JP5042728B2 - Method for modifying surface of polyimide resin layer and method for producing metal-clad laminate - Google Patents

Description

  The present invention relates to a surface treatment method for a polyimide resin layer and a method for producing a metal-clad laminate in which a polyimide resin layer is laminated on a metal foil, and more specifically, a surface treatment method for a polyimide resin layer suitable for a printed wiring board and The present invention relates to a method for producing a metal-clad laminate.

  In an electronic circuit of an electronic device, a printed wiring board obtained by processing a laminated board made of an insulating material and a conductive material is used. A printed wiring board is formed by fixing a conductive pattern based on electrical design on the surface (and inside) of an insulating substrate with a conductive material. It is roughly divided into a board and a flexible printed wiring board which is rich in flexibility. The flexible printed wiring board is characterized by having flexibility, and is a necessary part for connection in a movable part that constantly bends. In addition, since the flexible printed wiring board can be stored in a bent state in an electronic device, it is also used as a space-saving wiring material. In a flexible substrate as a material for a flexible printed wiring board, polyimide ester or polyimide resin is often used as an insulating resin as a base material, but the amount of heat-resistant polyimide resin is overwhelmingly large. On the other hand, copper foil is generally used as the conductive material from the viewpoint of conductivity.

  The flexible substrate includes a three-layer flexible substrate and a two-layer flexible substrate because of its structure. A three-layer flexible substrate is made by bonding a base film such as polyimide and a copper foil with an adhesive such as an epoxy resin or an acrylic resin to form a base film layer (main layer of an insulating resin layer), an adhesive layer, and a copper foil layer. It is a laminated board composed of layers. On the other hand, the two-layer flexible substrate is a laminated board composed of two layers, a base film layer and a copper foil layer, using a special construction method without using an adhesive. Since the two-layer flexible substrate does not include an adhesive layer with low heat resistance such as an epoxy resin or an acrylic resin, the two-layer flexible substrate has high reliability, and the entire circuit can be thinned, and the amount of use is increasing. On the other hand, from a different viewpoint, the base film layer of the flexible substrate is desired to have a low thermal expansion coefficient in order to prevent curling, but a polyimide resin having a low thermal expansion coefficient is inferior in adhesiveness. When using all the polyimide resin without using an adhesive, it was necessary to provide a good adhesion polyimide resin layer as an adhesion-imparting layer on the adhesive surface side. A flexible substrate having a copper foil layer on both sides is also known. After manufacturing a single-sided flexible substrate having a copper foil layer on one side, a method of stacking two flexible substrates on top of each other or copper on a single-sided flexible substrate A method of laminating and stacking foils is known. Also in this case, a flexible substrate that does not include an adhesive layer or an adhesion-imparting layer is desired.

  In recent years, there is an increasing demand for higher performance and higher functionality in electronic devices, and accordingly, higher density of printed wiring boards, which are circuit board materials used in electronic devices, is desired. In order to increase the density of the printed wiring board, it is necessary to reduce the width and interval of the circuit wiring, that is, to achieve a fine pitch. For this reason, in order to increase the density and fine pitch of a printed wiring board, it has been desired to use a copper foil having a low surface roughness. However, a copper foil having a low surface roughness has a small anchoring effect, that is, the biting of the insulating resin layer into the irregularities on the surface of the copper foil, so that the mechanical adhesive strength cannot be obtained, and therefore the adhesive strength to the insulating resin is low. There was a problem. Therefore, it is an issue to increase the adhesive force between the copper foil having a low surface roughness and the insulating resin.

  Polyimide resins are generally known to have poor adhesion. In addition, the base film layer of the laminate used for the printed wiring board is desired to be a polyimide resin layer having a low thermal expansion coefficient in order to prevent the occurrence of curling. There are conflicting relationships. In order to improve the adhesive strength, various surface modification techniques for polyimide films have been reported. As an example, there is a surface modification method by plasma treatment, but there is a problem that an expensive apparatus is required and a running cost is increased. Examples of the method for modifying the surface of a polyimide film by plasma treatment include, for example, JP-A-5-222219, JP-A-8-12779, JP-A-11-209488, JP-A-2004-51712, JP-A-2006. Specific examples are disclosed in Japanese Patent Publication No. 7518. However, in these conventional technologies, the adhesive force between the copper foil having a low surface roughness and the polyimide resin layer is not satisfactory.

  In addition, a surface modification method by wet etching, which is advantageous in terms of cost, is attracting attention, but in general, adhesion is not sufficient as compared with a surface modification method by dry etching such as plasma treatment, so this point is further improved. There was a need for improvement. As such a surface modification method by wet etching, for example, JP-A-11-49880 can be cited. According to this, a method of thermocompression bonding between a polyimide treated in a polar solvent containing an aliphatic primary amine and a metal via a polyimide adhesive is disclosed. However, this method has a problem that it is necessary to provide a polyimide adhesive layer, and the insulating resin layer becomes thick.

JP-A-5-222219 Japanese Patent Laid-Open No. 8-12779 JP-A-11-209488 JP 2004-51712 A JP 2006-7518 A JP 11-49880 A

  An object of the present invention is to improve the adhesion by modifying the surface of a polyimide resin layer. In addition, the surface of a low thermal expansion polyimide resin layer suitable as a base film layer is modified to improve adhesiveness, and the adhesive polyimide resin layer or adhesive layer that becomes an adhesion-imparting layer can be omitted. Objective. Another object is to provide a method for producing a copper clad laminate having an extremely thin adhesive layer, and to ensure that the insulating resin layer is extremely thin while ensuring sufficient adhesive strength to meet the fine pitch of printed circuit boards. It aims at providing the manufacturing method of the copper clad laminated board which can respond also to this. Another object of the present invention is to improve an adhesion method in which polyimide resin layer surfaces are superposed and thermocompression bonded. Another object is to provide a method for producing a double-sided metal-clad laminate.

  In order to achieve the above object, the present inventors have studied, and by appropriately improving the wet etching method, the polyimide resin layer using the wet etching method has almost no change in the thickness of the polyimide resin layer. The present inventors have found that an excellent adhesive polyimide resin layer having a high adhesive strength with a metal foil can be provided.

The present invention includes: a) a step of treating the surface of the polyimide resin layer with an aqueous alkali solution to form an alkali treated layer; and b) two primary amino groups on the surface of the alkali treated layer. Impregnating and drying a polar solvent solution containing an aromatic amino compound composed of a substituted aromatic diamine to form an aromatic amino compound-containing layer; and c) imidizing and modifying the aromatic amino compound-containing layer. And a step of forming an imidized layer. A method for forming a modified layer on a surface of a polyimide resin layer.

The present invention also includes: a) a step of forming a surface of the polyimide resin layer with an aqueous alkali solution to form an alkali-treated layer; and b) two primary amino groups are aromatic on the surface of the alkali-treated layer. Impregnating and drying a polar solvent solution containing an aromatic amino compound composed of an aromatic diamine substituted on a ring to form an aromatic amino compound-containing layer; and c) imidizing the aromatic amino compound-containing layer. A method for producing a metal-clad laminate, comprising: a step of forming a modified imidized layer; and d) a step of forming a metal layer on the surface of the modified imidized layer.

  Here, the thickness of the alkali treatment layer is preferably in the range of 0.005 to 3.0 μm. The aromatic amino compound is preferably an aromatic amine having a primary or secondary amino group. Furthermore, it is preferable that a polyimide resin layer is a polyimide resin layer which forms the surface layer of a laminated body, or is a polyimide resin layer which forms the surface layer of a polyimide resin film.

  In the method for producing a metal-clad laminate, as a step of forming a metal layer on the surface of the modified imidized layer, d1) a step of overlaying a metal foil on the surface of the modified imidized layer and thermocompression bonding, or d2) It preferably comprises a step of forming a metal thin film layer on the surface of the modified imidized layer. Moreover, copper foil, copper alloy foil, or stainless steel foil is suitable as the metal foil used in the process of superimposing the metal foils and thermocompression bonding.

  Hereinafter, the present invention will be described in detail.

  The polyimide resin layer used in the present invention is not particularly limited, and may be a film (sheet) made of polyimide resin, and is a polyimide laminated on a substrate such as a copper foil, a glass plate, or a resin film. It may be a resin layer. The base material here refers to a sheet-like resin or metal foil on which a polyimide resin layer is laminated. However, at least one surface of the polyimide resin layer exists as a surface layer. The thickness of the polyimide resin layer is in the range of 3 to 100 μm, preferably 3 to 50 μm. By performing surface treatment, the polyimide resin layer has at least two layers of an initial polyimide resin layer (unmodified polyimide resin layer) and a modified layer.

  Examples of the polyimide resin that forms the polyimide resin layer include heat-resistant resins having an imide group in the structure such as polyamide imide, polybenzimidazole, polyimide ester, polyether imide, and polysiloxane imide, including so-called polyimide resins. Moreover, a commercially available polyimide resin or a polyimide film can also be used conveniently.

Among the polyimide resin layers, the method of the present invention is suitable for a polyimide resin layer having low adhesion and low thermal expansion. Specifically, the thermal expansion coefficient is 1 × 10 ⁻⁶ to 30 × 10 ⁻⁶ (1 / K), preferably 1 × 10 ^{−6 to} 25 × 10 ⁻⁶ (1 / K), more preferably 15 ×. When applied to a low thermal expansion polyimide resin layer of 10 ^{−6 to} 25 × 10 ⁻⁶ (1 / K), a great effect is obtained. However, it can also be applied to a polyimide resin layer that exceeds the thermal linear expansion coefficient, and improves adhesion.

但し、Ar₁は式(3)又は式(4)で表される4価の芳香族基を示し、Ar₃は式(5)又は式(6)で表される2価の芳香族基を示し、R₁は独立に炭素数1〜6の1価の炭化水素基又はアルコキシ基を示し、X及びYは独立に単結合又は炭素数1〜15の2価の炭化水素基、O、S、CO、SO、SO₂若しくはCONHから選ばれる2価の基を示しnは独立に0〜4の整数を示し、qは構成単位の存在モル比を示し、0.1〜1.0の範囲である。 As a polyimide resin used for a polyimide resin layer, the polyimide resin which has a structural unit represented by General formula (1) is preferable.

However, Ar ₁ represents a tetravalent aromatic group represented by Formula (3) or Formula (4), and Ar ₃ represents a divalent aromatic group represented by Formula (5) or Formula (6). R ₁ independently represents a monovalent hydrocarbon group or alkoxy group having 1 to 6 carbon atoms, X and Y independently represent a single bond or a divalent hydrocarbon group having 1 to 15 carbon atoms, O, S Represents a divalent group selected from CO, SO, SO ₂ or CONH, n independently represents an integer of 0 to 4, q represents the molar ratio of the constituent units, and ranges from 0.1 to 1.0.

  The structural unit may be present in the homopolymer or may be present as a structural unit of the copolymer. In the case of a copolymer having a plurality of structural units, it may exist as a block or may exist randomly. Among the polyimide resins having such a structural unit, a polyimide resin that can be suitably used is a non-thermoplastic polyimide resin.

Since a polyimide resin is generally produced by reacting a diamine and an acid anhydride, a specific example of the polyimide resin can be understood by explaining the diamine and the acid anhydride. In the above general formula (1), Ar ₃ can be referred to as a diamine residue, and Ar ₁ can be referred to as an acid anhydride residue. Therefore, a preferred polyimide resin will be described using a diamine and an acid anhydride. However, it is not limited to the polyimide resin obtained by this method.

Examples of the diamine include 4,4′-diaminodiphenyl ether, 2′-methoxy-4,4′-diaminobenzanilide, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-amino). Phenoxy) benzene, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'- Preferred examples include diaminobiphenyl and 4,4′-diaminobenzanilide.
Also, 2,2-bis- [4- (3-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy)] biphenyl, bis [4- (3-aminophenoxy) biphenyl, bis [1- (4-aminophenoxy)] biphenyl, bis [1- (3-aminophenoxy)] biphenyl, Bis [4- (4-aminophenoxy) phenyl] methane, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] ether, bis [4- (3-amino Phenoxy) phenyl] ether, bis [4- (4-aminophenoxy)] benzophenone, bis [4- (3-aminophenoxy)] benzophenone, bis [4,4 ′-(4-aminophenoxy)] benzanilide, bis [ Four, 4 ′-(3-aminophenoxy)] benzanilide, 9,9-bis [4- (4-aminophenoxy) phenyl] fluorene, 9,9-bis [4- (3-aminophenoxy) phenyl] fluorene and the like are preferable. Can be mentioned.

  Other diamines include 2,2-bis- [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis- [4- (3-aminophenoxy) phenyl] hexafluoropropane, 4,4 '-Methylenedi-o-toluidine, 4,4'-methylenedi-2,6-xylidine, 4,4'-methylene-2,6-diethylaniline, 4,4'-diaminodiphenylpropane, 3,3'-diamino Diphenylpropane, 4,4'-diaminodiphenylethane, 3,3'-diaminodiphenylethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 3,3 ' -Diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,3-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, benzidine, 3, 3'-di Minobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxybenzidine, 4,4 ''-diamino-p-terphenyl, 3,3 ''-diamino-p-ter Phenyl, m-phenylenediamine, p-phenylenediamine, 2,6-diaminopyridine, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4'- [1,4-phenylenebis (1-methylethylidene)] bisaniline, 4,4 '-[1,3-phenylenebis (1-methylethylidene)] bisaniline, bis (p-aminocyclohexyl) methane, bis (p- β-amino-t-butylphenyl) ether, bis (p-β-methyl-δ-aminopentyl) benzene, p-bis (2-methyl-4-aminopentyl) benzene, p-bis (1,1-dimethyl) -5-aminopentyl) benzene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4-bis (β-amino-t-butyl) toluene 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m-xylylenediamine, p-xylylenediamine, 2,6-diaminopyridine, 2, Examples include 5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine and the like.

Examples of the acid anhydride include pyromellitic anhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride, Preferred is 4,4′-oxydiphthalic anhydride.
Also, 2,2 ', 3,3'-, 2,3,3', 4'- or 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 2,3', 3,4 '-Biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, 2,3 ', 3,4'-diphenyl ether tetracarboxylic dianhydride, bis (2, Preferable examples include 3-dicarboxyphenyl) ether dianhydride. Also 3,3``, 4,4 ''-, 2,3,3``, 4 ''-or 2,2 '', 3,3 ''-p-terphenyltetracarboxylic dianhydride 2,2-bis (2,3- or 3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3- or 3.4-dicarboxyphenyl) methane dianhydride, bis (2,3- Alternatively, 3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3- or 3,4-dicarboxyphenyl) ethane dianhydride and the like are preferable.

  Other acid anhydrides include 1,2,7,8-, 1,2,6,7- or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6,7- Anthracene tetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) tetrafluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 2,3,6,7- Naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,8-dimethyl-1,2, 3,5,6,7-Hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 2,6- or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic acid Dianhydride, 2,3,6,7- (or 1,4,5,8-) tetrachloronaphthalene-1,4,5,8- (or 2,3,6,7-) tetracarboxylic acid di Anhydride, 2,3,8,9-, 3,4,9,10-, 4,5,10,11- or 5,6,11,12-perylene-tetracarboxylic dianhydride, cyclopentane- 1,2,3,4-tetracar Boronic acid dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5- Examples thereof include tetracarboxylic dianhydride, 4,4-bis (2,3-dicarboxyphenoxy) diphenylmethane dianhydride and the like.

  Each of the diamine and acid anhydride may be used alone or in combination of two or more. Also, other diamines and acid anhydrides not included in the general formula (1) can be used together with the above diamine or acid anhydride. In this case, the usage ratio of the other diamine or acid anhydride is 90 mol. % Or less, preferably 50 mol% or less. Control the thermal expansion, adhesiveness, glass transition point (Tg), etc. by selecting the type of diamine and acid anhydride, and the molar ratios when using two or more diamines or acid anhydrides. be able to.

  The method for producing the polyimide resin layer is not particularly limited. For example, after applying a polyamic acid resin solution, which is a polyimide resin precursor, on the substrate, it is dried and imidized to form the polyimide resin layer on the substrate. There is a way. The method for applying the polyamic acid resin solution on the substrate is not particularly limited, and it can be applied by a coater such as a comma, a die, a knife, or a lip.

  Moreover, the method of drying and imidation is not particularly limited, and for example, heat treatment such as heating for 1 to 60 minutes at a temperature of 80 to 400 ° C. is suitably employed. By performing such heat treatment, dehydration and ring closure of the polyamic acid proceeds, so that a polyimide resin layer can be formed on the substrate. The polyimide resin layer in which the polyimide resin layer is formed on the substrate may be used as it is, or may be used after being peeled off.

  The polyimide resin layer may be formed of only a single layer or may be formed of a plurality of layers. In the case where a plurality of polyimide resin layers are used, other polyimide resins can be sequentially formed on a polyimide resin layer made of different components. When the polyimide resin layer is composed of three or more layers, the polyimide resin having the same configuration may be used twice or more. Two layers or a single layer, in particular a single layer, having a simple layer structure can be advantageously obtained industrially. The polyimide resin layer has a thickness of 3 to 100 μm, preferably 3 to 50 μm.

  In the method for forming a modified layer on the surface of the polyimide resin layer of the present invention, a) a step of forming an alkali treatment layer by treating the surface side of the polyimide resin layer with an aqueous alkali solution (step a), b) Impregnating and drying a polar solvent solution containing an aromatic amino compound on the surface of the alkali-treated layer to form an aromatic amino compound-containing layer (step b), and c) imidizing the aromatic amino compound-containing layer And a step of forming a modified imidized layer (step c). The method for producing a metal-clad laminate of the present invention includes d) a step of forming a metal layer on the surface of the modified imidized layer (step d) in addition to the above steps a, b and c.

  In the method for forming a modified layer and the method for producing a metal-clad laminate of the present invention, step a, step b, and step c can be performed in the same manner regardless of the case. First, the common process a, process b, and process c will be described.

  In step a, the surface layer of the polyimide resin layer is treated with an alkaline aqueous solution to form an alkali-treated layer. As the alkaline aqueous solution, it is preferable to use an alkaline aqueous solution of sodium hydroxide or potassium hydroxide having a liquid temperature of 0.5 to 50 wt% and a liquid temperature of 5 to 80 ° C., and dipping, spraying, brushing, etc. can be applied. it can. For example, when applying the dipping method, it is effective to perform the treatment for 10 seconds to 60 minutes. Preferably, the treatment is performed for 30 seconds to 10 minutes with an alkaline aqueous solution of 1 to 30 wt% and a liquid temperature of 25 to 60 ° C. Depending on the structure of the polyimide resin layer, the processing conditions can be appropriately changed. In general, when the concentration of the alkaline aqueous solution is low, the surface treatment time of the polyimide resin layer becomes long. Further, when the temperature of the alkaline aqueous solution increases, the processing time is shortened. When the treatment is performed with the alkaline aqueous solution, the alkaline aqueous solution penetrates from the surface side of the polyimide resin layer, and the polyimide resin layer is alkali-treated. This alkali treatment reaction is considered to be mainly hydrolysis of imide bonds. The thickness of the alkali-treated layer formed by the alkali treatment is in the range of 1/200 to 1/2, preferably 1/100 to 1/5 of the polyimide resin layer thickness. Moreover, from another viewpoint, 0.005-3.0 micrometers, Preferably it is 0.05-2.0 micrometers, More preferably, 0.1-1.0 micrometer is good. By setting the thickness within such a range, it is advantageous for thermocompression bonding of the metal foil. From another viewpoint, the thickness is 0.005 to 0.1 μm, preferably 0.01 to 0.1 μm, and more preferably 0.05 to 0.1 μm. By setting the thickness within such a range, it is advantageous for forming a metal thin film. When the thickness of the alkali treatment layer is out of the above range, sufficient adhesion strength between the polyimide resin layer and the metal layer is hardly exhibited. When the polyimide resin layer is a polyimide resin film, both surfaces may be modified at the same time.

  In the alkali-treated layer formed by the alkali treatment, a salt of an alkali metal and a carboxyl group at the end of the polyimide resin due to the aqueous alkali solution may be formed, and therefore it is preferable to wash with an acid aqueous solution. . Any aqueous solution can be used as long as it is acidic. In particular, an aqueous hydrochloric acid solution or an aqueous sulfuric acid solution is preferable. Further, the concentration is preferably in the range of 0.5 to 50 wt%, but preferably in the range of 0.5 to 5 wt%. More preferably, the pH is 2 or less. Then, after washing with water, it is good to dry and use for the process b.

  In step b, the surface of the alkali-treated layer is impregnated with a polar solvent solution containing an aromatic amino compound and dried to form an aromatic amino compound-containing layer.

The aromatic amino compound is preferably an aromatic amine having a primary or secondary amino group, particularly an aromatic amine in which the primary amino group is substituted with an aromatic ring. The number of amino groups is 1-5, preferably 1-3, more preferably 2. The molecular weight of the aromatic amino compound is 90 to 1000, preferably 100 to 600, and more preferably 110 to 500. Examples of the aromatic amino compound include compounds having at least 1, preferably 1 to 10, and preferably 1 to 4 aromatic rings. The aromatic ring is substituted with a substituent other than an amino group. It may or may not be. As the substituent other than the amino group, those having a functional group capable of condensation polymerization with a terminal carboxyl group present in the alkali-treated layer, such as a hydroxyl group and a mercapto group are preferable. Examples of the aromatic ring include condensed rings such as a benzene ring and a naphthalene ring. Compounds having a plurality of aromatic rings include Ar-X-Ar, Ar-Y-Ar-X-Ar-Y-Ar (where Ar is an aromatic ring such as a benzene ring) in addition to a biphenyl ring, etc. , X and Y are independently compounds in which an amino group is substituted on a divalent group such as CO, O, S, SO, SO ₂ , CONH and C _n H _2n ). Examples of the substituent other than the amino group include a branched or straight chain alkyl group having 1 to 18 carbon atoms (for example, methyl, ethyl, propyl, etc.), and an aromatic group having 6 to 13 carbon atoms (for example, , Phenyl), an arylalkyl group having 7 to 12 carbon atoms (for example, benzyl) and the like. Hydroxyl groups can also be used as aromatic ring substituents. An example of a compound having an aromatic ring substituted with a hydroxyl group is aminophenol. Furthermore, a condensed ring system having 10 to 20 carbon atoms can be used as the aromatic amine group-containing compound of the present invention. One example of a fused ring system that can be used in the present invention is diaminonaphthalene.

  Although the specific example of an aromatic amino compound is shown next, it is not restricted to this. One or more aromatic amino compounds can be used.

  Aniline, toluidine, aminonaphthalene, aminobiphenyl, 2,2-bis- [4- (4-aminophenoxy) phenyl] propane, 2,2-bis- [4- (3-aminophenoxy) phenyl] propane, bis [ 4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy)] biphenyl, bis [4- (3-aminophenoxy) biphenyl Bis [1- (4-aminophenoxy)] biphenyl, bis [1- (3-aminophenoxy)] biphenyl, bis [4- (4-aminophenoxy) phenyl] methane, bis [4- (3-aminophenoxy) ) Phenyl] methane, bis [4- (4-aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy)] benzophenone Bis [4- (3-aminophenoxy)] benzophenone, bis [4,4 '-(4-aminophenoxy)] benzanilide, bis [4,4'-(3-aminophenoxy)] benzanilide, 9,9-bis [4- (4-aminophenoxy) phenyl] fluorene, 9,9-bis [4- (3-aminophenoxy) phenyl] fluorene, 2,2-bis- [4- (4-aminophenoxy) phenyl] hexafluoro Propane, 2,2-bis- [4- (3-aminophenoxy) phenyl] hexafluoropropane, 4,4'-methylenedi-o-toluidine, 4,4'-methylenedi-2,6-xylidine, 4,4 '-Methylene-2,6-diethylaniline, 4,4'-diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 4,4'-diaminodiphenylethane, 3,3'-diaminodiphenylethane, 4,4 '-Diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diamino Phenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,3-diaminodiphenyl ether, 3,4'- Diaminodiphenyl ether, benzidine, 3,3'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxybenzidine, 4,4 ''-diamino-p-terphenyl, 3 , 3 ''-Diamino-p-terphenyl, m-phenylenediamine, p-phenylenediamine, 2,6-diaminopyridine, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4- Aminophenoxy) benzene, 4,4 '-[1,4-phenylenebis (1-methylethylidene)] bisaniline, 4,4'-[1,3-phenylenebis (1-methylethylidene)] bisaniline, bis (p -Aminocyclohexyl) methane, bis (p-β-amino) Tert-butylphenyl) ether, bis (p-β-methyl-δ-aminopentyl) benzene, p-bis (2-methyl-4-aminopentyl) benzene, p-bis (1,1-dimethyl-5 -Aminopentyl) benzene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4-bis (β-amino-t-butyl) toluene, 2,4-diaminotoluene, m-xylene-2,5 -Diamine, p-xylene-2,5-diamine, m-xylylenediamine, p-xylylenediamine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4 -Oxadiazole, piperazine and the like can be mentioned.

  The aromatic amino compound is used as a solution in a polar solvent. The polar solvent is not particularly limited as long as it dissolves an aromatic amino compound. For example, water or alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, dimethyl ketone and methyl ethyl ketone, ethers such as tetrahydrofuran, or tertiary amines such as N-methylpyrrolidone, dimethylacetamide and dimethylformamide And dimethyl sulfoxide. These may be used alone, or may be used by mixing several kinds thereof, or may be mixed with water. Preferably, it is methanol.

  The concentration of the polar solvent solution containing the aromatic amino compound is 0.0001 to 1M (0.0001 to 1 mol / L), preferably 0.0005 to 0.1M, more preferably as the concentration of the aromatic amino compound. It is appropriate to use a solution having a concentration of 0.0005 to 0.01M.

  If the concentration of the aromatic amino compound is high, the amount of the aromatic amino compound solution not only impregnates the alkali treatment layer but also adheres to the surface of the alkali treatment layer, so that a high concentration is not desirable.

  The impregnation method is not particularly limited as long as it can be brought into contact with a solution of a polar solvent containing an aromatic amino compound on the surface of the alkali treatment layer, and a known method can be used. For example, a dipping method, a spray method, a brush coating method or a printing method can be used. The temperature may be 0 to 100 ° C., preferably 10 to 40 ° C. Moreover, as for the impregnation time, when applying the dipping method, it is effective to treat for 30 seconds to 1 hour, preferably 1 to 15 minutes.

  Dry after impregnation. The drying method is not particularly limited, and natural drying, spray drying with an air gun, oven drying, or the like can be used. The drying conditions depend on the type of polar solvent, but are 10 to 150 ° C. for 5 seconds to 60 minutes, preferably 25 to 150 ° C. for 10 seconds to 30 minutes, and more preferably 30 to 120 ° C. for 1 minute to 10 minutes. For minutes.

  In this impregnation / drying treatment, a solution of a polar solvent containing an aromatic amino compound permeates into the alkali treatment layer surface to form an aromatic amino compound-containing layer. The thickness to penetrate, that is, the thickness of the aromatic amino compound-containing layer is 1/10 to 1.5 times, preferably 1/2 to 1.2 times, more preferably 0.8 to 1.2 times the thickness of the alkali treatment layer. Good. The polyimide resin layer obtained by drying becomes a surface-treated polyimide resin layer having a modified surface and improved adhesion.

  In step c, the aromatic amino compound-containing layer is imidized to form a modified imidized layer. Imidation can be either imidation by heating or chemical imidization using a catalyst, and is not limited. For example, when imidation by heating is performed, 100 to 400 ° C, preferably 150 to 400 ° C. It is preferable to completely imidize at a temperature of 1. In the case where imidization is insufficient, chemical imidization with a catalyst may be used in combination. In this imidization treatment, it is considered that a reaction in which an amino compound and a terminal carboxyl group present in a polyimide resin layer, particularly an alkali treatment layer react to imidize is the main. Accordingly, the polyimide resin having a low molecular weight and increased terminal carboxyl groups in step a is imidized in the state of low molecular weight in step c, and the terminal is stabilized, so that the adhesiveness of the polyimide resin layer is improved. It is thought to improve.

  In the method for forming a modified layer on the surface of the polyimide resin layer of the present invention, the thickness of the alkali-treated layer in step a is preferably in the range of 0.005 to 3.0 μm. The amino compound used in step b is preferably an aromatic amine having a primary or secondary amino group. And a polyimide resin layer may be a polyimide resin layer which forms the surface layer of a laminated body, and may be a polyimide resin layer which forms the surface layer of a polyimide resin film.

  Next, the details of the method for producing the metal-clad laminate of the present invention will be described. Step a, step b, and step c can be performed in the same manner as the method of forming the modified layer on the surface of the polyimide resin layer. A polyimide resin layer (hereinafter also referred to as a surface-treated polyimide resin layer) obtained by this method is subjected to step d. That is, in the method for producing a metal-clad laminate, in addition to step a, step b and step c, the step is applied to step d. In step d, a metal layer is formed. As this formation method, a method of forming a metal thin film by a thermocompression bonding method or vapor deposition is suitable. The thermocompression bonding method includes a step d1 in addition to the steps a, b, and c. The method for forming a metal thin film by vapor deposition or the like includes a step d2 in addition to the steps a, b and c.

  In step d1, the method for thermocompression bonding of the metal foil is not particularly limited, and a known method can be appropriately employed. Examples of the method of laminating the metal foil include a normal hydro press, a vacuum type hydro press, an autoclave pressurizing vacuum press, and a continuous thermal laminator. Among the methods of laminating metal foils, a vacuum hydropress and a continuous thermal laminator are used from the viewpoint that sufficient pressing pressure is obtained, residual volatiles can be easily removed, and oxidation of the metal foil can be prevented. It is preferable to use it.

  In thermocompression bonding, it is preferable to press the metal foil while heating in the range of 150 to 450 ° C. More preferably, it exists in the range of 150-400 degreeC. Furthermore, it is preferably in the range of 150 to 380 ° C. From another point of view, the temperature is preferably equal to or higher than the glass transition temperature of the polyimide resin layer or the modified imidized layer. The press pressure is usually about 1 to 50 MPa, although it depends on the type of press equipment used.

  As metal foil, iron foil, nickel foil, beryllium foil, aluminum foil, zinc foil, indium foil, silver foil, gold foil, tin foil, zirconium foil, stainless steel foil, tantalum foil, titanium foil, copper foil, lead foil, magnesium foil , Manganese foils and alloy foils thereof. Among these, copper foil (copper alloy foil) or stainless steel foil is suitable. The copper foil here means copper or a copper alloy foil containing copper as a main component. Preferably, the copper foil has a copper content of 90% by mass or more, particularly preferably 95% by mass or more. Examples of the metal contained in the copper foil include chromium, zirconium, nickel, silicon, zinc, and beryllium. An alloy foil containing two or more of these metals may also be used. Moreover, although there is no restriction | limiting in the material of stainless steel foil, For example, stainless steel foil like SUS304 is preferable.

  The metal foil may be treated with a silane coupling agent on the surface on which the polyimide resin layer is laminated. The silane coupling agent is preferably a silane coupling agent having a functional group such as an amino group or a mercapto group, more preferably a silane coupling agent having an amino group. Specific examples include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyl. Examples include trimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, and the like. Among these, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyl It may be at least one selected from dimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine and N-phenyl-3-aminopropyltrimethoxysilane. In particular, 3-aminopropyltriethoxysilane and / or 3-aminopropyltrimethoxysilane are preferable.

  The silane coupling agent is used as a polar solvent solution. As the polar solvent, water or a polar organic solvent containing water is suitable. The polar organic solvent is not particularly limited as long as it is a polar liquid having an affinity for water. Examples of such a polar organic solvent include methanol, ethanol, propanol, isopropanol, acetone, tetrahydrofuran, dimethylformamide, dimethylacetamide and the like. The silane coupling agent solution has a concentration of 0.01 to 5% by weight, preferably 0.1 to 2.0% by weight, more preferably 0.5 to 1.0% by weight.

  The silane coupling agent treatment is not particularly limited as long as it is a method in which a solution of a polar solvent containing a silane coupling agent contacts, and a known method can be used. For example, a dipping method, a spray method, a brush coating method or a printing method can be used. The temperature may be 0 to 100 ° C., preferably 10 to 40 ° C. Moreover, as for immersion time, when applying the immersion method, it is effective to process for 10 second-1 hour, Preferably it is 30 second-15 minutes. Dry after treatment. The drying method is not particularly limited, and natural drying, spray drying with an air gun, oven drying, or the like can be used. The drying conditions depend on the type of polar solvent, but are 10 to 150 ° C. for 5 seconds to 60 minutes, preferably 25 to 150 ° C. for 10 seconds to 30 minutes, more preferably 30 to 120 ° C. for 1 minute to 10 minutes. It is.

  An example in which the metal foil is a copper foil includes a case where the metal foil is used for a flexible substrate. The preferred thickness of the copper foil when used in this application is in the range of 3 to 50 μm, more preferably in the range of 5 to 30 μm, but the copper-clad laminate used in applications where fine pitch is required, A thin copper foil is preferably used, and in this case, a range of 5 to 20 μm is suitable. Moreover, since the adhesiveness with respect to a resin layer is acquired even if it uses copper foil with small surface roughness, this invention is suitable especially when using copper foil with small surface roughness. The preferred surface roughness of the copper foil is 10-point average roughness in the range of 0.1 to 3 μm. Particularly for copper foils used in applications requiring a fine pitch, a surface roughness of 10-point average roughness of 0.1 to 1.0 μm is suitable.

  As an example in which the metal foil is a stainless steel foil, there is a case where the metal foil is used for a suspension (hereinafter referred to as HDD suspension) mounted on a hard disk drive. The preferred thickness of the stainless steel foil when used for this purpose is in the range of 10 to 100 μm, more preferably in the range of 15 to 70 μm, and still more preferably in the range of 15 to 50 μm.

  The laminate obtained by this method for producing a metal-clad laminate is a laminate having a metal foil on one or both sides of a polyimide resin layer. The laminated board which has metal foil on one side is obtained by laminating | stacking metal foil on the surface treatment polyimide resin layer obtained by the surface treatment method of this invention. When the surface-treated polyimide resin layer is laminated on a substrate such as glass or a resin film, it is made a laminated plate and then peeled off from the substrate as necessary. When the surface-treated polyimide resin layer is laminated on a metal foil such as a copper foil, a double-sided metal-clad laminate can be obtained by laminating the metal foil on the polyimide resin layer side. Moreover, the metal clad laminated board which has metal foil on both surfaces is obtained by laminating | stacking metal foil on this both sides, when both surfaces of the surface treatment polyimide resin layer are surface-treated other than said method. Furthermore, after manufacturing a single-sided metal-clad laminate having a metal foil on one side, surface treatment of the polyimide resin layer is performed on at least one single-sided metal-clad laminate, It can also be manufactured by a method in which polyimide layers are superposed and thermocompression bonded.

  In this method for producing a metal-clad laminate, the alkali-treated layer preferably has a thickness in the range of 0.005 to 3.0 μm. The aromatic amino compound is preferably an aromatic amine having a primary or secondary amino group.

  Next, the manufacturing method of the metal-clad laminate of the present invention including the step d2 in addition to the steps a, b and c will be described. Steps a, b, and c are performed as described above, and are then applied to step d2. That is, a metal thin film layer is formed on the surface of the modified imidized layer in step c.

  In this method for producing a metal-clad laminate, the thickness of the alkali treatment layer is preferably in the range of 0.005 to 3.0 μm, more preferably 0.01 to 0.8 μm, and still more preferably 0.02 to 0.02 μm. 0.1 μm is preferable. Moreover, as an amino compound, the aromatic amine which has a primary or secondary amino group is preferable.

Although the method for forming the metal thin film layer is not particularly limited, for example, a vacuum evaporation method, a sputtering method, an electron beam evaporation method, an ion plating method, or the like can be used, and the sputtering method is particularly preferable. This sputtering method includes various methods such as DC sputtering, RF sputtering, DC magnetron sputtering, RF magnetron sputtering, EC sputtering, and laser beam sputtering, but is not particularly limited and can be appropriately employed. Regarding the conditions for forming the metal thin film layer by sputtering, for example, argon gas is used as the sputtering gas, and the pressure is preferably 1 × 10 ^{−2 to 1} Pa, more preferably 5 × 10 ^{−2 to} 5 × 10 ⁻¹ Pa. The sputtering power density is preferably 1 to 100 Wcm ⁻² , more preferably 1 to 50 Wcm ⁻² .

  For the formation of the metal thin film, copper is preferably used as the thin film layer. Under the present circumstances, the base metal thin film layer which improves adhesiveness more may be provided in a surface treatment polyimide resin layer, and a copper thin film layer may be provided on it. Examples of the base metal thin film layer include nickel, chromium, and an alloy layer thereof. When the base metal thin film layer is provided, the thickness is 1/2 or less, preferably 1/5 or less of the thickness of the copper thin film layer, and is preferably about 1 to 50 nm. This underlying metal thin film layer is also preferably formed by sputtering.

  Copper to be used may be alloy copper partially containing other metals. The copper or copper alloy formed by the sputtering method preferably has a copper content of 90% by mass or more, particularly preferably 95% by mass or more. Examples of the metal that copper can contain include chromium, zirconium, nickel, silicon, zinc, and beryllium. Moreover, the copper alloy thin film in which these metals contain 2 or more types may be sufficient.

  The thickness of the copper thin film layer formed in step d2 is preferably in the range of 0.001 to 1.0 μm, preferably 0.01 to 0.5 μm, more preferably 0.05 to 0.5 μm, and further Preferably it is 0.1-0.5 micrometer. When the copper thin film layer is further thickened, it may be thickened by electroless plating or electrolytic plating.

  According to the present invention, the adhesive force of the polyimide resin layer can be dramatically improved by a simple surface treatment. Adhesion can be improved even in low-roughness copper foils suitable for fine pitch formation, which makes it possible to manufacture copper-clad laminates used for high-density printed wiring boards at low cost, and HDD suspensions. Since it can be used for applications, its industrial value is high.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the examples of the present invention, various measurements and evaluations are as follows unless otherwise specified.

[Measurement of adhesive strength]
The measurement of adhesive strength was evaluated by measuring 180 °, 10 mm peel strength at room temperature for a sample cut into a 10 mm wide strip using a Tensilon tester (manufactured by Toyo Seiki Seisakusho). As a criterion for determining the adhesive strength, a case where the adhesive strength was 0.4 kN / m or more was accepted, and a case where it was less than 0.4 kN / m was rejected. Further, the case where the adhesive strength is 0.4 kN / m or more and less than 0.6 kN / m is good, and the case where the adhesive strength is 0.6 kN / m or more is good.

[Measurement of glass transition temperature]
Using a viscoelasticity analyzer (RSA-II, manufactured by Rheometric Science Effy Co., Ltd.), using a sample with a width of 10 mm and applying a 1 Hz vibration while raising the temperature from room temperature to 400 ° C. at a rate of 10 ° C./min. Of the loss tangent (Tan δ).

[Measurement of linear thermal expansion coefficient]
Using a thermomechanical analyzer (manufactured by Seiko Instruments Inc.), the temperature was raised to 250 ° C., held at that temperature for 10 minutes, cooled at a rate of 5 ° C./minute, and the average linear thermal expansion from 240 ° C. to 100 ° C. The coefficient (CTE) was determined.

[Measurement of modified layer thickness]
The cross section of the sample was observed using a scanning transmission electron microscope (manufactured by Hitachi High-Technologies Corporation), and the thickness of the modified layer was confirmed.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, of course, this invention is not limited to this. In addition, the symbol used in the present Example shows the following compounds.
BAPP: 2,2-bis [4- (4-aminophenoxy) phenyl] propane
HAB: 4,4 '-(3,3'-dihydroxy) diaminobiphenyl
TAPM: Tris (4-aminophenyl) methanol
DAPE: 3,4'-diaminodiphenyl ether
ASD: 4,4'-diaminobiphenyl sulfide
DABA: 4,4'-Diaminobenzanilide

In measuring the adhesive strength of a commercially available polyimide resin layer, the following two types of polyimide films were prepared.
1) Kapton EN: manufactured by Toray DuPont Co., Ltd., 100 mm × 100 mm × 25 μm thickness, coefficient of linear thermal expansion (CTE) 16 × 10 ⁻⁶ / K
2) Upilex 25S: Ube Industries, Ltd. 100 mm x 100 mm x 25 μm thickness, linear thermal expansion coefficient (CTE) 12 x 10 ^-6 / K

Reference example 1
To 425 g of N, N-dimethylacetamide, 31.8 g of 2,2′-dimethyl-4,4′-diaminobiphenyl and 4.9 g of 1,3-bis (4-aminophenoxy) benzene at room temperature for 30 minutes Stir. Thereafter, 28.6 g of pyromellitic dianhydride and 9.6 g of biphenyl-3,4,3 ′, 4′-tetracarboxylic dianhydride were added, and the solution was stirred at room temperature for 3 hours under a nitrogen atmosphere. A polyamic acid resin solution having a viscosity of 28,000 poise was obtained. This polyamic acid resin solution is applied to a stainless steel substrate, dried at 130 ° C. for 5 minutes, heated to 360 ° C. over 15 minutes to complete imidization, and a polyimide film 1 laminated on the stainless steel substrate is obtained. It was. This polyimide film 1 was peeled from the stainless steel substrate to obtain a film 1. The thermal expansion coefficient of the film 1 was 21 × 10 ⁻⁶ / K, and the thickness of the polyimide layer was 25 μm.

Reference example 2
To 200 g of N, N-dimethylacetamide, 14.9 g of 4,4′-diamino-2,2′-dimethylbiphenyl and 6.01 g of 4,4′-diaminodiphenyl ether were stirred at room temperature for 30 minutes. Thereafter, 21.4 g of pyromellitic dianhydride was added and stirred at room temperature for 3 hours under a nitrogen atmosphere to obtain a polyamic acid resin solution having a solution viscosity of 12,000 poise. This polyamic acid resin solution is applied to a stainless steel substrate, dried at 130 ° C. for 5 minutes, and heated to 360 ° C. over 15 minutes to complete imidization to form a stainless steel substrate. A laminated polyimide film 2 was obtained. The polyimide film 2 was peeled from the stainless steel substrate to obtain a film 2. The thermal linear expansion coefficient of the film 2 was 24 × 10 ⁻⁶ / K, and the thickness of the polyimide layer was 25 μm.

Reference example 3
A silane coupling agent solution was prepared by mixing 5 g of 3-aminopropyltrimethoxysilane, 500 g of methanol and 2.5 g of water and stirring for 2 hours. Stainless steel foil 1 (Shin Nippon Steel Co., Ltd. SUS304 H-TA, thickness 20 μm, surface roughness on the resin layer side: 10-point average roughness Rz 0.8 μm) washed in advance with a silane coupling agent solution (liquid temperature about 20) C.) for 30 seconds and then pulled up into the atmosphere to remove excess liquid. Then, it was dried by blowing compressed air for about 15 seconds. Thereafter, heat treatment was performed at 110 ° C. for 30 minutes to obtain a stainless steel foil 2 treated with a silane coupling agent.

Example 1
After immersing the polyimide film (Kapton EN) in a 5N potassium hydroxide aqueous solution at 50 ° C. for 5 minutes, the immersed polyimide film was sufficiently washed with ion-exchanged water, and then washed in a 1 wt% hydrochloric acid aqueous solution (25 ° C.) for 30 seconds. After soaking, the surface-treated polyimide film a1 was obtained by thoroughly washing with ion-exchanged water, spraying compressed air, and drying. The thickness of the alkali treatment layer on one side of this surface-treated polyimide film a1 was 0.70 μm. This film was immersed in a 0.0005 M concentration BAPP methanol solution (25 ° C.) for 30 seconds, and then dried by blowing compressed air to obtain a surface-treated polyimide film b1. This film was heat-treated at 300 ° C. for 3 minutes to produce a surface-treated polyimide film c1. At this time, the thickness of the modified imidized layer on one surface of the surface-treated polyimide film c1 was 0.65 μm.
Both sides of this film are sandwiched between copper foils 1 (surface roughness: Rz = 0.8 μm, thickness: 18 μm) and pressed with a high-performance high-temperature vacuum press at 370 ° C., 20 MPa for 1 minute. A copper clad laminate 1 was produced. The adhesive strength between the polyimide film and the copper foil was 1.0 kN / m. The results are shown in Table 1.

Example 2
Similar to Example 1 except that 0.0005 M concentration of BAPP methanol solution (25 ° C.) was immersed for 30 seconds in Example 1 and immersed in 0.001 M DAPE methanol solution (25 ° C.) for 5 minutes. Thus, surface-treated polyimide films a2, b2 and c2 and double-sided copper-clad laminate 2 were produced. The thickness of the modified imidized layer on one side of the surface-treated polyimide film c2 was 0.52 μm. The adhesive strength between the polyimide film and the copper foil was 0.9 kN / m. The results are shown in Table 1.

Example 3
Surface-treated polyimide films a3, b3 and c3 were prepared in the same manner as in Example 1 except that they were immersed in a 0.0005M BAPP methanol solution (25 ° C.) in Example 1 for 5 minutes instead of 30 seconds. Produced. A polyimide film c3 is sandwiched between copper foils 2 (surface roughness: Rz = 1.5 μm, thickness: 18 μm), and pressed with a high-performance high-temperature vacuum press machine at 370 ° C., 20 MPa for 1 minute, double-sided copper A tension laminate 3 was produced. The adhesive strength between the polyimide film and the copper foil was 0.6 kN / m. The results are shown in Table 1.

Example 4
Similar to Example 1 except that 0.0005M HAB methanol solution (25 ° C.) was immersed in a 0.0005M concentration BAPP methanol solution (25 ° C.) for 30 seconds instead of 0.001M HAB methanol solution (25 ° C.) in 30 minutes. Thus, surface-treated polyimide films a4, b4 and c4 and double-sided copper-clad laminate 4 were produced. The adhesive strength between the polyimide film and the copper foil was 0.7 kN / m. The results are shown in Table 1.

Example 5
Similar to Example 1 except that 0.0005 M concentration of BAPP methanol solution (25 ° C.) was immersed in 30 seconds for 30 seconds instead of 0.001 M TAPM methanol solution (25 ° C.). Thus, surface-treated polyimide films a5, b5 and c5 and double-sided copper-clad laminate 5 were produced. The adhesive strength between the polyimide film and the copper foil was 0.6 kN / m. The results are shown in Table 1.

Example 6
The polyimide film (Iupyrex 25S) was immersed in a 5N potassium hydroxide aqueous solution (50 ° C.) for 30 minutes instead of being immersed in a 5N potassium hydroxide aqueous solution at 50 ° C. for 5 minutes. In the same manner as in Example 1, surface-treated polyimide films a6, b6 and c6 and double-sided copper-clad laminate 6 were produced. The thickness of the alkali treatment layer on one side of the surface-treated polyimide film a6 was 0.56. The adhesive strength between the polyimide film and the copper foil was 1.0 kN / m. The results are shown in Table 1.

Example 7
Instead of immersing the polyimide film in a 5N aqueous potassium hydroxide solution at 50 ° C. for 5 minutes, the polyimide film (film 1 of Reference Example 1) in the 5N aqueous potassium hydroxide solution (50 ° C.) for 5 minutes. Surface-treated polyimide films a7, b7 and c7 and double-sided copper-clad laminate 7 were prepared in the same manner as in Example 1 except that the immersion was performed. The thickness of the alkali treatment layer on one side of the surface-treated polyimide film a7 was 0.22. The adhesive strength between the polyimide film and the copper foil was 1.2 kN / m. The results are shown in Table 1.

Example 8
Instead of immersing the polyimide film in a 5N aqueous potassium hydroxide solution at 50 ° C. for 5 minutes, the polyimide film (film 2 of Reference Example 2) in the 5N aqueous potassium hydroxide solution (50 ° C.) for 5 minutes. Surface-treated polyimide films a8, b8 and c8 and double-sided copper-clad laminate 8 were produced in the same manner as in Example 1 except for immersion. The thickness of the alkali treatment layer on one side of the surface-treated polyimide film a8 was 0.30. The adhesive strength between the polyimide film and the copper foil was 1.0 kN / m. The results are shown in Table 1.

Example 9
Surface-treated polyimide films a9, b9 and c9 and double-sided metal-clad laminate 9 were produced in the same manner as in Example 7 except that stainless steel foil 1 was used instead of copper foil 1. The adhesive strength between the polyimide film and the stainless steel foil was 0.9 kN / m. The results are shown in Table 1.

Example 10
Surface-treated polyimide films a10, b10 and c10 and double-sided metal-clad laminate 10 were produced in the same manner as in Example 7 except that stainless steel foil 2 was used instead of copper foil 1. The adhesive strength between the polyimide film and the stainless steel foil was 1.2 kN / m. The results are shown in Table 1.

Example 11
Surface-treated polyimide films a11, b11 and c11 and a double-sided metal-clad laminate 11 were produced in the same manner as in Example 8 except that the stainless steel foil 1 was used instead of the copper foil 1. The adhesive strength between the polyimide film and the stainless steel foil was 0.9 kN / m. The results are shown in Table 1.

Example 12
Surface-treated polyimide films a12, b12 and c12 and double-sided metal-clad laminate f12 were produced in the same manner as in Example 8 except that stainless steel foil 2 was used instead of copper foil 1. The adhesive strength between the polyimide film and the stainless steel foil was 1.0 kN / m. The results are shown in Table 1.

Example 13
After immersing a polyimide film (film 2 of Reference Example 2) in 5N potassium hydroxide aqueous solution at 50 ° C. for 30 seconds, the immersed polyimide film was sufficiently washed with ion-exchanged water, and 1 wt% hydrochloric acid aqueous solution (25 ° C. ), And then sufficiently washed with ion-exchanged water, sprayed with compressed air and dried to obtain a surface-treated polyimide film a13. The thickness of the alkali treatment layer on one surface of the surface treatment film a13 was 0.02 μm. This film was immersed in a 0.0001 M concentration BAPP methanol solution (25 ° C.) for 5 minutes, and then dried by blowing compressed air to obtain a surface-treated polyimide film b13. This film was heat-treated at 300 ° C. for 3 minutes to produce a surface-treated polyimide film c13. At this time, the thickness of the modified imidized layer on one surface of the surface-treated polyimide film c13 was about 0.02 μm.
In order to deposit a metal raw material on this film, it is set in an RF magnetron sputtering device (ANELVA; SPF-332HS), the inside of the tank is depressurized to 3 × 10 ⁻⁴ Pa, and then argon gas is introduced to reduce the degree of vacuum. Plasma was generated with an RF power source at 2 × 10 ⁻¹ Pa. With this plasma, a nickel: chromium alloy layer [ratio 8: 2, 99.9 wt%, hereinafter, a nichrome layer (first sputtering layer 13a)] was formed on a polyimide film so as to have a film thickness of 30 nm. After forming the nichrome layer, in the same atmosphere, 0.2 μm of copper (99.99 wt%) was further formed on the nichrome layer by sputtering to obtain a second sputtering layer 13b.
Next, a copper plating layer (plating layer 13c) having a thickness of 8 μm was formed in an electrolytic plating bath using the sputtered film (second sputtering layer 13b) as an electrode. As an electrolytic plating bath, a copper sulfate bath (copper sulfate 100 g / L, sulfuric acid 220 g / L, chlorine 40 mg / L, anode is phosphorus-containing copper) is used, and a plating film is formed at a current density of 2.0 A / dm ² . did. After plating, it was washed with sufficient distilled water and dried. In this manner, a metal-clad laminate e13 composed of polyimide film / nichrome layer 13a / copper sputter layer 13b / electroplated copper layer 13c was obtained. The adhesive strength between the polyimide film and copper was 0.9 kN / m. The results are shown in Table 1.

Example 14
Example 13 is the same as Example 13 except that it was immersed in a 0.001 M concentration BAPP methanol solution (25 ° C.) for 5 minutes instead of being immersed in a 0.001 M concentration HAB methanol solution (25 ° C.) for 5 minutes. Similarly, surface-treated polyimide films a14, b14 and c14 and metal-clad laminate 14 were produced. The adhesive strength between the polyimide film and copper was 0.7 kN / m. The results are shown in Table 1.

Example 15
Example 13 is the same as Example 13 except that it was immersed in a 0.0001 M concentration BAPP methanol solution (25 ° C.) for 5 minutes instead of being immersed in a 0.001 M concentration ASD methanol solution (25 ° C.) for 5 minutes. Similarly, surface-treated polyimide films a15, b15 and c215 and a metal-clad laminate 15 were produced. The adhesive strength between the polyimide film and copper was 0.6 kN / m. The results are shown in Table 1.

Example 16
Example 13 is the same as Example 13 except that it was immersed in a 0.0001 M concentration BAPP methanol solution (25 ° C.) for 5 minutes instead of being immersed in a 0.001 M concentration DABA methanol solution (25 ° C.) for 5 minutes. Similarly, surface-treated polyimide films a16, b16 and c16 and metal-clad laminate 16 were produced. The adhesive strength between the polyimide film and copper was 0.6 kN / m. The results are shown in Table 1.

Comparative Example 1
A polyimide film (Kapton EN) was sandwiched between copper foils 1 and pressed with a high-performance high-temperature vacuum press at 370 ° C., 20 MPa for 1 minute to produce a double-sided copper-clad laminate. The adhesive strength between the polyimide film and the copper foil was 0.1 kN / m. The results are shown in Table 1.

Comparative Example 2
After immersing the polyimide film (Kapton EN) in a 5N aqueous potassium hydroxide solution (50 ° C.) for 5 minutes, the immersed polyimide film was sufficiently washed with ion-exchanged water, and then added to a 1 wt% aqueous hydrochloric acid solution (25 ° C.). After being soaked in minutes, it was sufficiently washed with ion-exchanged water, dried by blowing compressed air, and a surface-treated polyimide film was produced. This film was sandwiched between copper foils 1 and pressed with a high-performance high-temperature vacuum press machine at 370 ° C., 20 MPa for 1 minute to produce a double-sided copper-clad laminate. The adhesive strength between the polyimide film and the copper foil was 0.1 kN / m. The results are shown in Table 1.

Comparative Example 3
After immersing the polyimide film (Kapton EN) in a 5N aqueous potassium hydroxide solution (50 ° C.) for 5 minutes, the immersed polyimide film was sufficiently washed with ion-exchanged water, and 5% in a 1 wt% hydrochloric acid aqueous solution (25 ° C.). After being immersed for a minute, it was sufficiently washed with ion-exchanged water and dried by blowing compressed air. The film was heat treated at 300 ° C. for 3 minutes to produce a surface-treated polyimide film. This film was sandwiched between copper foils 1 and pressed with a high-performance high-temperature vacuum press machine at 370 ° C., 20 MPa for 1 minute to produce a double-sided copper-clad laminate. The adhesive strength between the polyimide film and the copper foil was 0.1 kN / m. The results are shown in Table 1.

Comparative Example 4
After immersing the polyimide film (Kapton EN) in 0.0005M BAPP methanol solution (25 ° C) for 5 minutes, sprayed with compressed air and dried, and then heat-treated at 300 ° C for 3 minutes for surface treatment polyimide film Was made. This polyimide film was sandwiched between copper foils 1 and pressed with a high-performance high-temperature vacuum press machine at 370 ° C., 20 MPa, and 1 minute to produce a double-sided copper-clad laminate. The adhesive strength between the polyimide film and the copper foil was 0.1 kN / m. The results are shown in Table 1.

Comparative Example 5
After immersing the polyimide film (Kapton EN) in a 0.0005M BAPP methanol solution (25 ° C.) for 5 minutes, a surface-treated polyimide film was produced by blowing compressed air and drying. This polyimide film was sandwiched between copper foils 1 and pressed with a high-performance high-temperature vacuum press machine at 370 ° C., 20 MPa, and 1 minute to produce a double-sided copper-clad laminate. The adhesive strength between the polyimide film and the copper foil was 0.1 kN / m. The results are shown in Table 1.

Comparative Example 6
A polyimide film (film 2 of Reference Example 2) was prepared, set in an RF magnetron sputtering apparatus so that a metal raw material was formed on this film, the inside of the tank was depressurized to 3 × 10 ⁻⁴ Pa, and then argon Gas was introduced to make the degree of vacuum 2 × 10 ⁻¹ Pa, and plasma was generated by an RF power source. With this plasma, a nickel: chromium alloy layer [ratio 8: 2, 99.9 wt%, hereinafter, a nichrome layer (first sputtering layer 23a)] was formed on a polyimide film to a thickness of 30 nm. After forming the nichrome layer, a copper (99.99 wt%) film was further formed on the nichrome layer by sputtering in the same atmosphere to form a second sputtering layer 23b.
Subsequently, a copper plating layer (plating layer 23c) having a thickness of 8 μm was formed in an electrolytic plating bath using the sputtered film (second sputtering layer 23b) as an electrode. As an electrolytic plating bath, a copper sulfate bath (copper sulfate 100 g / L, sulfuric acid 220 g / L, chlorine 40 mg / L, anode is phosphorus-containing copper) is used, and a plating film is formed at a current density of 2.0 A / dm ² . did. After plating, it was washed with sufficient distilled water and dried. In this way, a metal-clad laminate composed of polyimide film / nichrome layer 23a / copper sputter layer 23b / electroplated copper layer 23c was obtained. The adhesive strength between the polyimide film and the copper foil was 0.1 kN / m. The results are shown in Table 1.

Comparative Example 7
After immersing the polyimide film (film 2 of Reference Example 2) in 5N potassium hydroxide aqueous solution at 50 ° C. for 30 seconds, the immersed polyimide film was sufficiently washed with ion-exchanged water, and 1 wt% hydrochloric acid aqueous solution (25 ° C. ), And then sufficiently washed with ion-exchanged water and dried by blowing compressed air.
It is set in an RF magnetron sputtering apparatus so that a metal raw material is formed on this polyimide film, the inside of the tank is depressurized to 3 × 10 ⁻⁴ Pa, argon gas is introduced, and the degree of vacuum is 2 × 10 ⁻¹ Pa. And plasma was generated by an RF power source. With this plasma, a nickel: chromium alloy layer [ratio 8: 2, 99.9 wt%, hereinafter, a nichrome layer (first sputtering layer 24a)] was formed on a polyimide film so as to have a film thickness of 30 nm. After forming the nichrome layer, copper (99.99 wt%) was further formed on the nichrome layer by sputtering in the same atmosphere to form a second sputtering layer 24b.
Subsequently, a copper plating layer (plating layer 24c) having a thickness of 8 μm was formed in an electrolytic plating bath using the sputtered film (second sputtering layer 24b) as an electrode. As an electrolytic plating bath, a copper sulfate bath (copper sulfate 100 g / L, sulfuric acid 220 g / L, chlorine 40 mg / L, anode is phosphorus-containing copper) is used, and a plating film is formed at a current density of 2.0 A / dm ² . did. After plating, it was washed with sufficient distilled water and dried. In this manner, a metal-clad laminate composed of polyimide film / nichrome layer 24a / copper sputter layer 24b / electroplated copper layer 24c was obtained. The adhesive strength between the polyimide film and the copper foil was 0.2 kN / m. The results are shown in Table 1.

Comparative Example 8
The polyimide film (film 2 of Reference Example 2) was immersed in a 0.0001M BAPP methanol solution (25 ° C.) for 5 minutes, dried by blowing compressed air, and heat-treated at 300 ° C. for 3 minutes.
A metal thin film was formed by setting in an RF magnetron sputtering apparatus so that a metal raw material was formed on this polyimide film. The inside of the tank in which the sample was set was depressurized to 3 × 10 ⁻⁴ Pa, and then argon gas was introduced to make the degree of vacuum 2 × 10 ⁻¹ Pa, and plasma was generated by an RF power source. With this plasma, a nickel: chromium alloy layer [ratio 8: 2, 99.9 wt%, hereinafter, a nichrome layer (first sputtering layer 25a)] was formed on a polyimide film to a thickness of 30 nm. After forming the nichrome layer, in the same atmosphere, 0.2 μm of copper (99.99 wt%) was further formed on the nichrome layer by sputtering to obtain a second sputtering layer 25b.
Next, a copper plating layer (plating layer 25c) having a thickness of 8 μm was formed in an electrolytic plating bath using the sputtered film (second sputtering layer 25b) as an electrode. As an electrolytic plating bath, a copper sulfate bath (copper sulfate 100 g / L, sulfuric acid 220 g / L, chlorine 40 mg / L, anode is phosphorus-containing copper) is used, and a plating film is formed at a current density of 2.0 A / dm ² . did. After plating, it was washed with sufficient distilled water and dried. In this way, a metal-clad laminate composed of polyimide film / nichrome layer 25a / copper sputter layer 25b / electroplated copper layer 25c was obtained. The adhesive strength between the polyimide film and the copper foil was less than 0.1 kN / m. The results are shown in Table 1.

  The above conditions and results are summarized in Table 1. In addition, as for the formation method of a metal layer, Examples 1-12 and Comparative Examples 1-5 are the thermocompression bonding methods, and Examples 13-16 and Comparative Examples 6-8 are a sputtering + plating method.

Claims (11)

a) a step of forming an alkali-treated layer by treating the surface of the polyimide resin layer with an aqueous alkali solution; and b) an aromatic in which two primary amino groups are substituted with aromatic rings on the surface of the alkali-treated layer. Impregnating and drying a polar solvent solution containing an aromatic amino compound composed of diamine to form an aromatic amino compound-containing layer; and c) imidizing the aromatic amino compound-containing layer to form a modified imidized layer. Forming the modified layer on the surface of the polyimide resin layer.   The method for forming a modified layer according to claim 1, wherein the thickness of the alkali treatment layer is in the range of 0.005 to 3.0 μm. The aromatic amino compound is a biphenyl ring, Ar-X-Ar, or Ar-Y-Ar-X-Ar-Y-Ar (wherein Ar is a benzene ring or a naphthalene ring which may have a substituent, X and Y are each independently a divalent group selected from CO, O, S, SO, SO ₂ , or CONH). The method for forming a modified layer according to claim 1 or 2, wherein the amino group is an aromatic diamine substituted .   The method for forming a modified layer according to any one of claims 1 to 3, wherein the polyimide resin layer is a polyimide resin layer forming a surface layer of the laminate.   The method for forming a modified layer according to any one of claims 1 to 3, wherein the polyimide resin layer is a polyimide resin layer that forms a surface layer of a polyimide resin film. a) a step of forming an alkali-treated layer by treating the surface of the polyimide resin layer with an aqueous alkali solution; and b) an aromatic in which two primary amino groups are substituted with aromatic rings on the surface of the alkali-treated layer. Impregnating and drying a polar solvent solution containing an aromatic amino compound composed of diamine to form an aromatic amino compound-containing layer; and c) imidizing the aromatic amino compound-containing layer to form a modified imidized layer. A method for producing a metal-clad laminate, comprising: a step of forming; and d) a step of forming a metal layer on the surface of the modified imidized layer.   The method for producing a metal-clad laminate according to claim 6, wherein the step of forming a metal layer on the surface of the modified imidized layer comprises the step of d1) superimposing a metal foil on the surface of the modified imidized layer and thermocompression bonding. .   The method for producing a metal-clad laminate according to claim 6, wherein the step of forming a metal layer on the surface of the modified imidized layer comprises the step of d2) forming a metal thin film layer on the surface of the modified imidized layer.   The method for producing a metal-clad laminate according to any one of claims 6 to 8, wherein the alkali-treated layer has a thickness in the range of 0.005 to 3.0 µm. The aromatic amino compound is a biphenyl ring, Ar-X-Ar, or Ar-Y-Ar-X-Ar-Y-Ar (wherein Ar is a benzene ring or a naphthalene ring which may have a substituent, X and Y are each independently a divalent group selected from CO, O, S, SO, SO ₂ , or CONH). The method for producing a metal-clad laminate according to any one of claims 6 to 9, which is an aromatic diamine substituted with an amino group .   The method for producing a metal-clad laminate according to claim 7, wherein the metal foil is a copper foil, a copper alloy foil, or a stainless steel foil.