JPWO2008018399A1 - Method for modifying surface of polyimide resin layer and method for producing metal-clad laminate - Google Patents

Abstract

The present invention relates to a surface treatment method for dramatically improving the adhesion of a polyimide resin layer by a simple surface treatment. According to this surface treatment method, since the adhesive force can be improved even in a low-roughness copper foil suitable for fine pitch formation, a metal-clad laminate used for high-density printed wiring boards and HDD suspension boards can be obtained. Obtainable. The surface treatment includes a) a step of plasma-treating a surface layer of the polyimide resin layer to form a plasma-treated layer surface, and b) drying and heat treatment after applying a polar solvent solution containing an amino compound to the plasma-treated layer surface. And forming a surface modification layer. The polyimide resin layer having a modified layer on the surface obtained by this surface treatment is suitable for obtaining a metal-clad laminate for a wiring board by forming a metal layer on this surface by thermocompression bonding or vapor deposition.

Description

  The present invention relates to a surface modification 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 particularly, a surface modification for a polyimide resin layer suitable for a printed wiring board. The present invention relates to a method and 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. Depending on the type of insulating resin used as the base material, a plate-shaped rigid printed wiring is used. 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 plate composed of two layers of a base film layer and a copper foil layer 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. In addition, a flexible substrate having a copper foil layer on both sides is also known, and after manufacturing a single-sided flexible substrate having a copper foil layer on one side, a method of laminating two single-sided flexible substrates on each other or a single-sided flexible substrate A method of laminating copper 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 has been an increasing demand for higher performance and higher functionality in electronic devices, and accordingly, higher density of printed wiring plates, 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. 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, surface modification by plasma treatment is an advantageous technique not only in terms of productivity, stability and cost, but also in terms of environmental conservation. 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, these conventional techniques cannot obtain a satisfactory adhesive force between the copper foil having a low surface roughness and the polyimide resin layer.

  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. This discloses 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. 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.

  In order to achieve the above-mentioned object, the present inventors have studied, and by appropriately combining surface modification by plasma treatment and a wet surface treatment method, the polyimide resin layer using this has the thickness of the polyimide resin layer. It was found that an excellent copper-clad laminate having high adhesive strength with the copper foil can be provided without substantially changing the thickness.

  The present invention includes: a) a step of plasma-treating a surface layer of a polyimide resin layer to form a plasma-treated layer surface; and b) applying a polar solvent solution containing an amino compound to the plasma-treated layer surface, followed by drying and heat treatment. And forming a modified layer on the surface of the polyimide resin layer.

  The present invention also provides a metal-clad laminate comprising: I) a step I for forming a modified layer on the surface of the polyimide resin layer; and II) a step II for forming a metal layer on the surface of the modified layer. In the method, Step I includes a) a step of plasma-treating a surface layer of the polyimide resin layer to form a plasma-treated layer surface, and b) drying after applying a polar solvent solution containing an amino compound to the plasma-treated layer surface. And a step of forming a surface-modified layer by heat treatment, and a method for producing a metal-clad laminate.

  Examples of the amino compound include aromatic amines or aliphatic amines, preferably aromatic amines or aliphatic amines having a primary or secondary amino group. Aromatic amines include amino-substituted nitrogen-containing heterocyclic compounds.

  Step I) includes d) a step of superimposing a metal foil on the surface modification layer of the polyimide resin layer and thermocompression bonding, or e) a step of forming a metal thin film layer by vapor deposition on the surface modification layer of the polyimide resin layer. It should be chosen.

  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. The polyimide resin layer has at least two layers of an initial polyimide resin layer (unmodified polyimide resin layer) and a modified layer by being surface-modified. The modified layer is formed on the surface of the polyimide resin layer and is formed by a treatment including an operation of coating an amino compound solution, and is also referred to as a coat layer or an amino compound coat layer.

  The polyimide resin that forms the polyimide resin layer refers to a heat-resistant resin having an imide group in the structure such as polyamideimide, polybenzimidazole, polyimide ester, polyetherimide, polysiloxaneimide, including so-called polyimide resin. A commercially available polyimide resin or polyimide film can also be used.

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 coefficient of thermal expansion is 1 × 10 ⁻⁶ to 30 × 10 ⁻⁶ (1 / K), preferably 1 × 10 ^{−6 to} 25 × 10 ⁻⁶ (1 / K), and 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(2)又は式(3)で表される4価の芳香族基を示し、Ar₃は式(4)又は式(5)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 (2) or formula (3), and Ar ₃ represents a divalent aromatic group represented by formula (4) or formula (5). 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 , CO, SO, SO ₂ or CONH represents a divalent group, n independently represents an integer of 0 to 4, q represents an abundance ratio of structural 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 dianhydride, a specific example of the polyimide resin can be understood by explaining the diamine and the acid dianhydride. 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.

  Further, 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'-diaminodiphenylpropane, 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'- Aminobiphenyl, 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-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 , 5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine and the like.

  Examples of the acid dianhydride include pyromellitic anhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride 4,4′-oxydiphthalic anhydride is preferred.

  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.

  In addition, 1,2,7,8-, 1,2,6,7- or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6,7-anthracene tetracarboxylic acid Anhydride, 2,2-bis (3,4-dicarboxyphenyl) tetrafluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 2,3,6,7-naphthalene tetracarboxylic acid Anhydride, 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 dianhydride, 2 , 3,6,7- (or 1,4,5,8-) tetrachloronaphthalene-1,4,5,8- (or 2,3,6,7-) tetracarboxylic dianhydride, 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-Tetracarboxylic dianhydride, Razine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride 4,4-bis (2,3-dicarboxyphenoxy) diphenylmethane dianhydride and the like.

Each of diamine and acid dianhydride may be used alone or in combination of two or more. Similarly, the general formula (1) does not give the Ar ₃ or Ar ₁ when using other diamine or dianhydride, other diamine or diacid proportion each total diamine or total diacid anhydrides 90 mol% or less of the anhydride, preferably 50 mol% or less, more preferably 20 mol% or less. By selecting the type of diamine and acid dianhydride, or the molar ratios when using two or more diamines or acid dianhydrides, thermal expansion, adhesion, glass transition point (Tg), etc. Can be controlled.

  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. The method is suitable. 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 heat treatment 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, more preferably 5 to 30 μm.

  In the method of forming a modified layer (coat layer) on the surface of the polyimide resin layer of the present invention, a) a step of forming a plasma treatment layer surface by plasma treatment of the surface side of the polyimide resin layer (step a); b) A step of applying a polar solvent solution containing an amino compound to the surface of the plasma treatment layer, drying and heat treatment to form a surface modified layer (step b).

In step a, a known method such as glow discharge is employed as the plasma treatment method. The plasma treatment conditions can be arbitrarily selected. When the amino compound used in step b is an aromatic amine, the discharge output is preferably ²⁰ to 10,000 W · min / m ² , more preferably. Is preferably 1500 to 8000 W · min / m ² , more preferably 3000 to 6000 W · min / m ² . Further, the amino compound used in step b is an aliphatic amine, the discharge output is preferably 300~30000W · min / m ^2, more preferably 2000~20000W · min / m ^2, more preferably 5000 to 18000W · min / m ² is good. In any case, the pressure is preferably 1 Torr or less. By performing plasma treatment under such conditions, cleavage of the imide ring of the surface layer resin of the polyimide resin layer occurs, and a modified plasma treatment layer surface is formed. It is considered that a functional group having high reactivity such as a carboxyl group is generated by cleavage of the imide ring or the like on the treated layer surface, and this improves the coupling effect with the amino group of the amino compound used in step b.

  The atmospheric gas in the plasma treatment is preferably a gas selected from oxygen, argon, helium, nitrogen, and a mixed gas thereof, and particularly preferably oxygen, argon, helium, or a mixed gas thereof.

  In step b, a polar solvent solution containing an amino compound (referred to as an amino compound solution) is applied to the surface of the plasma treatment layer, dried and heat-treated to form an amino compound coat layer. Preferred examples of the amino compound include aromatic amines and aliphatic amines. Here, coating means forming a film of an amino compound solution.

The aromatic amine 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. And it is preferable not to have a silicon element in a molecule | numerator. The number of amino groups is 1-5, preferably 1-3, more preferably 1 or 2. The molecular weight of the aromatic amine is 40 to 1000, preferably 50 to 600, and more preferably 60 to 500. An aromatic amine is a compound having at least one amino group in at least one aromatic ring, and the aromatic ring may or may not be substituted with a substituent other than an amino group. 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 an alkyl group having 1 to 18 carbon atoms (for example, methyl, ethyl, propyl, etc.), an aromatic group having 6 to 13 carbon atoms (for example, phenyl), and 7 to 12 carbon atoms. An arylalkyl group (for example, benzyl) etc. are mentioned. 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 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 amine is shown next, it is not limited to this. One or more aromatic amines 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'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl Sulfone, 3,3'-diaminodiphenylsulfone, 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-phenylene Diamine, 2,6-diaminopyridine, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4 '-[1,4-phenylenebis (1- Methyl ethylidene)] bi Aniline, 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, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine, 5-amino-1H-tetrazole, 2-amino-1,3,5- Triazine-4,6-dithiol, 3-amino-1,2,4-triazine, 3-amino-1,2,4-triazole, 4-amino-1,2,4-triazole, 3-amino-1, 2,4-triazole-5-carboxylic acid, 3-amino-1,2,4-triazole-5-thiol, 2-amino-5-trifluoromethyl-1,3,4-thiadiazole, 5-aminoindazole, 4-aminoindole, 5-aminoindole, 3-amino-1H-isoindole, 1-aminoisoquinoline, 5-aminoisoquinoline, 3-aminoisoxazole, 5-amino-2-mercaptobenzimidazole, 6-amino- 2-mercaptobenzothiazole, 4-amino-6-mercaptopyrazolo [3,4-d] pyrimidine, 2-amino-4-methoxybenzothiazole, 3-amino -5-phenylpyrazole, 3-amino-1-phenyl-2-pyrazolin-5-one, 2-amino-4-phenyl-5-tetradecylthiazole, 2-amino-5-phenyl-1,3,4- Thiadiazole, 2-amino-4-phenylthiazole, 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol, 3-aminophthalhydrazine, 2-amino-6- (methylsulfonyl) benzo Thiazole, 2-amino-4-methylthiazole, 2-amino-5- (methylthio) -1,3,4-thiadiazole, 3-amino-5-methylthio-1H-1,2,4thiazole, 6-amino- 1-methyluracil, 3-amino-5-nitrobenzisothiazole, 9-amino-1,2,3,4-tetrahydroacridine, 9-aminoacridine, 2-amino-1,3,4-thiadiazole, 5- Amino-1,3,4-thiadiazole-2-thiol, 2-aminothiazole, 2-amino-4-thiazole acetic acid, 2-amino-2-thiazolyl 2-amino-6-thiocyanate benzothiazole, DL-α-amino-2-thiophene acetic acid, 3-amino-5-hydroxypyrazole, 2-amino-3-hydroxypyridine, 5-amino-8-hydroxyquinoline 2-amino-4-hydroxy-6-trifluoromethylpyrimidine, 2-aminoimidazole, 5-aminoimidazole-4-carboxamide, 4-amino-5-imidazolecarboxamide, 2-amino-4,5-imidazole Dicarbonitrile, 4-amino-6-hydroxy-2-mercaptopyrimidine, 2-amino-4-hydroxy-6-methylpyrimidine, 2-amino-6-purinethiol, aminopyrazine, 3-aminopyrazine-2-carboxylic acid Acid, 3-aminopyrazole, 3-amino-4-pyrazolecarbonitrile, 3-amino-4-pyrazolecarboxamide, 3-amino-4-pyrazolecarboxylic acid, 4-aminopyrazolo [3,4 d] pyrimidine.

1-aminopyrene, 2-aminopyridine, 3-aminopyridine, 4-aminopyridine, 4-amino-5- (4-pyridyl) -4H-1,2,4-triazole-3-thiol, 2-aminopyrimidine, 4-aminopyrimidine, N ⁴ - (2-amino-4-pyrimidinyl) sulfanilamide, 3-aminopyrrolidine, 4-amino Kinari Jin, 3-aminoquinoline, 3-Aminorodanin, 1- (3-aminopropyl) imidazole, 2-aminopurine, adenine, 4- (aminomethyl) piperidine, 3- (aminomethyl) piperidine, 2- (aminomethyl) piperidine, 3-amino-5-methylpyrazole, 2- (aminomethyl) pyridine, 3- (Aminomethyl) pyridine, 4- (aminomethyl) pyridine, 2-amino-4-methylpyrimidine, 3-amino-2-methyl-4 (3H) quinazolinone, 5-amino-2-methylindole, 5-amino- 3-methylisothiazole, 3-a No-5-methylisoxazole, 3-amino-2-methoxydibenzofuran, 2-amino-α- (methoxyimino) -4-thiazole acetic acid, 2-amino-4-methoxy-6-methylpyrimidine, 2 -Amino-4-methoxy-6-methyl-1,3,5-triazine, 3-amino-5- (4-methoxyphenyl) pyrazole, 5-amino-2-methoxypyridine, 4-amino-6-methoxypyrimidine 8-amino-6-methoxyquinoline, 2- (aminomethyl) benzimidazole, 2-amino-1-methylbenzimidazole, azaadenine, thioguanine. These can be mentioned as aromatic amines.

  Among the above aromatic amines, amino group-substituted nitrogen-containing heterocyclic compounds are preferable, or aromatic amino compounds substituted with hydroxyl groups or mercapto groups, or nitrogen-containing heterocyclic compounds substituted with hydroxyl groups or mercapto groups are preferable. Such an aromatic amine has, for example, a nitrogen atom constituting a heterocyclic ring, or an oxygen atom or sulfur atom constituting a substituent, thereby strengthening a chemical bond with a metal layer formed in a later step. It is considered possible. As specific examples, preferably 2-amino-1,3,5-triazine-4,6-dithiol, 4,5-diamino-2,6-dimercaptopyrimidine, 5-amino-1,3,4-thiazole -2-thiol. In the case where the step e is provided, the use of such an aromatic amine is particularly effective when a copper thin film layer is directly formed without providing a base metal layer such as a nichrome layer.

  The aliphatic amine is preferably an aliphatic amine having a primary or secondary amino group. In particular, a compound having a primary amino group is preferable. And it is preferable not to have a silicon element in a molecule | numerator. The number of amino groups is 1-5, preferably 1-3, more preferably 1 or 2. The aliphatic amine should have a molecular weight of 10 to 1000, preferably 20 to 500, more preferably 30 to 300. The aliphatic amine may or may not be substituted with a substituent other than an amino group. When the number of amino groups present in one molecule of an aliphatic amine is 1, substituents other than amino groups are preferably those having, for example, a hydroxyl group or a mercapto group, which are formed in a later step. It is considered that the chemical bond with the metal layer can be strengthened. Specific examples include ethanolamine and 2-aminoethanethiol.

  Although the specific example of an aliphatic amine is shown next, these can use 1 or more types.

  Ethylenediamine, ethanolamine, 2-aminoethanethiol, N-methylethylenediamine, N-ethylethylenediamine, N-methylethanolamine, asym-dimethylethylenediamine, 1-amino-3,3-diethoxypropane, trans-4-aminocyclo Hexanol, D-2-amino-1-butanol, L-2-amino-1-butanol, 4-amino-1-butanol, 4-amino-2-butanol, (R)-(-)-2-aminobutane, (S)-(+)-2-aminobutane, 1-amino-2-propanol, 3-amino-2-propanol, 2-amino-1,3-propanediol, 3-amino-1,2-propanediol, DL-2-amino-3-methyl-1-butanol, 6-amino-2-methyl-2-heptanol, methylamine, ethylamine, dimethylamine, diethylamine, diethylenetriamine and the like can be mentioned.

  The amino compound is used as a solution in a polar solvent. The polar solvent is not particularly limited as long as it dissolves an amino compound. For example, alcohols such as water, methanol, ethanol, propanol and butanol, ketones such as acetone, dimethyl ketone and methyl ethyl ketone, ethers such as tetrahydrofuran, tertiary amines such as N-methylpyrrolidone, dimethylacetamide and dimethylformamide, Or dimethyl sulfoxide etc. are mentioned, These 1 type (s) or 2 or more types can be used together and used.

  The concentration of the polar solvent solution containing the amino compound is 0.0001 to 1M (0.0001 to 1 mol / L), preferably 0.0001 to 0.1M as the concentration of the amino compound. Is appropriate.

  The coating method is not particularly limited as long as it can be brought into contact with a solution of a polar solvent containing an amino compound on the surface of the plasma 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. When applying the dipping method, it is effective that the impregnation time is 30 seconds to 5 hours, preferably 1 minute to 3 hours.

  After application, it is dried and heat-treated. Drying is performed to remove the polar solvent. The heat treatment is performed in order that at least a part of the amino compound reacts with a carboxy group generated by the plasma treatment and a part of the imide bond of the polyimide resin is decomposed to bond with the polyimide resin through an amide bond or an imide bond.

  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.

  After drying or during drying, the coating layer is formed by raising the temperature to a predetermined temperature and performing heat treatment. This heat treatment is considered necessary for the amidation reaction or imidation reaction between the terminal carboxyl group generated by cleavage of the imide ring of the polyimide resin and the amino group of the amino compound. The reaction is considered to occur in the order of an amidation reaction and an imidation reaction. And at least one part of an amino compound should advance to imidation reaction. This heat treatment can be performed simultaneously with the drying when the imidization reaction can be caused under the conditions of the drying method. When heat treatment is performed after drying, the heating temperature is preferably 50 to 400 ° C., preferably 80 to 400 ° C. If the heat treatment is insufficient, chemical treatment with a catalyst may be used in combination. .

  After the heat treatment is performed to form the modified layer (amino compound coat layer), it is preferable to include a step of removing the amino compound adhering to the surface of the resin layer. Such a step can also be performed in the above heat treatment step, and can be applied to an amino compound having a boiling point equal to or lower than the heating temperature applied when the heat treatment is performed. Amino compounds can be volatilized off. It is advantageous to provide a cleaning step of dissolving and removing an amino compound that has excessively adhered to the resin layer surface with an organic solvent.

  As the organic solvent used in this washing step, a solvent capable of dissolving an amino compound can be used. Solvents for dissolving amino compounds include hydrocarbon alcohols having 1 to 8 carbon atoms such as methanol, ethanol, propanol, isopropanol, butanol, tert-butanol, pentanol, hexanol, heptanol, octanol, etc. -6 hydrocarbon ketones such as acetone, propanone, methyl ethyl ketone, pentanone, hexanone, methyl isobutyl ketone, cyclohexanone, etc., hydrocarbon ethers having 4 to 12 carbon atoms such as diethyl ether, ethylene glycol dimethyl ether, diethylene glycol C3-C7 hydrocarbon esters such as dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, tetrahydrofuran, etc., for example, methyl acetate Ethyl acetate, propyl acetate, butyl acetate, γ-butyrolactone, diethyl malonate and the like amides having 3 to 6 carbon atoms such as dimethylformamide, dimethylacetamide, tetramethylurea, hexamethylphosphoric triamide, sulfoxide having 2 carbon atoms Compounds such as dimethyl sulfoxide and other halogen-containing compounds having 1 to 6 carbon atoms such as chloromethane, bromomethane, dichloromethane, chloroform, carbon tetrachloride, dichloroethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane C 4-8 hydrocarbon compounds such as chlorobenzene, o-dichlorobenzene, for example, butane, hexane, heptane, octane, benzene, toluene, xylene and the like can be used. From an economical viewpoint, inexpensive methanol is preferably used.

The method for washing the resin layer surface with an organic solvent in the washing step is not limited. It may be immersed in a solvent, or may be sprayed off with a spray or the like, or may be wiped off by being soaked in a suitable base material. In this cleaning, the amino compound excessively attached to the surface is dissolved and removed, but the amino compound may be left on the surface of the polyimide resin layer so that the amino compound film has a thickness of about a monomolecular film. The temperature of the solvent in the washing step at this time is preferably in the range of 0 to 100 ° C, more preferably 5 to 50 ° C. The cleaning time is preferably in the range of 1 to 1000 seconds, more preferably 3 to 600 seconds. The amount of the solvent used is preferably in the range of 1 to 500 L, more preferably 3 to 50 L per 1 m ² of the polyimide resin layer. After washing, drying is performed to obtain a polyimide resin layer having a modified layer on the surface.

  The modified layer finally obtained is considered to be composed of a polyimide resin layer containing an amino compound reacted with a carboxyl group of the polyimide resin, and a partially unreacted amino compound adhered to the surface or impregnated inside. In the polyimide resin layer having the modified layer obtained by the method of the present invention on the surface, the thickness of the modified layer is preferably substantially the same as the thickness of the plasma treatment layer. More preferably, it is about 1/1000000 to 1/10 of the thickness of the polyimide resin layer, more preferably about 1/600000 to 1/100. The thickness can be adjusted by selecting the plasma treatment time, the type of amino compound, and the solution concentration. It is advantageous to have a thickness of 0.0005 to 0.3 μm, more preferably 0.0006 to 0.1 μm.

  Next, the details of the method for producing the metal-clad laminate of the present invention will be described. The method for producing a metal-clad laminate includes a step I of forming a modified layer on the surface of a polyimide resin layer and a step II of providing a metal layer on the modified layer formed in step I.

  The step I of forming the modified layer on the surface of the polyimide resin layer includes the step a and the step b. Step a and step b in step I can be performed in the same manner as the method for forming the modified layer on the surface of the polyimide resin layer. The surface-treated polyimide resin layer obtained by this method is subjected to Step II. Since the polyimide resin layer having the modified layer obtained in the step I on the surface is modified in surface and has excellent adhesiveness, it increases the adhesive force with the metal layer.

  Step II is a step of providing a metal layer on the modified layer formed in Step I. As a method of providing the metal layer, there are a method of superimposing a metal foil on the surface of the modified layer and thermocompression bonding (step d), or a method of forming a metal thin film layer by vapor deposition (step e).

  Examples of the metal constituting the metal layer include iron, nickel, beryllium, aluminum, zinc, indium, silver, gold, tin, zirconium, stainless steel, tantalum, titanium, copper, lead, magnesium, manganese, and alloy foils thereof. . Among these, copper, copper alloy, or stainless steel is suitable. The thickness of the metal layer is 0.001 to 50 μm, preferably 0.1 to 30 μm.

  In step d, the method for thermocompression bonding 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 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. The stainless steel foil is not limited in material, but for example, a stainless steel foil such as 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 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. In particular, for copper foils used in applications where fine pitch is required, the surface roughness is suitably 10-point average roughness of 0.1 to 1.0 μm.

  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.

  Next, in step II, a method for producing a metal-clad laminate including step e will be described. Steps a and b are carried out as described above, and then subjected to step e.

In the step e, the method for forming the metal thin film layer by vapor deposition is not particularly limited. For example, a vacuum vapor deposition method, a sputtering method, an electron beam vapor deposition method, an ion plating method and 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 formation conditions of the metal thin film layer by the sputtering method, for example, argon gas is used as a 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 e 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.

  The laminate obtained by the method for producing a metal-clad laminate of the present invention is a laminate having a metal layer such as a copper foil on one side or both sides of a polyimide resin layer. A laminate having a metal layer on one side can be obtained by forming a metal layer on the modified layer of the polyimide resin layer. When the polyimide resin layer is laminated on a substrate such as glass or resin film, a modified layer is formed on the polyimide resin layer side, and a metal thin film layer is formed on the layer to form a metal-clad laminate. After that, it is peeled off if necessary. When a polyimide resin layer is laminated on a metal foil such as a copper foil, a modified layer is formed on the polyimide resin layer side, and a metal layer is formed thereon to form a double-sided metal-clad laminate. it can. In addition to the above method, in the case of a laminate having a metal layer on both sides, when a modified layer is formed on both sides of the polyimide resin layer, the metal layer is formed on both sides by thermocompression bonding or vapor deposition. Is obtained. Further, 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.

  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 following examples, various measurements and evaluations are as follows unless otherwise specified.

Adhesive strength The adhesive strength was measured by measuring 180 °, 10 mm peel strength at room temperature for a sample cut into a 10 mm width 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, a case where the adhesive strength is 0.4 kN / m or more and less than 0.5 kN / m is suitable, and a case where the adhesive strength is 0.5 kN / m or more is good.

Linear thermal expansion coefficient The linear thermal expansion coefficient was measured using a thermomechanical analyzer (manufactured by Seiko Instruments Inc.), heated to 250 ° C, held at that temperature for 10 minutes, and then cooled at a rate of 5 ° C / minute. The average coefficient of linear thermal expansion (CTE) from 240 ° C. to 100 ° C. was determined.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to this.

Production 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 was 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 laminated on the stainless steel substrate was obtained. . This polyimide film was peeled from the stainless steel substrate to obtain polyimide film F-1. The thermal expansion coefficient of this film F-1 was 21 × 10 ⁻⁶ / K, and the thickness of the polyimide layer was 25 μm.

Production Example 2
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. Then, heat processing were performed for 30 minutes at 110 degreeC, and the stainless steel foil 2 of a silane coupling agent process was obtained.

Example 1
The polyimide film F-1 is put into a vacuum plasma processing apparatus (Plasma Cleaner VE-1500II, Mori Engineering Co., Ltd.), and in an oxygen atmosphere, power is output at 1000 W to perform plasma discharge, and plasma treatment is performed for 30 seconds. A polyimide film F-2 having a plasma treatment layer was obtained. The surface of the plasma treatment layer of this film was immersed in an amino compound solution (bath temperature 20 ° C.) in which 160 mg of 2-amino-1,3,5-triazine-4,6-dithiol was dissolved in 1 L of methanol for 160 minutes. And once pulled up into the air, the excess liquid was dropped. Then, it was dried by blowing compressed air for about 15 seconds. Then, the modified layer was formed by heat-processing at 300 degreeC for 3 minute (s). Furthermore, in order to wash away an excess amino compound adhering to the film surface, the film is washed by immersing in 750 mL of methanol (bath temperature about 20 ° C.) for 60 seconds, and then immersed in 750 mL of ion-exchanged water (bath temperature of about 20 ° C.) for 60 seconds. Then, compressed air was blown for about 15 seconds and dried to obtain a polyimide film F-3 having a modified layer.

A copper thin film layer was formed by setting in an RF magnetron sputtering apparatus so that copper was formed on the modified layer surface of the obtained film F-3. The inside of the tank in which the laminate 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, copper (99.99 wt%) was formed to a thickness of 0.2 μm to obtain a first sputtering layer 1a. Next, a copper plating layer (plating layer 1b) having a thickness of 8 μm was formed in an electrolytic plating bath using the copper sputtered film (first sputtering layer 1a) 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, and the anode is phosphorous copper) is used to form a plating film 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 resin layer / copper sputter layer 1a / electroplated copper layer 1b was obtained. The adhesive strength between the polyimide resin layer and the metal layer was 0.8 kN / m.

Example 2
A polyimide film F-4 having a modified layer in the same manner as in Example 1 except that the amount of 2-amino-1,3,5-triazine-4,6-dithiol used in the amino compound solution was 80 mg. Got. Using this polyimide film F-4, a metal-clad laminate composed of a polyimide resin layer / copper sputter layer / electroplated copper layer was produced in the same manner as in Example 1. The adhesive strength between the polyimide resin layer and the metal layer was 0.8 kN / m.

Example 3
A solution obtained by dissolving 160 mg of 2-amino-1,3,5-triazine-4,6-dithiol in 1 L of methanol (bath temperature 20 ° C.) was applied to the plasma-treated surface of the polyimide film F-2 having the plasma-treated layer of Example 1. ) For 30 seconds, surface treatment was carried out, and once it was pulled up in the air, the excess liquid was dropped. Then, it was dried by blowing compressed air for about 15 seconds. Then, the polyimide film F-5 which has a modified layer was obtained by heat-processing at 130 degreeC for 10 minute (s). Using this polyimide film F-5, a metal-clad laminate composed of polyimide resin layer / copper sputter layer / electrolytically plated copper layer was produced in the same manner as in Example 1. The adhesive strength between the polyimide resin layer and the metal layer was 0.5 kN / m.

Example 4
The surface of the polyimide film F-2 having a plasma processing layer was treated with a solution (bath temperature 20 ° C.) of 160 mg of 2-amino-1,3,5-triazine-4,6-dithiol dissolved in 1 L of methanol for 30 minutes. The surface treatment was performed by dipping, and it was once pulled up in the air, and excess liquid was dropped. Then, it was dried by blowing compressed air for about 15 seconds. Then, the polyimide film F-6 which has a modified layer was obtained by heat-processing at 300 degreeC for 3 minute (s). Thereafter, it is composed of a polyimide resin layer / a copper sputtered layer / an electroplated copper layer in the same manner as in Example 1 except that the cleaning process for removing excess amino compound adhering to the surface of the coat layer was not performed. A metal-clad laminate was produced. The adhesive strength between the polyimide resin layer and the metal layer was 0.5 kN / m.

Example 5
As in Example 1, except that 174 mg of 4,5-diamino-2,6-dimercaptopyrimidine was used in place of 2-amino-1,3,5-triazine-4,6-dithiol in the amino compound solution. Thus, a polyimide film F-7 having a modified layer was obtained. Using this polyimide film F-7, a metal-clad laminate composed of polyimide resin layer / copper sputter layer / electroplated copper layer was produced in the same manner as in Example 1. The adhesive strength between the polyimide resin layer and the metal layer was 0.6 kN / m.

Example 6
Example 1 except that in the amino compound solution, 150 mg of 5-amino-1,3,4-thiazole-2-thiol was used instead of 2-amino-1,3,5-triazine-4,6-dithiol In the same manner as described above, a polyimide film F-8 having a modified layer was obtained. Using this polyimide film F-8, a metal-clad laminate composed of polyimide resin layer / copper sputter layer / electroplated copper layer was produced in the same manner as in Example 1. The adhesive strength between the polyimide resin layer and the metal layer was 0.7 kN / m.

Comparative Example 1
A metal-clad laminate was produced in the same manner as in Example 1 except that the treatment with the amino compound solution was not performed in Example 1. The adhesive strength between the polyimide resin layer and the metal layer was 0.3 kN / m.

Comparative Example 2
A metal-clad laminate was prepared in the same manner as in Example 1 except that the plasma treatment and the treatment with an amino compound solution in Example 1 were not performed. The adhesive strength between the polyimide resin layer and the metal layer was 0.3 kN / m.

Example 7
The polyimide film F-1 is passed through a room in which a mixed gas of argon gas 7 L / min, helium gas 3 L / min and nitrogen gas 0.3 L / min is injected, and under normal pressure, the applied pressure is 3.2 kV and the output is 200 W. The plasma was discharged by inputting the electric power, and the surface layer (both sides) of the film was subjected to plasma treatment for 5 minutes to obtain a polyimide film F-9 having a plasma treatment layer. The plasma-treated surface of this film was surface-treated by immersing it in a solution (bath temperature 20 ° C.) in which an organic surface treatment agent in which 60 mg of ethylenediamine was dissolved in 1 L of methanol was dissolved for 5 minutes. The liquid was dropped. Then, it was dried by blowing compressed air for about 15 seconds. Then, the modified layer was formed by heat-processing at 300 degreeC for 3 minute (s). Further, in order to wash off excess ethylenediamine adhering to the surface, the polyimide resin layer is immersed in 750 mL of methanol (bath temperature of about 20 ° C.) for 60 seconds, and then washed with 750 mL of ion-exchanged water (bath temperature of about 20 ° C.). It was immersed for 60 seconds, and then compressed air was sprayed for about 15 seconds and dried to obtain a polyimide film F-10 having a modified layer.

  The obtained film F-10 was sandwiched between two pieces of copper foil 1 (surface roughness: Rz = 0.8 μm, thickness: 18 μm), and it was 370 ° C., 20 MPa, 1 minute with a high-performance high-temperature vacuum press. The pressing was performed under the conditions of the above to obtain a double-sided metal-clad laminate. The adhesive strength between the polyimide resin layer and the metal layer was 0.4 kN / m.

Example 8
A polyimide film F-11 having a modified layer was obtained in the same manner as in Example 7 except that a solution obtained by dissolving 61 mg of ethanolamine in 1 L of methanol was used as the amino compound solution. A double-sided metal-clad laminate was prepared in the same manner as Example 7 using the polyimide film F-11. The adhesive strength between the polyimide resin layer and the metal layer was 0.4 kN / m.

Example 9
A double-sided metal-clad laminate was obtained in the same manner as in Example 7 except that the stainless steel foil 1 was used instead of the copper foil 1. The adhesive strength between the polyimide resin layer and the metal layer was 0.4 kN / m.

Example 10
A double-sided metal-clad laminate was obtained in the same manner as in Example 7 except that the stainless steel foil 2 was used instead of the copper foil 1. The adhesive strength between the polyimide resin layer and the metal layer was 0.5 kN / m.

Comparative Example 3
A double-sided copper-clad laminate was prepared in the same manner as in Example 7 except that the plasma treatment and the treatment with the amino compound solution in Example 7 were not performed and the untreated polyimide film F-1 was used. The adhesive strength between the polyimide resin layer and the metal layer was 0.01 kN / m.

Comparative Example 4
A double-sided copper clad laminate was produced in the same manner as in Example 7 except that the treatment with the amino compound solution in Example 7 was not performed and the polyimide film F-9 having a plasma treatment layer was used. The adhesive strength between the polyimide resin layer and the metal layer was 0.02 kN / m.

Industrial applicability

  According to the present invention, the adhesive force of the polyimide resin layer can be dramatically improved by a simple surface treatment. Since the adhesive force can be improved even in a low-roughness copper foil suitable for fine pitch formation, a copper-clad laminate used for a high-density printed wiring board can be manufactured at low cost. Further, since it can also be used for HDD suspension applications, its industrial value is high.

Claims (9)

  a) Plasma treatment of the surface of the polyimide resin layer to form a plasma treatment layer surface; b) Surface modification by applying a polar solvent solution containing an amino compound to the plasma treatment layer surface, followed by drying and heat treatment Forming the modified layer on the surface of the polyimide resin layer.   The method according to claim 1, wherein the amino compound is an aromatic amine or an aliphatic amine.   The method according to claim 1, wherein the amino compound is an aromatic amine or an aliphatic amine having a primary or secondary amino group.   The method according to claim 3, wherein the aromatic amine is an amino group-substituted nitrogen-containing heterocyclic compound. In the method for producing a metal-clad laminate comprising the step I of forming a modified layer on the surface of the polyimide resin layer and the step II of forming a metal layer on the surface of the modified layer,
Process I is
a) Plasma treatment of the surface of the polyimide resin layer to form a plasma treatment layer surface; b) Surface modification by applying a polar solvent solution containing an amino compound to the plasma treatment layer surface, followed by drying and heat treatment A method for producing a metal-clad laminate, comprising: forming a layer. Step II is
The method for producing a metal-clad laminate according to claim 5, comprising d) superposing a metal foil on the surface modification layer of the polyimide resin layer and thermocompression bonding. Step II is
The method for producing a metal-clad laminate according to claim 5, comprising a step of e) forming a metal thin film layer by vapor deposition on the surface modification layer of the polyimide resin layer.   The method for producing a metal-clad laminate according to claim 5, wherein the amino compound is an aromatic amine or an aliphatic amine having a primary or secondary amino group.   The method for producing a metal-clad laminate according to claim 8, wherein the aromatic amine is an amino group-substituted nitrogen-containing heterocyclic compound.