JP5180517B2 - Surface treatment method for polyimide resin and method for producing metal-clad laminate - Google Patents

Description

  The present invention relates to a method for surface modification of a polyimide resin and a method for producing a metal-clad laminate in which a metal layer is laminated on a surface-modified polyimide resin layer. More specifically, the present invention relates to a polyimide resin layer surface treatment method suitable for a printed wiring board and a metal-clad laminate manufacturing method.

  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 made by forming and 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, the printed wiring board is flexible and flexible. Broadly divided into flexible printed wiring boards. The flexible printed wiring board is a necessary part for connection in a movable part that is constantly bent. 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 the flexible substrate that is a material of the flexible printed wiring board, polyimide ester or polyimide resin is often used as the insulating resin, 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 base film layer (main layer of an insulating resin layer), an adhesive layer, and a laminated board composed of a copper foil layer, and a base film layer and a copper foil layer without using an adhesive. There is a laminate composed of two layers. 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 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 increase the fine pitch. In order to make a printed wiring board fine pitch, 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.

  The base film layer is desirably a polyimide resin layer having a low thermal expansion coefficient in order to prevent curling, but there is a conflicting relationship between low thermal expansion and adhesiveness. In order to improve the adhesive strength, various surface modification techniques for polyimide films have been reported. One example is a surface modification method by plasma treatment. For example, JP-A-5-222219 (Patent Document 1), JP-A-8-12779 (Patent Document 2), JP-A-11-209488 (Patent Document 3), JP-A-2004-51712 (Patent Document). Specific examples are disclosed in Document 4) and Japanese Patent Application Laid-Open No. 2006-7518 (Patent Document 5). 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 using wet etching, which is advantageous in terms of cost, is attracting attention. However, in general, the adhesion improvement effect is not sufficient compared to a surface modification method using dry etching such as plasma treatment. There was a need for further improvements. As such a surface modification method by wet etching, for example, Japanese Patent Application Laid-Open No. 11-49880 (Patent Document 6) can be cited. According to Patent Document 6, 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 metal-clad laminate having an extremely thin adhesive layer, and a method for producing a metal-clad laminate having sufficient adhesive strength to meet the fine pitch of printed circuit boards. With the goal.

  In order to achieve the above object, the present inventors have studied, and when the surface of the polyimide resin layer is modified by a specific treatment, the thickness of the polyimide resin layer is hardly changed, and adhesion to the metal foil is performed. The inventors have found that an improved polyimide resin layer having high strength can be obtained, and have completed the present invention.

That is, according to the present invention, the polyimide resin layer on the surface side is represented by the following formula (1).
H ₂ N—CH ₂ —A—CH ₂ —NH ₂ (1)
(Here, A represents a divalent organic group having a benzene ring and composed only of carbon atoms and hydrogen atoms , and the number of carbon atoms contained in A is 2 to 18.)
A contact treatment step in which a surface contact treatment layer is formed by contact treatment with an organic treatment agent having two amino groups represented by the functional group, and the surface contact treatment layer is heated to form a modified imidized layer. A surface treatment method for a polyimide resin layer, comprising a modified imidized layer forming step to be formed. Here, the said heat processing is performed at 300-420 degreeC.

  In the above manufacturing method, if a plasma treatment step is performed before the contact treatment step to form a plasma treatment layer surface by plasma treatment, the modification effect is improved.

  The present invention also includes a metal-clad laminate comprising a crimping step in which a metal foil is superimposed on the surface of a polyimide resin layer having a modified imidized layer obtained by any of the above methods and thermocompression bonded. It is a manufacturing method of a body.

  Here, the metal foil is one of copper foil, copper alloy, or stainless steel foil, or the metal foil and the modified imidized layer are thermocompression bonded via the silane coupling agent treatment layer. Doing gives a better metal-clad laminate.

  Furthermore, in the present invention, a copper thin film layer is formed by vapor-depositing copper directly or via a base metal thin film layer on the surface of a polyimide resin layer having a modified imidized layer obtained by any of the above methods. A method for producing a metal-clad laminate, comprising the step of forming a copper thin film.

  Hereinafter, the surface treatment method of the polyimide resin layer according to the present invention will be described, and then the method for producing the metal-clad laminate according to the present invention will be described. The “polyimide resin layer” in the present invention has a meaning including both “a layer made of a polyimide resin film” and “a polyimide resin layer of a laminate having a polyimide resin layer”. Therefore, the polyimide resin layer may be a polyimide resin layer of a laminate or a polyimide resin film.

  The polyimide resin layer used in the present invention is not particularly limited, and may be a film (or sheet) made of polyimide resin, in a state of being laminated on a substrate such as a copper foil, a glass plate, or a resin film. It may be a polyimide resin layer. However, at least one surface of the polyimide resin layer exists as a surface layer. When both of the surface layers are polyimide resin layers, one or both surfaces can be treated. The surface-treated polyimide resin layer obtained in the present invention has at least two layers of an initial polyimide resin layer (unmodified polyimide resin layer) and a modified imidized layer as polyimide resin layers. In addition, in the case of the polyimide resin layer laminated | stacked on the base material, a base material means materials, such as a resin sheet or metal foil with which a polyimide resin layer is laminated | stacked.

  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 resin 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 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, the present invention can also be applied to a polyimide resin layer that exceeds the thermal linear expansion coefficient.

As a polyimide resin which comprises a polyimide resin layer, the polyimide resin which has a structural unit represented by General formula (2) is preferable. In General Formula (2), Ar ₁ represents a tetravalent aromatic group represented by Formula (3) or Formula (4), and Ar ₃ represents a divalent 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, and X and Y independently represent a single bond or a divalent hydrocarbon having 1 to 15 carbon atoms. A divalent group selected from the group, O, S, CO, SO ₂ or CONH, and n independently represents an integer of 0 to 4; q represents the molar ratio of the constituent units, and is in the range of 0.1 to 1.0, preferably 0.5 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 (2), 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 these combinations.

  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.

  Others, 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 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] 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'-diaminodiphenylsulfone, 3,3'-diaminodiph Nylsulfone, 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 '-[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-diamino Examples thereof include pyridine, 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.

  Others, 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- Or 3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3- or 3,4-dicarboxyphenyl) ethane dianhydride, 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-di Carboxyphenyl) tetrafluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic Acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6 -Tet Carboxylic 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, pyrazine-2,3, 5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4-bis Mention may also be made of (2,3-dicarboxyphenoxy) diphenylmethane dianhydride.

  Each of the diamine and acid anhydride may be used alone or in combination of two or more. In addition, diamines and acid anhydrides other than those mentioned above can be used in combination. In this case, the proportion of diamines or acid anhydrides other than those mentioned above is 90 mol% or less, preferably 50 mol% or less. Controlling 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 of 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 resin solution of the polyamic acid on the substrate is not particularly limited, and it can be applied with a coater such as a comma, die, knife, lip or the like.

  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 as a laminate, or may be used as a film after being peeled off.

  The polyimide resin layer may be a single layer or 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. A monolayer having the simplest layer structure can be advantageously obtained industrially. The polyimide resin layer has a thickness of 3 to 100 μm, preferably 3 to 50 μm.

  The surface treatment method for a polyimide resin layer of the present invention includes a contact treatment step and a modified imidized layer formation step.

  In the contact treatment step, the surface layer of the polyimide resin layer is modified with an organic treatment agent having at least two amino groups represented by the above formula (1) as functional groups (hereinafter also referred to as amino compounds). A quality treatment layer is formed. In said formula (1), A shows a bivalent organic group, and the number of the carbon atoms contained in A is 2-18, Preferably it is 2-11, More preferably, it is 4-10. A may be a divalent organic group composed of only carbon atoms and hydrogen atoms, or may be a divalent organic group containing a nitrogen atom, an oxygen atom, a sulfur atom or a silicon atom. The organic treating agent used in the present invention has at least two amino groups bonded to the terminal methylene group. A compound having an amino group bonded to carbon forming a cyclo ring or an aromatic ring, but not having at least two amino groups bonded to a terminal methylene group does not have the effect of the present invention or is few.

  When A is a divalent organic group composed of only a carbon atom and a hydrogen atom, the divalent organic group is preferably an alkylene group or a phenylene group containing a linear, branched or cyclo ring. Specific examples of such amino compounds having a divalent organic group include, for example, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 2-methyl-1,5-diamino. Pentane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1,9-diaminononane, 1,10-diaminodecane Examples include diaminoalkanes such as 1,11-diaminoundecane and 1,12-diaminododecane, and xylylenediamines such as metaxylylenediamine and paraxylylenediamine.

  When A is a divalent organic group containing a nitrogen atom, an oxygen atom, a sulfur atom or a silicon atom, a specific example of the amino compound having such a divalent organic group is tris (2-amino Ethyl) amine, N, N′-bis (2-aminoethyl) -1,3-propanediamine, bis (3-aminopropyl) ethylenediamine, 1,4-bis (3-aminopropyl) piperazine, diethylenetriamine, N— Amines containing nitrogen atoms such as methyl-2,2′-diaminodiethylamine, 3,3′-diaminodipropylamine, N, N-bis (3-aminopropyl) methylamine, bis (3-aminopropyl) Ether, 1,2-bis (2-aminoethoxy) ethane, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxaspiro [5.5] -unde Amines containing oxygen atoms such as amines, amines having sulfur atoms such as 2,2′-thiobis (ethylamine), and silicon atoms such as 1,3-bis (3-aminopropyl) tetramethyldisiloxane There are amines.

  Among the amino compounds represented by the above formula (1), A is a divalent hydrocarbon group composed of only a carbon atom and a hydrogen atom, or a divalent organic group containing a nitrogen atom, an oxygen atom or a sulfur atom. It is preferable that Among these divalent groups, a divalent hydrocarbon group, a divalent organic group containing a nitrogen atom, a divalent organic group containing an oxygen atom, and then a divalent organic group containing a sulfur atom Are preferred in this order. Among divalent hydrocarbon groups, a divalent organic group containing a benzene ring is good, and an amino compound containing a benzene ring tends to obtain an effect of improving the adhesive strength with the metal foil.

  Said amino compound may be used independently and can also be used in combination of 2 or more type. Moreover, other amino compounds other than the amino compound represented by the above formula (1) can be used in combination. In this case, the other amino compound is 90 mol% or less, preferably 50 mol% or less, more preferably It is good to set it as 20 mol% or less.

  The organic processing agent is preferably liquid or solid at normal temperature, and the boiling point thereof is preferably 100 ° C. or higher, more preferably 150 ° C. or higher. However, at a temperature of 300 to 400 ° C. or higher, it is preferable to have a vapor pressure or to decompose and evaporate. If it is a solid, it must be dissolved in a solvent.

  The organic treatment agent can be used as it is as long as it is liquid at room temperature around 10 to 40 ° C. However, the organic treatment agent tends to become non-uniform in thickness, or the organic treatment agent is modified. Since the amount deposited on the layer tends to increase, it is preferably used as a solution diluted with a solvent. The solvent is not particularly limited as long as it can be mixed or dissolved with an organic processing agent, but it is advantageous to use a polar solvent. Examples of the polar solvent include 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 N-methylpyrrolidone, N, N-dimethyl. Tertiary amines such as acetamide and dimethylformamide, dimethyl sulfoxide and the like can be mentioned, and N-methylpyrrolidone and N, N-dimethylacetamide are preferable. These can be used alone or in combination of two or more, and some aromatic hydrocarbons such as xylene and toluene can also be used. The boiling point of the solvent should be lower than that of the organic processing agent, and preferably 200 ° C. or lower.

  The concentration of the solution containing the organic treating agent is 0.0001 to 5M (0.0001 to 5 mol / L), preferably 0.001 to 2M, more preferably 0.01 to 1M. Is appropriate.

  The method of treating with the organic treating agent is not particularly limited as long as the organic treating agent or the solution of the organic treating agent can contact the layer on the surface side of the polyimide resin layer, and a known method can be used. Although it is possible to make it contact uniformly. For example, a dipping method, a spray method, a brush coating method or a printing method can be used. The temperature may be 0-100 ° C, preferably 10-40 ° C. Advantageously, the solution of the organic treating agent is applied to a constant thickness of about 10 to 100 μm.

  A contact treatment step of forming a surface contact treatment layer by bringing an organic treatment agent or an organic treatment agent solution into contact with the surface layer side of the polyimide resin layer is performed. In this contact treatment step, an organic treatment agent or an organic treatment agent solution is impregnated inside the surface layer of the polyimide resin layer to form a surface contact treatment layer. The thickness of the surface contact treatment layer can be adjusted by the contact time and temperature, but is preferably about 1/100 to 1/10 of the polyimide resin layer thickness, and is preferably in the range of 0.1 to 5 μm from another viewpoint. .

  Next, this surface contact treatment layer is heat-treated. The heat treatment is performed by causing at least a partial reaction between the organic treating agent and the polyimide resin to form an amide group, and maintaining the temperature at which the amide group is imidized for a predetermined time. When performing a contact treatment process using the solution of an organic processing agent, it is preferable to dry this before the heat treatment process.

  The conditions of the heat treatment for generating the amide group are 1 to 60 minutes at a temperature of 100 to 200 ° C, preferably 2 to 20 minutes at 120 to 180 ° C. The conditions for the heat treatment for imidization are 1 to 300 minutes at a temperature of 130 to 420 ° C., preferably 3 to 30 minutes at 180 to 380 ° C. In the heat treatment, a batch method in which the temperature is raised stepwise or a continuous curing method in which the temperature is continuously raised may be used, and the method is not limited. The heat treatment for generating an amide group and the heat treatment for imidization may be performed continuously or simultaneously.

  At a temperature of 100 to 200 ° C., it is considered that an amide reaction in which an amino group of the organic treating agent undergoes a nucleophilic substitution reaction with an imide group present in the polyimide resin layer (particularly on the surface) to generate an amide group. In that case, drying and a part of excess organic processing agent may evaporate in parallel. Furthermore, at a temperature of 130 ° C. or higher, an imidization reaction in which part of the amide group becomes an imide group may occur in parallel. This imidation reaction is usually completed at 300 to 420 ° C. In addition, if there exists an unreacted organic processing agent, a part will participate in an amide reaction and imidation reaction, and a part will evaporate. Therefore, it is thought that the adhesiveness of the polyimide resin layer is improved as a result of the surface treatment of the polyimide resin being amidated by this heat treatment to lower the molecular weight and then imidizing it.

  When imidizing, either imidization by heating or chemical imidization using a catalyst as described above is possible, and it is not limited. However, when imidation by heating is insufficient, it depends on the catalyst. Chemical imidization may be used in combination.

  In the polyimide resin layer surface treatment method of the present invention, a plasma treatment step may be provided before the modification treatment step. By forming the plasma treatment layer surface by this plasma treatment, the surface side layer of the polyimide resin layer can be roughened or the chemical structure of the surface side layer can be changed. This is considered to improve the wettability of the surface-side layer and increase the affinity with the organic treatment agent. Examples of the organic treatment agent in which this plasma treatment is particularly advantageous include amino compounds (for example, metaxylylenediamine, paraxylylenediamine, etc.) that show a solid state at a room temperature of 10 to 40 ° C., and include a plasma treatment step. Thus, the modified imidized layer surface can be formed uniformly.

  As the plasma, for example, an atmospheric pressure type plasma processing apparatus is used, and plasma of argon, helium, nitrogen, or a mixed gas thereof is generated in a vacuum processing chamber. In this case, the processing pressure is preferably in the range of 5,000 to 200,000 Pa, the processing temperature is in the range of 10 to 40 ° C., and the high frequency (or microwave) output is preferably in the range of 50 to 400 W.

  The method for producing a metal-clad laminate of the present invention is prepared by preparing a polyimide resin layer having a modified imidized layer surface-treated by any of the above methods, on the modified imidized layer on the surface of the polyimide resin layer. A crimping step of superimposing metal foils and thermocompression bonding is provided.

  The method for thermocompression bonding is not particularly limited, and a known method can be adopted as appropriate. 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 used.

  As the metal foil, copper foil, copper alloy foil or stainless steel foil is suitable. 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 (including a copper alloy foil containing copper as a main component) 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 a copper foil with small surface roughness in the manufacturing method of this invention, it 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.

  The metal foil may be subjected to a silane coupling agent treatment on the surface in contact with the modified imidized layer. 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, at least one selected from 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane is 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.

  The laminate obtained by the method for producing a metal-clad laminate of the present invention is a laminate having a metal foil on one side or both sides of a polyimide resin layer. A laminate having a metal foil on one side is obtained by laminating a metal foil on the surface of a modified imidized layer obtained by the surface treatment method for a polyimide resin layer of the present invention. When the surface-treated polyimide resin layer is laminated on a substrate such as glass or a resin film, the substrate is preferably peeled before or after the metal foil is laminated. When the substrate is a metal foil such as a copper foil, a double-sided metal-clad laminate can be obtained by laminating a metal foil on the polyimide resin layer side. Moreover, after forming a modified imidation layer on both surfaces of a polyimide film other than said method, the metal-clad laminated body which has metal foil on both surfaces is obtained by laminating | stacking metal foil on this both surfaces. Further, after producing a single-sided metal-clad laminate having a metal foil on one side, the modified imidized layer is formed on the surface side of the polyimide resin layer of at least one single-sided metal-clad laminate, It can also be produced by a method in which a single-sided metal-clad laminate of polyimide layers is laminated and thermocompression bonded.

  A second method for producing a metal-clad laminate of the present invention is to prepare a polyimide resin layer having a modified imidized layer treated by the surface treatment method, and directly or on the surface of the modified imidized layer. A copper thin film forming step of forming a copper thin film layer by evaporating copper through the layer is provided.

  The copper thin film layer is formed by vapor-depositing copper. At this time, a base metal thin film layer for improving the adhesiveness is provided on the modified imidized layer, and a copper thin film layer is provided thereon. Good. 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 vapor deposition.

As a vapor deposition method for forming the copper thin film layer, a known method can be employed. 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. Regarding the conditions for forming the copper 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 .

  Copper to be used may be alloy copper partially containing other metals. The copper or copper alloy formed by vapor deposition 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 the copper thin film forming step 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. More preferably, the thickness is 0.1 to 0.5 μm. 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, although an Example demonstrates this invention further in detail, this invention is not limited to this. In the following examples, various evaluations are based on the following unless otherwise specified.

[Measurement of adhesive strength]
The adhesive strength was measured by cutting the obtained metal-clad laminate into a 1 mm wide strip using a press, 90 ° at room temperature, and 1 mm peel strength using a Tensilon tester (manufactured by Toyo Seiki Seisakusho). It was measured.

[Measurement of linear thermal expansion coefficient]
The linear thermal expansion coefficient was measured using a thermomechanical analyzer (manufactured by Seiko Instruments Inc.) at a rate of 20 ° C./min up to 255 ° C., held at that temperature for 10 minutes, and then further 5 ° C./min. It was cooled at a constant speed. The average coefficient of thermal expansion from 240 ° C. to 100 ° C. during cooling was calculated and used as the linear thermal expansion coefficient.

  Next, based on an Example, this invention is demonstrated concretely. Of course, the present invention is not limited to this.

Production Example 1
In a 500 mL separable flask, 20.7 g of 4,4′-diamino-2′-methoxybenzanilide (0.08 mol) was dissolved in 343 g of N, N-dimethylacetamide with stirring. Next, 28.5 g of pyromellitic anhydride (0.13 mol) and 10.3 g of 4,4′-diaminodiphenyl ether (0.05 mol) were added to the solution in a nitrogen stream. Thereafter, stirring was continued for about 3 hours to conduct a polymerization reaction, and a viscous polyamic acid solution A was obtained. The obtained polyamic acid solution A was applied onto a substrate, dried at 130 ° C. for 5 minutes, then heated to 360 ° C. over 15 minutes to complete imidization, and the substrate was removed to obtain polyimide film A Got. It was 23 * 10 < ^-6 > / K when the thermal linear expansion coefficient of the obtained polyimide film A was measured. The polyimide film A had a thickness of 10 μm.

Production Example 2
The polyimide film A obtained in Production Example 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 the applied pressure is 3 under normal pressure. A plasma of 2 kV and an output of 200 W was input for plasma discharge, and the polyimide layer A was subjected to plasma treatment for 30 seconds to obtain a polyimide film B.

Production 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. Then, heat processing were performed for 30 minutes at 110 degreeC, and the stainless steel foil 3 of silane coupling agent processing was obtained.

Production Example 4
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. Copper foil 1 (thickness 18 μm, resin layer surface roughness: 10-point average roughness Rz 0.8 μm) previously washed with water was immersed in a silane coupling agent solution (liquid temperature about 20 ° C.) for 30 seconds, and then once in the atmosphere Raised to, dropped 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 copper foil 4 of the silane coupling agent process was obtained.

  A solution of an organic treating agent was prepared by dissolving 1.36 g of metaxylylenediamine (10 mmol) in 10 mL of N, N-dimethylacetamide. This solution was applied to the polyimide film B obtained in Preparation Example 2 to a thickness of 50 μm, heated at 130 ° C. for 2 minutes, heated to 160 ° C. and dried, and then heated to 360 ° C. over 15 minutes. The imidization was completed by heating to obtain a polyimide film having a modified imidized layer. Stainless steel foil 1 was superimposed on the surface of the modified imidized layer of the obtained polyimide film, and pressed with a high-performance high-temperature vacuum press at 370 ° C., 20 MPa for 1 minute to produce a metal-clad laminate. . The adhesive strength between the polyimide film and the stainless steel foil was 0.6 kN / m.

  A metal-clad laminate was produced in the same manner as in Example 1 except that the stainless steel foil 3 obtained in Production Example 3 was used instead of the stainless steel foil 1. The adhesive strength between the polyimide film and the stainless steel foil was 0.9 kN / m.

  In place of the stainless steel foil 1, except that the copper foil 2 (Mitsui Metals NS-VLP foil, copper foil thickness 9 μm, resin layer surface roughness: 0.8 μm) was used, the same as in Example 1, A metal-clad laminate was produced. The adhesive strength between the polyimide film and the copper foil was 0.9 kN / m.

  A metal-clad laminate was produced in the same manner as in Example 1 except that the copper foil 4 obtained in Production Example 4 was used instead of the stainless steel foil 1. The adhesive strength between the polyimide film and the copper foil was 1.1 kN / m.

  A polyimide film having a modified imidized layer was obtained in the same manner as in Example 1 except that 1.36 g (10 mmol) of paraxylylenediamine was used instead of 1.36 g (10 mmol) of metaxylylenediamine. Subsequently, a metal-clad laminate was produced. The adhesive strength was 0.6 kN / m.

  Except for using 1.36 g (10 mmol) of paraxylylenediamine instead of 1.36 g (10 mmol) of metaxylylenediamine, and using the stainless steel foil 3 obtained in Preparation Example 3 instead of the stainless steel foil 1 Obtained a polyimide film having a modified imidized layer in the same manner as in Example 1, and then produced a metal-clad laminate. The adhesive strength was 0.8 kN / m.

  Instead of 1.36 g (10 mmol) of metaxylylenediamine, 1.46 g (10 mmol) of tris (2-aminoethyl) amine is used, and polyimide film A obtained in Preparation Example 1 is used instead of polyimide film B. A polyimide film having a modified imidized layer was obtained in the same manner as in Example 1 except that a metal-clad laminate was produced. The adhesive strength was 0.5 kN / m.

  A polyimide having a modified imidized layer in the same manner as in Example 1 except that 1.46 g (10 mmol) of tris (2-aminoethyl) amine was used instead of 1.36 g (10 mmol) of metaxylylenediamine. A film was obtained, and then a metal-clad laminate was produced. The adhesive strength was 0.5 kN / m.

  Instead of 1.36 g (10 mmol) of metaxylylenediamine, 1.46 g (10 mmol) of tris (2-aminoethyl) amine was used, and the stainless steel foil 3 obtained in Preparation Example 3 was used instead of the stainless steel foil 1. A polyimide film having a modified imidized layer was obtained in the same manner as in Example 1 except that a metal-clad laminate was produced. The adhesive strength was 0.6 kN / m.

  Instead of 1.36 g (10 mmol) of metaxylylenediamine, 1.46 g (10 mmol) of tris (2-aminoethyl) amine was used, and instead of polyimide film B, polyimide film A obtained in Preparation Example 1 was used. A polyimide film having a modified imidized layer was obtained in the same manner as in Example 1 except that the stainless steel foil 3 was used instead of the stainless steel foil 1, and then a metal-clad laminate was produced. . The adhesive strength was 0.6 kN / m.

  Instead of 1.36 g (10 mmol) of metaxylylenediamine, 1.46 g (10 mmol) of bis (3-aminopropyl) ethylenediamine was used, and instead of polyimide film B, the polyimide film A obtained in Preparation Example 1 was used. A polyimide film having a modified imidized layer was obtained in the same manner as in Example 1 except that the stainless steel foil 3 was used instead of the stainless steel foil 1, and then a metal-clad laminate was produced. . The adhesive strength was 0.6 kN / m.

  1.48 g (10 mmol) of 1,3-bis (3-aminopropyl) tetramethylsiloxane was used in place of 1.36 g (10 mmol) of metaxylylenediamine, and obtained in Preparation Example 1 instead of polyimide film B. The polyimide film A was used, and a polyimide film having a modified imidized layer was obtained in the same manner as in Example 1 except that the stainless steel foil 3 was used instead of the stainless steel foil 1. A stretched laminate was produced. The adhesive strength was 0.5 kN / m.

  Instead of 1.36 g (10 mmol) of metaxylylenediamine, 2.00 g (10 mmol) of 1,4-bis (3-aminopropyl) piperazine was used and obtained in Preparation Example 1 instead of polyimide film B. A polyimide film having a modified imidized layer was obtained in the same manner as in Example 1 except that the polyimide film A was used, and the stainless steel foil 3 was used instead of the stainless steel foil 1, and then a metal-clad laminate was obtained. The body was made. The adhesive strength was 0.4 kN / m.

A solution of an organic processing agent in which 1.36 g of metaxylylenediamine (10 mmol) was dissolved in 10 mL of N, N-dimethylacetamide was prepared, and this processing solution was applied on the polyimide film B obtained in Preparation Example 2 to a thickness of 50 μm. A polyimide having a modified imidized layer, heated at 130 ° C. for 2 minutes, heated to 160 ° C. and dried, then heated to 360 ° C. over 15 minutes to complete imidization A film was obtained. The copper thin film layer was formed by setting in an RF magnetron sputtering apparatus so that the copper raw material was formed on the surface of the modified imidized layer of the polyimide film having the obtained modified imidized layer. After the pressure inside the tank in which the polyimide film was set was reduced to 3 × 10 ⁻⁴ Pa, 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 or a first sputtering layer) was formed on a polyimide film so as to have a film thickness of 30 nm. After forming the nichrome layer, a second sputtering layer was formed by further sputtering 0.2 μm of copper (99.99 wt%) on the nichrome layer by sputtering in the same atmosphere.

Subsequently, a copper plating layer having a thickness of 8 μm was formed in an electrolytic plating bath using the copper sputtered film (second sputtering layer) 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 / copper sputter layer / electroplated copper layer was produced. The adhesive force between the polyimide film and copper was 0.6 kN / m.

Comparative Example 1
A stainless steel foil 1 was superposed on the surface of the polyimide film A produced in Production Example 1 and was pressed with a high-performance high-temperature vacuum press machine at 370 ° C., 20 MPa for 1 minute to produce a metal-clad laminate. The adhesive strength between the polyimide film and the stainless steel foil was less than 0.1 kN / m.

Comparative Example 2
A stainless steel foil 1 was superposed on the surface of the polyimide film B produced in Production Example 2, and was pressed with a high-performance high-temperature vacuum press machine at 370 ° C., 20 MPa for 1 minute to produce a metal-clad laminate. The adhesive strength between the polyimide film and the stainless steel foil was less than 0.1 kN / m.

Comparative Example 3
A copper foil 2 was placed on the surface of the polyimide film A produced in Production Example 1 and pressed with a high-performance high-temperature vacuum press machine at 370 ° C., 20 MPa for 1 minute to produce a metal-clad laminate. The adhesive strength between the polyimide film and the copper foil was less than 0.1 kN / m.

Comparative Example 4
The copper foil 4 obtained in Preparation Example 4 is superimposed on the surface of the polyimide film A prepared in Preparation Example 1, and is pressed with a high-performance high-temperature vacuum press machine at 370 ° C., 20 MPa, for 1 minute. A laminate was produced. The adhesive strength was less than 0.1 kN / m.

Comparative Example 5
A surface-treated polyimide film (in the same manner as in Example 1, except that 2.10 g (10 mmol) of 4,4′-methylenebiscyclohexylamine was used instead of 1.36 g (10 mmol) of metaxylylenediamine (10 mmol). Corresponding to a polyimide film having a modified imidized layer, the same in the following comparative examples) was obtained, and then a metal-clad laminate was produced. The adhesive strength between the polyimide film and the stainless steel foil was 0.2 kN / m.

Comparative Example 6
Surface treatment was carried out in the same manner as in Example 1 except that 1.12 g (10 mmol) of 1,4-diazabicyclo [2.2.2] octane was used instead of 1.36 g (10 mmol) of metaxylylenediamine. A polyimide film was obtained, and then a metal-clad laminate was prepared. The adhesive strength between the polyimide film and the stainless steel foil was 0.2 kN / m.

Comparative Example 7
In the same manner as in Example 1 except that 1.52 g (10 mmol) of 1,8-diazabicyclo [5.4.0] undecene-7 was used instead of 1.36 g (10 mmol) of metaxylylenediamine, the surface A treated polyimide film was obtained, and then a metal-clad laminate was produced. The adhesive strength between the polyimide film and the stainless steel foil was 0.1 kN / m.

Comparative Example 8
A solution of an organic processing agent in which 1.61 g of ethanolamine (10 mmol) was dissolved in 10 mL of N, N-dimethylacetamide was prepared, and this processing solution was formed on the polyimide film A obtained in Preparation Example 1 to a thickness of 50 μm. After heating at 130 ° C. for 2 minutes, heating to 160 ° C. and drying, the temperature was raised to 360 ° C. over 15 minutes to obtain a surface-treated polyimide film. Stainless steel foil 1 was superimposed on the treated surface of the obtained surface-treated polyimide film, and pressed with a high-performance high-temperature vacuum press machine at 370 ° C., 20 MPa, for 1 minute to produce a metal-clad laminate. The adhesive strength between the polyimide film and the stainless steel foil was less than 0.1 kN / m.

Comparative Example 9
A copper thin film layer was formed by setting in an RF magnetron sputtering apparatus so that a copper raw material was formed on the surface of the polyimide film A obtained in Production Example 1. The inside of the tank in which the polyimide film A 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. A nickel: chromium alloy layer (ratio 8: 2, 99.9 wt%, nichrome layer, first sputtering layer) was formed on the polyimide film by this plasma so as to have a film thickness of 30 nm. After forming the nichrome layer, a second sputtering layer was formed by further sputtering 0.2 μm of copper (99.99 wt%) on the nichrome layer by sputtering in the same atmosphere.

Subsequently, a copper plating layer having a thickness of 8 μm was formed in an electrolytic plating bath using the copper sputtered film (second sputtering layer) 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 / copper sputter layer / electroplated copper layer was produced. The adhesive force between the polyimide film and copper was less than 0.1 kN / m.

The above results are summarized in Table 1. In addition, the symbol in a table | surface shows the following compound.
MXDA: Metaxylylenediamine
PXDA: paraxylylenediamine
TAEA: Tris (2-aminoethyl) amine
BAPEA: Bis (3-aminopropyl) ethylenediamine
BAPTS: 1,3-bis (3-aminopropyl) tetramethylsiloxane
BAPPy: 1,4-bis (3-aminopropyl) piperazine
MBCHA: 4,4'-methylenebiscyclohexylamine
DABCO: 1,4-diazabicyclo [2.2.2] octane
DBU: 1,8-diazabicyclo [5.4.0] undecene-7
EA: Ethanolamine

Claims (7)

The surface layer side of the polyimide resin layer is represented by the following formula (1)
H ₂ N—CH ₂ —A—CH ₂ —NH ₂ (1)
(In the formula, A has a benzene ring, represents a divalent organic group composed of only carbon atoms and hydrogen atoms , and A contains 2 to 18 carbon atoms)
A contact treatment step in which a surface contact treatment layer is formed by contact treatment with an organic treatment agent having two amino groups represented by the functional group, and the surface contact treatment layer is heated at 300 to 420 ° C. A surface treatment method for a polyimide resin layer, comprising a modified imidized layer forming step for forming a quality imidized layer.
  The surface treatment method for a polyimide resin layer according to claim 1, wherein the polyimide resin layer is a polyimide resin layer or a polyimide resin layer of a laminate having a polyimide resin layer.   The surface of the polyimide resin layer according to claim 1 or 2, wherein a plasma treatment step of forming a plasma treatment layer surface by plasma treatment of the surface side layer of the polyimide resin layer is provided before the contact treatment step. Processing method.   A pressure-bonding step in which a metal foil is superimposed on the surface of the polyimide resin layer on which a modified imidized layer obtained by surface treatment by the surface treatment method for a polyimide resin layer according to any one of claims 1 to 3 is formed and thermocompression bonded. A method for producing a metal-clad laminate, comprising:   5. The method for producing a metal-clad laminate according to claim 4, wherein the metal foil is a copper foil, a copper alloy, or a stainless steel foil.   The method for producing a metal-clad laminate according to claim 4 or 5, wherein the surface of the polyimide resin layer on which the metal foil and the modified imidization are formed is thermocompression bonded through a silane coupling agent treatment layer.   Copper is applied directly or via a base metal thin film layer to the surface of the polyimide resin layer on which the modified imidized layer obtained by surface treatment by the surface treatment method for a polyimide resin layer according to any one of claims 1 to 3 is formed. A method for producing a metal-clad laminate comprising a copper thin film forming step of forming a copper thin film layer by vapor deposition.