film treated with a sulfuric acid / hydrogen peroxide etching reagent is 1 μg / square cm. Less than 0 μg / square cm is essential.
The 150 ° C. heat treatment is performed in a dry oven (hot air oven) in 60 minutes. As the sulfuric acid / hydrogen peroxide etching reagent, one having a sulfuric acid concentration of 100 g / liter, a 35% hydrogen peroxide water concentration of 40 g / liter, and a copper concentration of 30 g / liter is used.
The treatment is immersed in an etching solution adjusted to a temperature of 25 ° C. and 5 ° C., and is gently swung, followed by 30 minutes, and then thoroughly washed with ion-exchanged water. The treatment time is a time sufficient to determine that the Cu content of the second metal layer is almost eluted and the amount of the remaining metal component does not change even if the treatment is continued further. If a thick metal layer is present, it is necessary to allow sufficient time to etch away the thick metal layer. It should be noted that the total amount of the treatment liquid needs to be sufficient so that the metal component is newly added to the treatment liquid by the test treatment and still falls within the composition ratio range.
The amount of the remaining metal may be normalized by the mass of the metal per unit area by performing general inorganic element analysis such as ICP method, atomic absorption method, or fluorescent X-ray method.
The residual metal amount of the present invention is essential to be 1 μg / square cm or less, preferably 0.6 μg / square cm or less, and more preferably 0.3 μg / square cm or less. When the residual metal amount exceeds this range, the durability of the conductor adhesive strength is lowered, and the insulation reliability is easily lowered due to migration. The lower limit of the remaining amount does not need to be particularly limited, and it is still more preferable to reduce it to the measurement limit of an analytical instrument used for quantitative analysis.
In the present invention, the remaining amount is realized as a result. The means for forming the residual amount is not particularly limited. For example, it is important that the first metal layer is made of a homogeneous alloy having no segregation and is operated so as not to cause a composition gradient in the metal layer. is there. It is preferable to cool the substrate film so that the temperature of the surface layer of the polyimide film as the substrate is substantially 250 ° C. or lower, preferably 150 ° C. or lower, more preferably 50 ° C. or lower.

Hereinafter, the effectiveness of the present invention will be described with reference to examples, but the present invention is not limited thereto. In addition, the evaluation method of the physical property in the following examples is as follows.
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).

3. Tensile modulus, tensile breaking strength and tensile breaking elongation of polyimide film The film after drying was cut into strips having a length of 100 mm and a width of 10 mm in the longitudinal direction (MD direction) and the width direction (TD direction), respectively, and used as test pieces. , Using a tensile tester (manufactured by Shimadzu Corporation, trade name: Autograph, model name: AG-5000A), measuring at a tensile speed of 50 mm / min and a distance between chucks of 40 mm to obtain tensile elastic modulus, tensile strength and tensile breaking elongation. It was.

5. Linear expansion coefficient (CTE) of polyimide film
The expansion / contraction rate was measured under the following conditions, and the range from 30 to 300 ° C. was divided at 15 ° C. intervals and obtained from the average value of the expansion / contraction rate / temperature of each divided range.
Device name: TMA4000S manufactured by MAC Science
Sample length; 20mm
Sample width: 2 mm
Temperature rise start temperature: 25 ° C
Temperature rising end temperature: 400 ° C
Temperature increase rate: 5 ° C / min
Atmosphere: Argon

6). Melting point of polyimide film, glass transition temperature A sample was subjected to DSC measurement under the following conditions, and a melting point (melting peak temperature Tpm) and a glass transition point (Tmg) were determined under the following measurement conditions in accordance with JIS K7121.
Device name: DSC3100S manufactured by MAC Science
Pan ： Aluminum pan (non-airtight)
Sample mass: 4mg
Temperature rising start temperature: 30 ° C
Temperature increase rate: 20 ° C / min
Atmosphere: Argon

7). Thermal Decomposition Temperature of Polyimide Film The thermal decomposition temperature was defined as a 5% mass loss after TGA measurement (thermobalance measurement) of a sufficiently dried sample under the following conditions.
Device name: TG-DTA2000S manufactured by MAC Science
Pan ： Aluminum pan (non-airtight)
Sample mass: 10 mg
Temperature rising start temperature: 30 ° C
Temperature increase rate: 20 ° C / min
Atmosphere: Argon

8). Initial conductor adhesion of metal-coated polyimide film A 90-degree peel test was performed by a method in accordance with JIS C5016.
In addition, since the conductor cut frequently occurred in the copper foil of 5 μm and satisfactory evaluation could not be performed, the adhesive strength was evaluated by further increasing the thickness of the copper foil to 18 μm by electroplating.
9. Conductor adhesion after moisture and heat resistance test of metallized polyimide film After treatment for 100 hours under a PCT tester manufactured by Hirayama Seisakusho at 121 ° C and 2 atm (saturated), a 90 ° peel test is performed in accordance with JIS5016. I went there.

10. Migration resistance of metal-coated polyimide film A voltage (DC60V) is applied to a comb electrode with a pitch of 40μm, and it is placed in a constant temperature and humidity chamber (FX412P type, manufactured by ETAC) at 85 ° C and 85% RH. The insulation resistance value was measured and recorded every 5 minutes as it was, and the time for the resistance value between the lines to reach 100 M ohms or less was measured for migration evaluation.

[Polymeric acid solution polymerization example 1]
(Preliminary dispersion of inorganic particles)
1.22 parts by mass of amorphous silica spherical particles Seahoster KE-P10 (manufactured by Nippon Shokubai Co., Ltd.), 420 parts by mass of N-methyl-2-pyrrolidone, the wetted part of the container, and the infusion pipe are austenitic stainless steel The mixture was placed in a container of SUS316L and stirred with a homogenizer T-25 basic (manufactured by IKA Labortechnik) at a rotation speed of 1000 rpm for 1 minute to obtain a preliminary dispersion. The average particle size in the preliminary dispersion was 0.11 μm.
(Preparation of polyamic acid solution)
A nitrogen inlet tube, a thermometer, a liquid contact part of a container equipped with a stirring rod, and a pipe for infusion were substituted with nitrogen in the reaction container made of austenitic stainless steel SUS316L, and then 223 parts by mass of 5-amino-2- ( p-Aminophenyl) benzoxazole was added. Next, 4000 parts by mass of N-methyl-2-pyrrolidone was added and completely dissolved, and then the preliminary dispersion obtained above was added with 420 parts by mass and 217 parts by mass of pyromellitic dianhydride. When the mixture was stirred at ° C. for 24 hours, a brown viscous polyamic acid solution A was obtained. The reduced viscosity (ηsp / C) was 3.8 dl / g.

[Polymeric acid solution polymerization example 2]
Nitrogen introduction tube, thermometer, vessel wetted part equipped with stirring rod, and infusion pipe were replaced with nitrogen in the reaction vessel of austenitic stainless steel SUS316L, and then 5-amino-2- (p-aminophenyl) ) After adding 223 parts by mass of benzoxazole and 4416 parts by mass of N, N-dimethylacetamide and completely dissolving them, Snowtex DMAC-ST30 (manufactured by Nissan Chemical Industries, Ltd.) 40 in which colloidal silica is dispersed in dimethylacetamide .5 parts by mass (including 8.1 parts by mass of silica) and 217 parts by mass of pyromellitic dianhydride are added and stirred at a reaction temperature of 25 ° C. for 24 hours to obtain a brown and viscous polyamide acid solution B. It was. Ηsp / C of this product was 4.0 dl / g.

[Polymeric acid solution polymerization example 3]
(Preliminary dispersion of inorganic particles)
7.6 parts by weight of amorphous silica spherical particle Seahoster KE-P10 (manufactured by Nippon Shokubai Co., Ltd.), 390 parts by weight of N-methyl-2-pyrrolidone, the liquid contact part of the container, and the infusion pipe are austenitic stainless steel SUS316L And stirred for 1 minute at a rotation speed of 1000 rpm with a homogenizer T-25 basic (manufactured by IKA Labortechnik) to obtain a preliminary dispersion.
(Preparation of polyamic acid solution)
The liquid contact part of the vessel equipped with a nitrogen introduction tube, a thermometer, a stirring rod, and the pipe for infusion were substituted with nitrogen in the reaction vessel made of austenitic stainless steel SUS316L, and then 200 parts by mass of diaminodiphenyl ether was added. Next, after 3800 parts by mass of N-methyl-2-pyrrolidone was added and completely dissolved, 390 parts by mass and 217 parts by mass of pyromellitic dianhydride were added to the preliminary dispersion obtained above. When the mixture was stirred at 0 ° C. for 5 hours, a brown viscous polyamic acid solution C was obtained. The reduced viscosity (ηsp / C) was 3.7 dl / g.

[Polymeric acid solution polymerization example 4]
(Preliminary dispersion of inorganic particles)
3.7 parts by mass of amorphous silica spherical particles Seahoster KE-P10 (manufactured by Nippon Shokubai Co., Ltd.), 420 parts by mass of N-methyl-2-pyrrolidone, and the infusion part are austenitic stainless steel SUS316L And stirred for 1 minute at a rotation speed of 1000 rpm with a homogenizer T-25 basic (manufactured by IKA Labortechnik) to obtain a preliminary dispersion.
(Preparation of polyamic acid solution)
The wetted part of the vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod, and the infusion piping were substituted with nitrogen in the reaction vessel made of austenitic stainless steel SUS316L, and then 108 parts by mass of phenylenediamine was added. Next, after 3600 parts by mass of N-methyl-2-pyrrolidone was added and completely dissolved, 420 parts by mass and 292.5 parts by mass of diphenyltetracarboxylic dianhydride were added to the preliminary dispersion obtained above. When the mixture was stirred at 25 ° C. for 12 hours, a brown viscous polyamic acid solution D was obtained. The reduced viscosity (ηsp / C) was 4.5 dl / g.
[Production Examples 1 to 4]
The polyamic acid solution obtained in Polymerization Examples 1 to 4 was coated on the non-lubricant surface of polyethylene terephthalate film A-4100 (manufactured by Toyobo Co., Ltd.) using a comma coater (gap: 150 μm, coating width). 1240 mm), and dried for 18 minutes at 105 ° C. using a continuous blower dryer. The polyamic acid film which became self-supporting after drying was peeled off from the support and cut at both ends to obtain respective green films having a thickness of 21 μm and a width of 1200 mm.

These green films thus obtained were passed through a pin tenter having a heat treatment path having five heating zones, the pin sheet spacing was 1140 mm, that is, 30 mm at both ends of the green film were inserted into the pins, and the first stage was 5 at 150 ° C. Minute, second stage 210 ° C., third stage 480 ° C., fourth stage 480 ° C., gradually cooled to 150 ° C. in the fifth stage, and further cooled to room temperature, where the flatness of both ends of the film is poor It cut off with the slitter, wound up in roll shape, and obtained each polyimide film of the manufacture examples 1-4 which exhibits brown.
Table 1 shows the physical properties of the obtained polyimide film.

[Example 1]
The polyimide film shown in Production Example 1 was slit into a width of 250 mm, and then set in a roll-to-roll type plasma surface treatment apparatus. First, the surface of the polyimide film was treated with oxygen glow discharge. Conditions during processing O ₂ gas pressure 2 × 10 ^-3 Torr, flow rate 50 SCCM, discharge frequency 13.56 MHz, output 250 W, treatment time, since the effective plasma irradiation width film feeding speed 0.1 m / min is about 10cm One plasma irradiation time is 1 minute. Thereafter, the NiCr base thin film layer having a thickness of 15 nm was formed on one surface of the film by a DC magnetron sputtering method using an argon gas with a NiCr alloy as a target. The degree of vacuum at the time of forming the thin film layer is 3 × 10 ⁻³ Torr. During sputtering of the film, the temperature on the sputtering surface side was 370 ° C. Then, a copper thin film layer having a thickness of 250 nm was immediately formed by DC magnetron sputtering using argon gas with copper as a target. The composition of the target NiCr alloy was Ni 80% by mass, Cr 20% by mass and purity 3N, and a homogeneous material without segregation or composition gradient was used. The target Cu had a purity of 4N.

Each target has a rectangular shape with a width of 12 cm in the film feeding direction and a width of 27 cm in the film feeding direction. Four rectangular targets are installed in the film feeding direction. Two targets were approaching each other, but they were used for NiCr. Since the distance between the target and the target used for Cu is separated, the NiCr sputtered atoms and Cu atoms do not reach the film after being mixed in a vacuum, and the underlying NiCr thin film Each Cu thin film is formed without being mixed with each other to form a two-layer thin film.
The sputtering device is a roll-to-roll system, and surface treatment, NiCr layer preparation, and Cu layer preparation are sequentially performed while the film is moved from the roll to the unwinding chamber, the sputtering chamber, the preliminary chamber, and the winding chamber. And then wound on a roll.
Each chamber is roughly partitioned by a slit. In the sputtering chamber, the film is in contact with the chill roll, and is cooled by the temperature of the chill roll (−5 ° C.), but does not use one NiCr target, one target near the unwinding side, and then from the two Cu targets. A thin film is formed by the metal particles.
Next, copper electroplating was performed on the copper thin film. The obtained metal-coated film is re-fixed to a plastic frame, and a thick copper-plated layer (thickened layer) having a thickness of 5 μm is formed using a copper sulfate plating bath. Obtained.

A 150 cm × 5 cm sample was cut out from the obtained metal-coated polyimide film, heat-treated in a dry oven at 150 ° C. for 60 minutes, and then adjusted to 25 ° C., sulfuric acid concentration 100 g / liter, 35% hydrogen peroxide solution It was immersed in an etching reagent having a concentration of 40 g / liter and a copper concentration of 30 g / liter in 3000 ml for 30 minutes with gentle rocking, then thoroughly washed with deionized water and dried. The amount of metal on the surface of the film after treatment was quantified by atomic absorption, and the amount of metal per unit area was calculated. The results are shown in Table 2.
Using the obtained metal-coated polyimide film, photoresist: FR-200, manufactured by Shipley Co., Ltd. was applied and dried, then contacted and exposed with a glass photomask, and further developed with a 1.2% by mass KOH aqueous solution. Next, etching is performed with a cupric chloride etching line containing HCl and hydrogen peroxide at 40 ° C. and a spray pressure of ² kgf / cm ² to form a test pattern necessary for an evaluation test described later, and then a thickness of 0.5 μm. Electroless tin plating was performed. Thereafter, annealing was performed at 125 ° C. for 1 hour.
Test evaluation was performed using the obtained test pattern. The results are shown in Table 2.

[Example 2]
A metal-coated polyimide film was obtained in the same manner as in Example 1 except that the polyimide film obtained in Production Example 2 was used. The results of evaluation in the same manner are shown in Table 2.
Example 3
A metal-coated polyimide film was obtained in the same manner as in Example 1 except that the polyimide film obtained in Production Example 3 was used. The results of evaluation in the same manner are shown in Table 2.
Example 4
A metal-coated polyimide film was obtained in the same manner as in Example 1 except that the polyimide film obtained in Production Example 4 was used. The results of evaluation in the same manner are shown in Table 2.

[Comparative Example 1]
The polyimide film obtained in Production Example 1 was first slit into a width of 250 mm. Subsequently, it was set in a roll-to-roll type plasma surface treatment apparatus, and the surface of the polyimide film was treated with oxygen glow discharge. The processing conditions are O ₂ gas pressure 2 × 10 ⁻³ Torr, flow rate 50 SCCM, discharge frequency 13.56 MHz, output 250 W, processing time 1 because the film feed rate is 0.1 m / min and the effective plasma irradiation width is about 10 cm. The plasma irradiation time at the location is 1 minute. Thereafter, the Ni—Cr layer having a thickness of 30 nm is formed on one side of the film by a DC magnetron sputtering method using argon gas using a target in which a Cr chip is placed on a part of the Ni target. It was. The degree of vacuum at the time of forming the thin film layer is 3 × 10 ⁻³ Torr. Thereafter, as a second metal layer, a copper thin film layer having a thickness of 250 nm was formed by DC magnetron sputtering using argon gas immediately with copper as a target. The target Cu had a purity of 4N. Thereafter, the same operation as in the examples was carried out to obtain a metal-coated polyimide film, which was similarly evaluated. The evaluation results are shown in Table 2.

  As described above, the metal-coated polyimide film of the present invention has excellent wet heat durability, and electronic components, circuit components, printed wiring boards, module substrates, interposers, mechanical components, and display elements that are required to have high reliability. It can be usefully used as a material constituting an input / output element.

Claims (2)

  In a metal-coated polyimide film in which (1) a first metal layer containing no Cu and (2) a second metal layer mainly composed of Cu are sequentially laminated on at least one surface of the polyimide film, the metal-coated polyimide film is Metal-coated polyimide, characterized in that the amount of residual metal other than Cu on the surface of the polyimide film treated with a sulfuric acid / hydrogen peroxide etching reagent after heat treatment at 150 ° C. is less than 1 μg / square cm and 0 μg / square cm or more the film.   The metal-coated polyimide film according to claim 1, wherein the polyimide film is a polyimide film obtained by condensation polymerization of a diamine having a benzoxazole skeleton and an aromatic tetracarboxylic dianhydride.