JP2002316386A - Copper-clad laminate and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper-clad laminate having a thin copper foil layer which is excellent in adhesion, moisture absorption properties, and heat resistance. SOLUTION: The copper-clad laminate has copper foil 1-8 μm in thickness, an adhesive layer containing a thermoplastic polyimide resin as a main component, and a heat resistant film. The method for producing the copper-clad laminate includes a process for forming the adhesive layer on the heat resistant film, a process for arranging the copper foil with a carrier on the surface of the adhesive layer, a process in which the obtained laminate is hot-pressed to bond the adhesive layer in the laminate and the copper foil with the carrier together, and a process for peeling off the carrier.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper-clad laminate in which a copper foil having a thickness of 8 .mu.m or less is laminated on one or both sides of a resin layer, and a method for producing the same. The present invention relates to a copper-clad laminate excellent in various properties such as heat resistance, adhesion between a copper foil and a resin layer, and fine line pattern formability, and a method for producing the same.

[0002]

2. Description of the Related Art With the rapid progress of IT technology in recent years,
2. Description of the Related Art Higher performance, higher functionality, and smaller size of electronic devices such as portable terminal devices, computers and displays are rapidly progressing. Along with this, electronic components such as semiconductor elements used in electronic devices and substrates on which they are mounted have been required to have higher density and higher performance.

[0003] Flexible printed wiring boards (hereinafter FPCs)
For this reason, thinning of wiring patterns and multi-layer formation will be performed, and a component mounting FPC in which components are directly mounted on the FPC, and a double-sided FP in which a circuit is formed on both sides.
C, multilayer FPCs in which a plurality of FPCs are stacked and the layers are connected by wiring have appeared. For this reason, thinner materials and dimensional stability have been required more strictly for materials constituting FPCs.

In general, an FPC is manufactured by bonding a copper foil to one or both sides of a heat-resistant film via an adhesive layer to form a copper-clad laminate, and etching the copper foil to form a desired circuit pattern. Is done. As the heat-resistant film, a film made of an aromatic polyamide resin or a polyimide resin having excellent heat resistance, mechanical properties and other various properties is widely used. For the adhesive layer, epoxy resin or acrylic resin with excellent insulation and heat resistance were used,
Resins containing a thermoplastic polyimide resin as a main component, which is excellent in balance between properties of low moisture absorption and heat resistance, have come to be used. On the other hand, excellent heat resistance of the heat-resistant film,
In order not to impair the insulation, recently, a method of manufacturing a copper-clad laminate without forming an adhesive layer, that is, a polyimide resin or a polyamic acid solution that is a precursor thereof is directly applied to a copper foil, and dried and imidized. A method of manufacturing a copper-clad laminate by making the copper clad laminate has been adopted.

Conventionally, a copper foil having a thickness of 9 to 30 μm has been used for the FPC.
It has become necessary to use thinner copper foil. However, since the copper foil alone has poor self-supporting property, it is difficult to use a copper foil of 9 μm or less for the manufacture of FPC. Recently, a copper foil for a carrier has a thickness of 8 μm or less via a release layer. It has been proposed to use an ultra-thin copper foil with a carrier on which a copper foil is formed [Journal of Japan Institute of Electronics Packaging Vol4, No2, 108-112 (2)
001)].

However, when a polyimide resin solution or a polyamic acid solution is directly applied to an ultra-thin copper foil with a carrier to produce a copper-clad laminate, it must be heated at a high temperature for a long time, and the delamination layer may be melted. Alternatively, there is a problem in that the copper foil for a carrier and the ultra-thin copper foil cannot be peeled off due to decomposition. Therefore, it was difficult to obtain a copper-clad laminate having a copper foil layer of 8 μm or less.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art.
In order to cope with higher performance, a technology for increasing the density and performance of electronic components such as semiconductor elements used in electronic devices and a substrate on which they are mounted is provided. The present invention provides a technique for thinning a copper foil layer required for finer wiring pitch of a flexible printed wiring board (FPC) and the like, and excellent adhesiveness, moisture absorbing properties, heat resistance and the like obtained by the technique. A laminate is provided.

[0008]

According to the present invention, a thickness of 1 to 8 is provided.
The present invention relates to a copper-clad laminate including a μm copper foil, an adhesive layer mainly containing a thermoplastic polyimide resin, and a heat-resistant film.

Preferably, the heat-resistant film is a polyimide film.

Preferably, the adhesive layer is formed at 150 ° C. to 2 ° C.
It has a glass transition temperature of 50 ° C.

The present invention also relates to a method for producing a copper-clad laminate comprising a copper foil having a thickness of 1 to 8 μm, the method comprising:
A step of forming an adhesive layer on the heat-resistant film; a step of arranging a copper foil with a carrier on the surface of the adhesive layer; heating and pressing the obtained laminate to form an adhesive layer and a copper foil with a carrier in the laminate. And peeling off the carrier.

Preferably, the bonding step is performed at a temperature higher by 50 ° C. to 100 ° C. than the glass transition temperature of the bonding layer.

The copper-clad laminate of the present invention has a thickness of 1 to 8 μm.
Copper foil, an adhesive layer containing thermoplastic polyimide resin as a main component, and a heat-resistant film, the copper-clad laminate,
A step of forming an adhesive layer on the heat-resistant film; a step of arranging a copper foil with a carrier on the surface of the adhesive layer; heating and pressing the obtained laminate to form an adhesive layer and a copper foil with a carrier in the laminate. And peeling off the carrier.

Preferably, the bonding step is performed at a temperature 50 ° C. to 100 ° C. higher than the glass transition temperature of the bonding layer.

[0015] Preferably, the heat resistant film is a polyimide film.

Preferably, the adhesive layer has a temperature of 150 ° C. to 25 ° C.
It has a glass transition temperature of 0 ° C.

[0017]

Embodiments of the present invention will be described below. First, the configuration of the copper clad laminate according to the present invention will be described.

The copper-clad laminate of the present invention has a structure in which a copper foil having a thickness of 8 μm or less is laminated on one or both surfaces of a heat-resistant film via an adhesive layer containing a thermoplastic polyimide resin as a main component. . The lower limit of the thickness of the copper foil is preferably 1 μm. If it is less than 1 μm, the reliability of conduction of the FPC is impaired due to disconnection of the obtained circuit. As the heat-resistant film, for example, aromatic polyester film, aromatic polyamide film or polyimide film is used, heat resistance, tensile elastic modulus, mechanical properties such as breaking strength, flexibility and low water absorption and the like A polyimide film is most preferably used because it is excellent in mutual balance of various properties.

The resin used for the adhesive layer in the copper-clad laminate of the present invention is a resin containing a thermoplastic polyimide resin as a main component because of its excellent insulating properties and heat resistance (particularly, long-term heat resistance of 200 ° C. or more). Preferably, it is used. Also, the adhesive layer preferably has a glass transition temperature in the range of 150C to 250C.

Hereinafter, the case where the heat-resistant film is a polyimide film will be described more specifically by way of example.

The polyimide film can be manufactured by a known method. That is, this film can be obtained by casting or applying a solution containing a polyamic acid, which is a precursor material of polyimide, to a support, and then chemically or thermally imidizing the solution.

The polyamic acid, which is a precursor substance of the polyimide according to the present invention, usually has at least one acid dianhydride and at least one diamine as starting materials, and contains both in a substantially equimolar amount in an organic solvent. It can be produced by stirring until the polymerization is completed while controlling the reaction conditions such as temperature after dissolving the amount and the amount.

As the above acid dianhydride, specifically,
Pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 1,2,5,6-naphthalene Tetracarboxylic dianhydride, 2,2 ', 3
3′-biphenyltetracarboxylic dianhydride, 3,
3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-oxydiphthalic dianhydride, p-phenylenebis (trimellitic acid monoester anhydride), 1,1 '-Biphenylbis (trimellitic acid monoester anhydride) and their analogs (derivatives) are used.

Among the acid dianhydrides exemplified above, pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic acid Dianhydride, p-phenylene bis (trimellitic acid monoester acid anhydride) and 4,4′-biphenylbis (trimellitic acid monoester acid anhydride) are particularly preferred. These acid dianhydrides may be used alone,
Also, two or more kinds may be used in combination at an arbitrary ratio.

Examples of the above-mentioned diamine include, for example, 3,3′-dimethylbenzidine, 3,3′-dimethoxybenzidine, 3,3′-dichlorobenzidine,
4,4'-diaminodiphenyl sulfide, 4,4'-
Diaminodiphenyl sulfone, 4,4′-diaminodiphenyl ether, 1,5-diaminonaphthalene, 1,4
-Diaminobenzene (p-phenylenediamine), 1,
3-diaminobenzene, 1,2-diaminobenzene,
4,4'-diaminobenzanilide, 3,4'-diaminobenzanilide and their analogs (derivatives)
Are used.

Among the diamines exemplified above, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine,
3,3′-dichlorobenzidine, 4,4′-diaminobenzanilide, 4,4′-diaminodiphenyl ether, and p-phenylenediamine are more preferred, and 4,4 ′
Diaminobenzanilide is particularly preferred. These diamines may be used alone or in combination of two or more at an arbitrary ratio.

A combination of an acid dianhydride and a diamine,
The molar ratio (compounding ratio) of each compound when two or more types of acid dianhydrides are used, and the compounding ratio of each compound when two or more types of diamines are used, are such that the polyimide film has a desired elastic modulus, linear expansion coefficient, and moisture expansion. What is necessary is just to select and set suitably so that it may have characteristics, such as a coefficient. Among them, pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ′ are preferred in terms of excellent heat resistance, dimensional stability, and adhesiveness of the copper-clad laminate. 4,4,4'-biphenyltetracarboxylic dianhydride, p-phenylenebis (trimellitic acid monoester anhydride), 4,4'-diaminobenzanilide, 4,4'-diaminodiphenyl ether, p-phenylene A combination containing at least one of diamines is more preferable, and p-phenylenebis (trimellitic acid monoester anhydride) is more excellent in the mutual balance of various properties such as low water absorption and flexibility. Combinations containing 4,4'-diaminobenzanilide are particularly preferred.

When two or more acid dianhydrides are used, the proportion of p-phenylenebis (trimellitic acid monoester anhydride) in the total amount of the acid dianhydrides should be 40 mol% or more. Is more preferable, when two or more kinds of diamines are used, the proportion of 4,4′-diaminobenzanilide in the total amount of the diamines is
More preferably, it is at least 50 mol%.

By appropriately combining the acid dianhydride and the diamine, a polyimide film having desired properties such as elastic modulus, linear expansion coefficient and hygroscopic expansion coefficient can be easily obtained.

Examples of the organic solvent used for obtaining the polyamic acid include, for example, N, N-dimethylformamide (DMF), N, N-dimethylacetamide (D
An amide solvent such as MAc) and N-methyl-2-pyrrolidone (NMP) is used. Among the organic solvents exemplified above, N, N-dimethylformamide is particularly preferred. These organic solvents may be used alone, or may be a mixed solvent obtained by mixing two or more kinds at an arbitrary ratio. The polyamic acid solution is obtained by dissolving the acid dianhydride and the diamine in the organic solvent and then polymerizing.

More specifically, for example, a method in which a diamine is dissolved in an organic solvent and a substantially equimolar amount of an acid dianhydride is mixed with the diamine and polymerized. As a method of mixing the acid dianhydride, the acid dianhydride in a powder form or the like may be directly mixed, or a solution in which the acid dianhydride is dissolved in an organic solvent may be mixed. More preferably, a method in which an acid dianhydride and a solution in which an acid dianhydride is dissolved in an organic solvent is mixed with a solution obtained by dissolving a diamine in water.

That is, a solution prepared by dissolving a diamine in an organic solvent is added in an amount of 70 mol% to 98.5 mol% based on the diamine.
It is more preferable that the acid dianhydride is mixed as it is, and then mixed as a solution in which the remaining acid dianhydride is dissolved in an organic solvent. In addition to the above-mentioned method in which all diamines are dissolved in an organic solvent before mixing the acid dianhydride, the acid dianhydride is mixed in a solution in which a part (or one component) of the diamine is dissolved in the organic solvent. Thereafter, a method of mixing the remaining diamine (or other components) or a method of sequentially mixing the diamine and the acid dianhydride in the organic solvent can be adopted. Furthermore, a method in which the mixing order of the acid dianhydride and the diamine is changed, that is, a solution in which the acid dianhydride is dissolved in an organic solvent is mixed with the acid dianhydride and a substantially equimolar amount of the diamine. A method of polymerizing can also be adopted. Therefore, the mixing order and mixing method of the acid dianhydride and the diamine are as follows:
There is no particular limitation.

The temperature at which the acid dianhydride and the diamine are polymerized is preferably in the range of 0 ° C. to 80 ° C. In addition, since the polymerization is inhibited by the presence of water, the polymerization reaction is preferably performed in a dehumidified atmosphere.

The concentration of the polyamic acid in the polyamic acid solution is preferably in the range of 10% by weight to 25% by weight as a solid content. By using the acid dianhydride and the diamine so that the concentration of the polyamic acid is within the above range, a polyamic acid having a suitable molecular weight can be obtained, and a solution having a suitable viscosity can be obtained.

The imidation may be performed by any one of a thermal curing method and a chemical curing method. The heat curing method is a method in which the imidization reaction proceeds only by heating without using a dehydrating ring-closing agent or the like. The chemical curing method is a method in which a chemical conversion agent and a catalyst are added to a polyamic acid solution to advance an imidization reaction. Of these methods, the chemical cure method is more preferred. Further, a chemical curing method and a heat curing method may be used in combination.

Examples of the above chemical converting agents include aliphatic acid anhydrides, aromatic acid anhydrides, N, N'-dialkylcarbodiimides, lower aliphatic halides, halogenated lower fatty acid anhydrides, and arylphosphonic acids. Dihalides, thionyl halides and the like are used. One of these chemical conversion agents may be used alone, or two or more thereof may be used in combination. Among the chemical conversion agents exemplified above, aliphatic acid anhydrides such as acetic anhydride, propionic anhydride, and lacnic anhydride, and mixtures of these compounds are more preferred.

As the above catalyst, aliphatic tertiary amines, aromatic tertiary amines, heterocyclic tertiary amines and the like are used. These catalysts may be used alone or in combination of two or more. Among the catalysts exemplified above, heterocyclic tertiary amines such as isoquinoline, β-picoline and pyridine are particularly preferred.

The conditions for imidization are as follows:
The thickness may be set as appropriate depending on the thickness of the film to be formed, whether the thermal curing method and / or the chemical curing method is employed, and the like. Hereinafter, a method for producing a polyimide film from a polyamic acid solution using a chemical curing method as a method for producing a heat-resistant film will be described more specifically.

First, a polyamic acid solution is obtained by the above-described method. After the chemical conversion agent and the catalyst are added to the polyamic acid solution, they are cast or coated on a suitable support. Next, this is heated gently at a temperature of, for example, about 100 ° C. to activate the chemical conversion agent and the catalyst, and to partially cure (imidize) or partially dry the polyamic acid film ( (Hereinafter referred to as a gel film).

The gel film has a self-supporting property in the intermediate stage of imidization from polyamic acid to polyimide. The gel film is in a partially cured (imidized) or partially dried state, and contains a polyamic acid and a polyimide obtained by imidating the polyamic acid. Next, in order to suppress shrinkage in the tenter process, the end of the obtained gel film is held using a tenter clip or pin for suppressing shrinkage. Thereafter, the gel film is dried and imidized by heating the gel stepwise to obtain a polyimide film.

More specifically, a method in which a gel film is divided into a plurality of sections by a partition plate and passed through a tenter furnace in which the temperature is set for each section for 15 seconds to 400 seconds, and heated. is there. The temperature in the furnace is preferably set so that the gel film is heated stepwise from a temperature of about 200 ° C. to finally a temperature of about 400 ° C. Further, in order to obtain a polyimide film having more uniform thickness and quality of various characteristics, it is preferable to heat the gel film in the width direction without temperature unevenness. Thereby, a polyimide film as a heat-resistant film in the adhesive film is obtained.

The molecular weight of the polyimide is not particularly limited, but the number average molecular weight of the polyamic acid, which is a precursor of the polyimide, is 100,000 or more so that the strength of the adhesive film can be maintained. Is more preferable. Incidentally, it is difficult to directly measure the molecular weight because polyimide is insoluble, but the molecular weight of polyamic acid can be measured by GPC (gel permeation chromatography).

Next, a method for preparing a thermoplastic polyimide constituting the adhesive layer will be described. The thermoplastic polyimide can be obtained basically by the same manufacturing method as the method for manufacturing the polyimide film. Acid dianhydrides suitable for obtaining polyamic acid, which is a precursor of thermoplastic polyimide, specifically include, for example, 3,3 ′,
4,4′-biphenyltetracarboxylic dianhydride, 2,
2 ', 3,3'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride Anhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) propane dianhydride, 1,1-bis (2,
3-dicarboxyphenyl) ethane dianhydride, 1,1-
Bis (3,4-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) ethane dianhydride, 3,3 ′, 4,4'-diphenylethertetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, ethylenebis (trimellitic acid monoester anhydride), bisphenol A bis (trimellitic acid monoester) Acid anhydrides) and their analogs (derivatives). Among the acid dianhydrides exemplified above, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, ethylene bis (tri Particularly preferred are melitic acid monoester acid anhydride) and bisphenol A bis (trimellitic acid monoester acid anhydride). One of these acid anhydrides may be used alone, or two or more thereof may be used in combination at an arbitrary ratio.

As the diamine suitable for obtaining the polyamic acid which is a precursor substance of the thermoplastic polyimide, specifically, for example, the diamine is 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylmethane ,
3,3′-dimethylbenzidine, 3,3′-dimethoxybenzidine, 3,3′-dichlorobenzidine, 3,3 ′
-Dihydroxybenzidine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 4,4 '
-Diaminodiphenyl ether, 1,5-diaminonaphthalene, 4,4'-diaminodiphenyldiethylsilane, 4,4'-diaminodiphenylsilane, 4,4'-
Diaminodiphenylethylphosphine oxide, 1,3
-Diaminobenzene, 1,2-diaminobenzene, 2,
2-bis (4-aminophenoxyphenyl) propane,
1,2- (4-aminophenoxyethoxy) ethane and their analogs (derivatives) are used.

Among the diamines exemplified above, 3,3'-dihydroxybenzidine, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone,
4,4′-diaminodiphenyl ether, 2,2-bis (4-aminophenoxyphenyl) propane, 1,2-
(4-Aminophenoxyethoxy) ethane is particularly preferred.

One of these diamines may be used alone, or two or more of them may be used in combination at an arbitrary ratio.
A combination of an acid dianhydride and a diamine, or a molar ratio (blending ratio) of each compound when two or more acid dianhydrides are used,
When two or more kinds of diamines are used, the compounding ratio of each compound may be appropriately selected and set so as to obtain a thermoplastic polyimide. Polyamic acid, which is a precursor of the thermoplastic polyimide, has at least one type of acid dianhydride and at least one type of diamine as starting materials,
After dissolving both in a substantially equimolar amount in an organic solvent,
It can be obtained by stirring until polymerization is completed while controlling reaction conditions such as temperature.

The glass transition temperature of the obtained thermoplastic polyimide resin is preferably in the range of 150 ° C. to 250 ° C., and particularly preferably in the range of 170 ° C. to 240 ° C. When the glass transition temperature is lower than 150 ° C., the heat resistance of the substrate material such as a metal foil laminate or FPC (particularly 200
(250 ° C. long-term heat resistance), and if the temperature exceeds 250 ° C., the bonding temperature at the time of bonding with the metal foil must be increased in order to exhibit excellent bonding strength. There is a problem that the copper foil cannot be removed.

In the present invention, a monomer other than the acid dianhydride and the diamine may be used, if necessary, as long as various properties to be provided as the thermoplastic polyimide resin are not impaired.
For example, an epoxy monomer may be used as a component of the starting material. Thermoplastic polyimide can be obtained by chemically or thermally imidizing the polyamic acid. In addition, epoxy resin, filler, silane-based coupling agent, titanate-based coupling agent, etc. are mixed with thermoplastic polyimide resin within the range where the glass transition temperature of the adhesive does not exceed a suitable range, and used as a resin for the adhesive layer. can do.

The copper-clad laminate according to the present invention can be obtained by laminating a copper foil on one side or both sides of a heat-resistant film via an adhesive layer. As a method of laminating the adhesive layer, specifically, for example, a method in which a film mainly composed of thermoplastic polyimide is thermally fused to a heat-resistant film; a gel film of thermoplastic polyimide is thermally fused to a heat-resistant film. After that, a method of further imidization; a method of applying a resin solution containing the thermoplastic polyimide as a main component to a heat-resistant film when the thermoplastic polyimide is soluble, followed by drying; A method of drying and imidizing after applying to a heat-resistant film;
And the like.

At the stage where the heat-resistant film is a gel film, an adhesive layer mainly composed of thermoplastic polyimide may be formed on the gel film. Among these, in view of the adhesiveness between the heat-resistant film and the adhesive layer, a method of applying a polyamic acid-based solution to the heat-resistant film, followed by drying and thermally imidizing to laminate. Particularly preferred. Also, when thermally imidizing as described above,
It is preferable to imidize 90 mol% or more of the polyamic acid using a far infrared ray furnace.

Although the molecular weight of the thermoplastic polyimide is not particularly limited, the number average molecular weight is preferably 50,000 or more, and 80,000, so that the adhesive strength and strength of the adhesive layer can be maintained. More preferably, it is more preferably 100,000 or more.

The molecular weight of the thermoplastic polyimide or polyamic acid (solution) can be measured by GPC (gel permeation chromatography). Next, a method of laminating a copper foil using an adhesive film having an adhesive layer formed on both surfaces or one surface of a heat-resistant film will be described.

Specifically, for example, a copper foil with a carrier and an adhesive film are heated and pressed by a hot roll machine having at least a pair of heating rolls or a double belt press machine having a pair of endless belts, and after cooling or during cooling. A method of peeling the carrier is used. The bonding temperature of the adhesive film develops (the glass transition temperature or higher)
In addition, the heating may be performed under conditions that allow the carrier to be peeled off after heating and pressure bonding. The most preferred temperature range is + 50 ° C to + 100 ° C of the glass transition temperature of the adhesive layer. The pressing time of the copper foil depends on the temperature at the time of pressing, but is preferably within 5 minutes, particularly preferably within 3 minutes. Further, the pressure for pressing is preferably 30 kg / cm or more in terms of linear pressure.
It is particularly preferred that it is at least kg / cm.

Although one embodiment of the copper-clad laminate according to the present invention has been described, the present invention is not limited to this embodiment at all, and should be understood by those skilled in the art without departing from the spirit thereof. Based on this, various modifications, changes, and modifications can be made. Hereinafter, the present invention will be described more specifically with reference to examples.

[0055]

EXAMPLES The glass transition temperatures of the adhesive layers in the following Examples and Comparative Examples were measured using the methods described below. And the adhesive strength of the metal foil laminated board obtained in the following Examples and Comparative Examples was measured using the method described below.

(Glass Transition Temperature of Adhesive Layer) Using DMS-200 manufactured by Seiko Denshi Kogyo Co., Ltd., the measurement sample was placed in dry air, and the storage elastic modulus was determined in the temperature range of 20 ° C. to 400 ° C. ε ′) was measured, and the inflection point was taken as the glass transition temperature of the sample. As a measurement sample, an adhesive film slit to a width of 9 mm and a length of 40 mm or a single film of an adhesive layer was used. The measurement was performed with a measurement length (measurement jig interval) of 20 mm.

(Adhesive strength of metal foil laminate) The measurement was performed using an autograph manufactured by Shimadzu Corporation. Partially etched copper clad laminate, 5m wide on adhesive film
A copper pattern having a length of 80 mm and a length of 80 mm was formed and used as a measurement sample. Peel off the end of the copper pattern from the interface between the heat-resistant film and the adhesive layer, and fix the end to the jig for measurement.
The pattern was peeled off at an angle of 180 ° at a speed of 50 mm / min, and the strength was measured.

The method for producing the resin solution for the adhesive layer used in Examples 1 and 2 is described below.

1. Example of Production of Resin Solution A-1 for Adhesive Layer The whole system was cooled with ice water, and 2,2′-bis [4- (4
-Aminophenoxy) phenyl] propane (hereinafter BA
It is called PP. ) 123.1 g and 747.3 g of dimethylformamide (hereinafter, referred to as DMF) were added and stirred for 15 minutes.

Next, 3,3 ', 4,4'
-119.0 g of ethylene glycol dibenzoate tetracarboxylic dianhydride (hereinafter referred to as TMEG)
It was dissolved in 40 g of DMF and added, followed by stirring for 30 minutes. 3
After stirring for 0 minutes, another 4.1 g of TMEG was added to DMF3.
The solution dissolved in 6.9 g was gradually poured in while paying attention to the viscosity of the solution in the flask, and then left for 1 hour with stirring to obtain a thermoplastic polyimide layer having a solid content of 23% as a resin solution for the adhesive layer. Acid solution for use (A-1)
I got

[0061] 2. Production Example of Adhesive Layer Resin Solution A-2 In the same manner as in Production Example A-1, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and BAPP are used in a molar ratio of 1/1. By polymerizing, a polyamic acid is synthesized, and the solid content concentration is 23 as a resin solution for the adhesive layer.
% Of a polyamic acid solution for a thermoplastic polyimide layer (A-
2) was obtained.

(Example 1) An adhesive resin solution A was applied to an Apical HP (17 μm thick) (heat-resistant film) manufactured by Kanegabuchi Chemical Industry Co., Ltd. using a roll coater so that the thickness of the adhesive layer became 4 μm after drying and imidization. -1
Dry at 00 ° C. for 4 minutes. The other side was similarly coated with the adhesive resin solution and dried to obtain a film having an adhesive layer which was semi-dried on both sides. The resulting film was passed through a far-infrared furnace heated to an ambient temperature of 300 ° C. for 2 minutes to obtain an adhesive film having a total thickness of 25 μm having a 4 μm adhesive layer on both sides of a 17 μm heat-resistant film.

The glass transition temperature of the resulting adhesive film was 170 ° C. On both sides of this adhesive film, Mitsui Kinzoku Kogyo Co., Ltd.
After placing a thin (5 μm thick copper foil with a carrier and a 35 μm thick copper foil with a carrier) copper foil, the temperature was 280 ° C. and the linear pressure was 7 in a double belt press.
The laminate was obtained by thermocompression bonding at 0 kg / cm for 3 minutes. After cooling, the copper foil for carrier was peeled off, and the structure was changed to copper foil (5 μm
Thickness) / adhesive layer (4 μm thickness) / heat-resistant film (17 μm)
m) / adhesive layer (4 μm) / copper foil (5 μm). The adhesive strength of this copper clad laminate was measured and is shown in Table 1 below. As shown in Table 1, the obtained copper-clad laminate was
It had an adhesive strength of 1.0 kgf / cm.

(Example 2) The adhesive resin solution A-1 was mixed with A-
In place of Example 2, an adhesive film was obtained in the same manner as in Example 1. The glass transition temperature of the adhesive layer measured using the obtained adhesive film was 240 ° C. On both sides of this adhesive film, Mitsui Kinzoku Kogyo Co., Ltd.
After placing the copper foil of microThin, the laminate was heat-pressed with a double belt press at a temperature of 280 ° C. and a linear pressure of 70 kg / cm for 3 minutes to obtain a laminate. After cooling, the copper foil for the carrier was peeled off, and the composition was copper foil (5 μm thick) / adhesive layer (4
μm thickness) / heat-resistant film (17 μm) / adhesive layer (4 μm)
m) / copper foil (5 μm) laminate. The adhesive strength of this copper clad laminate was measured and is shown in Table 1. As shown in Table 1, the obtained copper-clad laminate had an adhesive strength of 1.0 kgf / cm.

[0065]

[Table 1] (Comparative Example 1) Preparation of Resin Solution for Heat Resistant Film Polyamic acid is obtained by polymerizing pyromellitic dianhydride / 4,4′-diaminobenzanilide / 4,4′-diaminodiphenyl ether at a molar ratio of 5/4/1. Synthesized.

2. Production of Copper-Clad Laminate After applying the above resin solution for a heat-resistant film to the same MicroThin as in Example 1 above using a die coater,
10 minutes at 100 ° C, 10 minutes at 200 ° C, 10 minutes at 300 ° C
After drying at 400 ° C. for 10 minutes and imidizing, a copper-clad laminate having a structure of copper foil for carrier (35 μm) / copper foil (5 μm) / heat-resistant film (17 μm) was obtained. However, the copper foils were stuck together and the carrier copper foil could not be peeled off.

[0067]

As described above, by heating and pressing a metal foil with a carrier on a heat-resistant film via an adhesive layer mainly composed of a thermoplastic polyimide resin, the adhesiveness and the moisture absorption characteristics are excellent. Thus, it is possible to obtain a copper-clad laminate having a thin copper foil layer, which is suitable for use in novel high-density packaging materials such as FPC and rigid-flex substrate materials having excellent heat resistance, COF and LOC packages, and MCM.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kosuke Kataoka 2-4-64 Sakamoto, Otsu-shi, Shiga (72) Inventor Hiroyuki Furuya 1-10-6-412 Kamitsumuro, Takatsuki-shi, Osaka F-term (reference) 4F100 AB17A AB33A AK01C AK49B AK49C BA03 BA10A BA10C EC051 EH461 EJ182 EJ303 EJ422 EJ861 EJ911 GB43 JA05B JA20A JB16B JJ03C JL11B YY00A YY00B

Claims (9)

[Claims] 1. A copper-clad laminate comprising a copper foil having a thickness of 1 to 8 μm, an adhesive layer mainly composed of a thermoplastic polyimide resin, and a heat-resistant film. 2. The copper-clad laminate according to claim 1, wherein the heat-resistant film is a polyimide film. 3. The copper clad laminate according to claim 1, wherein the adhesive layer has a glass transition temperature of 150 ° C. to 250 ° C. 4. A method for producing a copper-clad laminate provided with a copper foil having a thickness of 1 to 8 μm, comprising: forming an adhesive layer on a heat-resistant film; copper foil with a carrier on the surface of the adhesive layer A step of heating and pressing the obtained laminate to bond the adhesive layer in the laminate to the copper foil with a carrier; and a step of peeling off the carrier. 5. The method according to claim 4, wherein the step of bonding is performed at a temperature 50 ° C. to 100 ° C. higher than a glass transition temperature of the bonding layer. 6. A copper-clad laminate comprising a copper foil having a thickness of 1 to 8 μm, an adhesive layer mainly composed of a thermoplastic polyimide resin, and a heat-resistant film, wherein the adhesive layer is formed on the heat-resistant film. Forming; placing copper foil with a carrier on the surface of the adhesive layer; heating and pressing the obtained laminate to bond the adhesive layer in the laminate with the copper foil with a carrier; A copper-clad laminate manufactured by a method including a peeling step. 7. The copper clad laminate according to claim 6, wherein the bonding step is performed at a temperature higher by 50 ° C. to 100 ° C. than a glass transition temperature of the bonding layer. 8. The copper clad laminate according to claim 6, wherein the heat resistant film is a polyimide film. 9. The copper clad laminate according to claim 6, wherein the adhesive layer has a glass transition temperature of 150 ° C. to 250 ° C.