JP2006088410A - Manufacturing method of polyimide/metal foil laminated sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-resistant polyimide/metal foil laminated sheet improved in the adhesiveness between polyimide and a metal foil in order to realize the fine wiring and multilayered lamination of a flexible printed wiring board at a low cost. <P>SOLUTION: After a silane coupling agent and/or a siloxane oligomer is applied to one side or both sides of a polyimide film and, after the coated polyimide film is dried, a thermoplastic polyimide precursor varnish is applied to one side or both sides of the polyimide film to manufacture an adhesive polyimide film. The metal foil is bonded to one side or both sides of the adhesive polyimide film under heating and pressure. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a polyimide metal foil laminate widely used for flexible printed wiring boards and the like.

  In recent years, with the downsizing and portability of electronic devices, there is an increasing demand for highly heat-resistant polyimide metal foil laminates capable of high-density mounting of components and elements as circuit board materials. There are various performances required for polyimide metal foil laminates, such as heat resistance and dimensional stability. With the recent trend toward fine wiring and multilayer lamination of flexible printed wiring boards (FPC), The improvement of the peeling strength (peel strength) between resin (polyimide) is especially requested | required. As fine wiring progresses, the peel strength appears to have dropped, so the metal wiring part can be easily peeled off from the polyimide due to thermal history during circuit processing, chemical treatment, peeling of the cover material and resist, etc. is expected. On the other hand, as multilayer lamination progresses, high temperature and high pressure processes for lamination and chemical treatment in circuit processing processes are required, so the stress on the polyimide metal foil laminate also increases. It is expected that the peel strength will decrease.

  From the above, with respect to polyimide metal foil laminates, improvement of peel strength has been conventionally studied as one of the important issues. For example, in Japanese Patent Laid-Open No. 5-222219 (Patent Document 1), the surface wettability is improved by plasma treatment on the polyimide film surface, and the adhesion between the polyimide film, the adhesive, and the metal foil is improved. Is being considered. However, this method has a problem that a large plasma processing apparatus is required and the manufacturing cost becomes high.

  Therefore, in Japanese Patent Application Laid-Open No. 2001-233973 (Patent Document 2) and Japanese Patent Application Laid-Open No. 6-100714 (Patent Document 3), the surface of the polyimide film is intentionally roughened by polishing with a liquid abrasive to wett the surface. There is disclosed a method of intentionally producing unevenness on the surface by improving polyimide or depositing polyimide fine particles mixed at the time of forming a polyimide film on the polyimide surface, thereby improving surface wettability. However, in these methods, the surface is basically roughened by several μm, and if the polyimide layer is further thinned in the future, the contribution of the roughened portion of the surface will increase with respect to the overall ratio, and the partial Breaking due to a decrease in rigidity and deterioration of dielectric loss due to pinhole formation are expected and not preferable.

As another method, in order to improve the adhesion of the polyimide film surface, Japanese Patent Application Laid-Open No. 11-48423 (Patent Document 4) describes the surface of the non-thermoplastic polyimide film and the thermoplastic polyimide film as a silane coupling agent, After surface modification with siloxane oligomers, it has been studied to improve adhesion by laminating both films. However, the adhesive layer used in this method is a thermoplastic polyimide film, and the film thickness that can be stably produced with the current polyimide film forming technology is limited to about 8 μm even at the thinnest. It is difficult to produce. In other words, when a polyimide metal foil laminate is used, there is a problem that it is difficult to make a thin film, and development of a technique for improving this problem has been desired.
Japanese Unexamined Patent Publication No. H5-222219 JP 2001-233973 A JP-A-6-100714 Japanese Patent Laid-Open No. 11-48423

  In order to realize fine wiring and multi-layer lamination in flexible printed circuit boards (FPC), improve the adhesion (peel strength) between metal foil and adhesive layer or between adhesive layer and polyimide in polyimide metal foil laminate. However, there is a problem that the conventional improvement method requires a manufacturing cost and cannot cope with the thinning of the polyimide layer (resin layer) expected to progress in the future.

  Accordingly, an object of the present invention is to provide a method for producing a polyimide metal foil laminate having improved adhesiveness (peel strength) for next-generation flexible printed wiring boards (FPC), which are becoming finer and more multilayered. It is.

  As a result of intensive studies to solve the above problems, the present applicant applied and dried a silane coupling agent and / or a siloxane oligomer on the surface of the polyimide film, and then applied a thermoplastic polyimide precursor varnish to form an adhesive polyimide film. After that, it was found that a polyimide metal foil laminate that can be applied to fine wiring and multilayer lamination can be produced by thermocompression bonding with a metal foil, thereby completing the present invention.

That is, the present invention is as follows. 1) A silane coupling agent and / or a siloxane oligomer is applied to one or both surfaces of a polyimide film and dried, and then a thermoplastic polyimide precursor varnish is applied to one or both surfaces of the polyimide film surface. To produce an adhesive polyimide film, and a method for producing a polyimide metal foil laminate, which is characterized by heat-pressing one or both sides of the adhesive polyimide film and a metal foil, more preferably,
2) The method for producing a polyimide metal foil laminate according to 1), wherein the silane coupling agent is hexamethyldisilazane (hereinafter sometimes abbreviated as HMDS), and
3) A polyimide metal foil laminate obtained from the production method described in 1) is provided.

  According to the present invention, the adhesion between the polyimide film and the adhesive layer formed on the surface thereof is improved, the peeling between the polyimide film and the adhesive layer is reduced, and the polyimide film and the metal foil are substantially removed. It becomes possible to improve the adhesiveness (peel strength). In addition, since the thickness of the silane coupling agent formed as a surface treatment can be easily controlled to 1 μm or less, the contribution of the silane coupling agent to the overall thickness of the polyimide metal foil laminate can be reduced, and the thin film thickness Can be held.

  In addition, since it is possible to form a surface treatment layer on a molecular unit basis, the shape is deformed by embedding an uneven shape (anchor layer) to improve adhesion on the polyimide film surface or metal foil surface. The peel strength can be stably improved without reducing the conventional adhesiveness. Moreover, since the cost of the HMDS treatment is low, the cost increase due to the surface treatment can be minimized.

  If the polyimide metal foil laminate of the present invention is used, the adhesiveness can be improved without performing surface treatment with a large apparatus such as plasma treatment, so that high peel corresponding to fine wiring and multilayer lamination can be achieved. It is possible to provide a polyimide metal foil laminate having strength at low cost. In addition, since the HMDS treatment only forms a layer on the polyimide film surface in units of one molecule, it is superior in reducing the thickness of the resin layer (insulating layer) and reduces the adhesion due to the surface anchor effect inherent in the polyimide film. It is possible to provide a polyimide metal foil laminate that can be bonded to the metal foil without any problem and has high adhesion.

  Hereinafter, the present invention will be described in detail.

  In the present invention, a silane coupling agent and / or a siloxane oligomer is applied to one or both surfaces of a polyimide film, dried, and then a thermoplastic polyimide precursor varnish is applied to one or both surfaces of the polyimide film surface to form an adhesive polyimide. A method for producing a polyimide metal foil laminate comprising producing a film, and heat-pressing one or both surfaces of the adhesive polyimide film and a metal foil.

  It does not specifically limit as a polyimide film which can be used for this invention method, It is possible to use the polyimide film which can obtain a commercial item. Examples include Kapton (registered trademark) film (manufactured by Toray DuPont Co., Ltd.), Apical (registered trademark) film (manufactured by Kaneka Corporation), Upilex (registered trademark) film (manufactured by Ube Industries, Ltd.), and the like. .

  It is also possible to produce a polyimide film from a polyamic acid solution that can be produced from a known diamine and acid dianhydride. In that case, it does not specifically limit as an example of a diamine component, It is possible to use the well-known diamine used for polyimide manufacture.

  Examples of the diamine component include m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, bis (3-aminophenyl) sulfide, (3-aminophenyl) ( 4-aminophenyl) sulfide, bis (4-aminophenyl) sulfide, bis (3-aminophenyl) sulfoxide, (3-aminophenyl) (4-aminophenyl) sulfoxide, bis (3-aminophenyl) sulfone, (3 -Aminophenyl) (4-aminophenyl) sulfone, bis (4-aminophenyl) sulfone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'- Diaminodiphenylmethane, 3,4'-diaminodiph Nylmethane, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, bis [4- (3-aminophenoxy) phenyl] methane, bis [ 4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- (3-aminophenoxy) phenyl] ethane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1 , 2-bis [4- (3-aminophenoxy) phenyl] ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane, 2,2-bis [4- (3-aminophenoxy) phenyl ] Propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophene) Xyl) phenyl] butane, 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (4- Aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1, 4′-bis (4-aminophenoxy) benzene, 4,4′-bis (3-aminophenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl,

Bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-amino Phenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfoxide, bis [4- (aminophenoxy) phenyl] sulfoxide, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 1,4-bis [4- (3-amino) Phenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) benzoyl] ben 4,4′-bis [3- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4′-bis [3- (3-aminophenoxy) benzoyl] diphenyl ether, 4,4′-bis [4- ( 4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] diphenylsulfone, bis [4- {4- (4 -Aminophenoxy) phenoxy} phenyl] sulfone, 1,4-bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) -α , Α-dimethylbenzyl] benzene, 1,3-bis (3- (4-aminophenoxy) phenoxy) benzene, 1,3-bis (3- (2-aminophenoxy) ) Phenoxy) benzene, 1,3-bis (4- (2-aminophenoxy) phenoxy) benzene, 1,3-bis (2- (2-aminophenoxy) phenoxy) benzene, 1,3-bis (2- ( 3-aminophenoxy) phenoxy) benzene, 1,3-bis (2- (4-aminophenoxy) phenoxy) benzene, 1,4-bis (3- (3-aminophenoxy) phenoxy) benzene, 1,4-bis (3- (4-aminophenoxy) phenoxy) benzene, 1,4-bis (3- (2-aminophenoxy) phenoxy) benzene, 1,4-bis (4- (2-aminophenoxy) phenoxy) benzene, 1 , 4-bis (2- (2-aminophenoxy) phenoxy) benzene, 1,4-bis (2- (3-aminophenoxy) phenoxy) benzene, 4- bis (2- (4-aminophenoxy) phenoxy) benzene,

1,2-bis (3- (3-aminophenoxy) phenoxy) benzene, 1,2-bis (3- (4-aminophenoxy) phenoxy) benzene, 1,2-bis (3- (2-aminophenoxy) Phenoxy) benzene, 1,2-bis (4- (4-aminophenoxy) phenoxy) benzene, 1,2-bis (4- (3-aminophenoxy) phenoxy) benzene, 1,2-bis (4- (2 -Aminophenoxy) phenoxy) benzene, 1,2-bis (2- (2-aminophenoxy) phenoxy) benzene, 1,2-bis (2- (3-aminophenoxy) phenoxy) benzene, 1,2-bis ( 2- (4-aminophenoxy) phenoxy) benzene, 1,3-bis (3- (3-aminophenoxy) phenoxy) -2-methylbenzene, 1,3-bis ( -(4-aminophenoxy) phenoxy) -4-methylbenzene, 1,3-bis (4- (3-aminophenoxy) phenoxy) -2-ethylbenzene, 1,3-bis (3- (2-aminophenoxy) Phenoxy) -5-sec-butylbenzene, 1,3-bis (4- (3-aminophenoxy) phenoxy) -2,5-dimethylbenzene, 1,3-bis (4- (2-amino-6-methyl) Phenoxy) phenoxy) benzene, 1,3-bis (2- (2-amino-6-ethylphenoxy) phenoxy) benzene, 1,3-bis (2- (3-aminophenoxy) -4-methylphenoxy) benzene, 1,3-bis (2- (4-aminophenoxy) -4-tert-butylphenoxy) benzene, 1,4-bis (3- (3-aminophenoxy) phenoxy) -2 5-di-tert-butylbenzene, 1,4-bis (3- (4-aminophenoxy) phenoxy) -2,3-dimethylbenzene, 1,4-bis (3- (2-amino-3-propylphenoxy) ) Phenoxy) benzene, 1,2-bis (3- (3-aminophenoxy) phenoxy) -4-methylbenzene, 1,2-bis (3- (4-aminophenoxy) phenoxy) -3-n-butylbenzene 1,2-bis (3- (2-amino-3-propylphenoxy) phenoxy) benzenebis (3-aminopropyl) tetramethyldisiloxane, bis (10-aminodecamethylene) tetramethyldisiloxane, bis (3 -Aminophenoxymethyl) tetramethyldisiloxane and the like. In addition, these can be used individually or in mixture of 2 or more types.

  Examples of the acid dianhydride component are not particularly limited. For example, pyromellitic dianhydride, 3-fluoropyromellitic dianhydride, 3,6-difluoropyromellitic dianhydride, 3,6 -Bis (trifluoromethyl) pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 2,2 ', 3,3'-benzophenone tetracarboxylic dianhydride, 3, 3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ″, 4,4 ″ -terphenyltetracarboxylic dianhydride, 3,3 ′ ″, 4,4 ′ ″ -Quaterphenyltetracarboxylic dianhydride, 3,3 "", 4,4 ""-kinkphenyltetracarboxylic dianhydride, 2,2 ', 3,3'-biphenyltetracarboxylic acid Dianhydride, methylene-4,4'-diph Luric dianhydride, 1,1-ethynylidene-4,4′-diphthalic dianhydride, 2,2-propylidene-4,4′-diphthalic dianhydride, 1,2-ethylene-4,4 ′ -Diphthalic dianhydride, 1,3-trimethylene-4,4'-diphthalic dianhydride, 1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,5-pentamethylene-4 , 4′-diphthalic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, difluoromethylene-4, 4'-diphthalic dianhydride, 1,1,2,2-tetrafluoro-1,2-ethylene-4,4'-diphthalic dianhydride, 1,1,2,2,3,3-hexa Fluoro-1,3-trimethylene-4,4'-diphthalic dianhydride, 1,1,2,2 3,3,4,4-octafluoro-1,4-tetramethylene-4,4′-diphthalic dianhydride, 1,1,2,2,3,3,4,4,5,5-deca Fluoro-1,5-pentamethylene-4,4′-diphthalic dianhydride, oxy-4,4′-diphthalic dianhydride, thio-4,4′-diphthalic dianhydride, sulfonyl-4, 4′-diphthalic dianhydride, 1,3-bis (3,4-dicarboxyphenyl) -1,1,3,3-tetramethylsiloxane dianhydride, 1,3-bis (3,4-di Carboxyphenyl) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenyl) benzene dianhydride, 1,3-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4- Bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,3-bi [2- (3,4-dicarboxyphenyl) -2-propyl] benzene dianhydride, 1,4-bis [2- (3,4-dicarboxyphenyl) -2-propyl] benzene dianhydride,

Bis [3- (3,4-dicarboxyphenoxy) phenyl] methane dianhydride, bis [4- (3,4-dicarboxyphenoxy) phenyl] methane dianhydride, 2,2-bis [3- (3 4-dicarboxyphenoxy) phenyl] propane dianhydride, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride, 2,2-bis [3- (3,4- Dicarboxyphenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride, Bis (3,4-dicarboxyphenoxy) dimethylsilane dianhydride, 1,3-bis (3,4-dicarboxyphenoxy) -1,1,3,3-tetramethyldisiloxane dianhydride, 2,3 6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6 7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4 Cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride 3,3 ′, 4,4′-bicyclohexyltetracarboxylic dianhydride, carbonyl-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene- , 4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,2-ethylene-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethynylidene -4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 2,2-propylidene-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1 , 1,3,3,3-hexafluoro-2,2-propylidene-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4′-bis (cyclohexane-1) , 2-dicarboxylic acid) dianhydride, thio-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) Dianhydride, 2, 2 '-Difluoro-3,3', 4,4'-biphenyltetracarboxylic dianhydride, 5,5'-difluoro-3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 6,6 '-Difluoro-3,3', 4,4'-biphenyltetracarboxylic dianhydride, 2,2 ', 5,5', 6,6'-hexafluoro-3,3 ', 4,4'- Biphenyltetracarboxylic dianhydride, 2,2'-bis (trifluoromethyl) -3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 5,5'-bis (trifluoromethyl)- 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 6,6′-bis (trifluoromethyl) -3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2, 2 ', 5,5'-tetrakis (trifluoromethyl)- 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 6,6′-tetrakis (trifluoromethyl) -3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride Anhydride, 5,5 ′, 6,6′-tetrakis (trifluoromethyl) -3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 5,5 ′, 6 6′-hexakis (trifluoromethyl) -3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride,

3,3′-difluorooxy-4,4′-diphthalic dianhydride, 5,5′-difluorooxy-4,4′-diphthalic dianhydride, 6,6′-difluorooxy-4,4 ′ Diphthalic dianhydride, 3,3 ′, 5,5 ′, 6,6′-hexafluorooxy-4,4′-diphthalic dianhydride, 3,3′-bis (trifluoromethyl) oxy 4,4′-diphthalic dianhydride, 5,5′-bis (trifluoromethyl) oxy-4,4′-diphthalic dianhydride, 6,6′-bis (trifluoromethyl) oxy-4, 4'-diphthalic dianhydride, 3,3 ', 5,5'-tetrakis (trifluoromethyl) oxy-4,4'-diphthalic dianhydride, 3,3', 6,6'-tetrakis ( Trifluoromethyl) oxy-4,4′-diphthalic dianhydride, 5,5 ′ 6,6′-tetrakis (trifluoromethyl) oxy-4,4′-diphthalic dianhydride, 3,3 ′, 5,5 ′, 6,6′-hexakis (trifluoromethyl) oxy-4,4 '-Diphthalic dianhydride, 3,3'-difluorosulfonyl-4,4'-diphthalic dianhydride, 5,5'-difluorosulfonyl-4,4'-diphthalic dianhydride, 6,6' -Difluorosulfonyl-4,4'-diphthalic dianhydride, 3,3 ', 5,5', 6,6'-hexafluorosulfonyl-4,4'-diphthalic dianhydride, 3,3'- Bis (trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 5,5′-bis (trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 6,6′-bis ( Trifluoromethyl) sulfonyl-4,4 ' Diphthalic dianhydride, 3,3 ′, 5,5′-tetrakis (trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 3,3 ′, 6,6′-tetrakis (trifluoromethyl) ) Sulfonyl-4,4′-diphthalic dianhydride, 5,5 ′, 6,6′-tetrakis (trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 3,3 ′, 5 5 ′, 6,6′-hexakis (trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 3,3′-difluoro-2,2-perfluoropropylidene-4,4′-diphthalic acid Dianhydride, 5,5′-difluoro-2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 6,6′-difluoro-2,2-perfluoropropylidene-4,4 '-Diphthalic dianhydride, 3 , 3 ′, 5,5 ′, 6,6′-hexafluoro-2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 3,3′-bis (trifluoromethyl) -2 , 2-perfluoropropylidene-4,4′-diphthalic dianhydride, 5,5′-bis (trifluoromethyl) -2,2-perfluoropropylidene-4,4′-diphthalic dianhydride 6,6′-difluoro-2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 3,3 ′, 5,5′-tetrakis (trifluoromethyl) -2,2-per Fluoropropylidene-4,4′-diphthalic dianhydride, 3,3 ′, 6,6′-tetrakis (trifluoromethyl) -2,2-perfluoropropylidene-4,4′-diphthalic dianhydride Product, 5,5 ′, 6,6′-tetrakis ( (Rifluoromethyl) -2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 3,3 ′, 5,5 ′, 6,6′-hexakis (trifluoromethyl) -2,2 -Perfluoropropylidene-4,4'-diphthalic dianhydride, 9-phenyl-9- (trifluoromethyl) xanthene-2,3,6,7-tetracarboxylic dianhydride, 9,9-bis (Trifluoromethyl) xanthene-2,3,6,7-tetracarboxylic dianhydride, bicyclo [2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride 9,9-bis [4- (3,4-dicarboxy) phenyl] fluorene dianhydride, 9,9-bis [4- (2,3-dicarboxy) phenyl] fluorene dianhydride, and the like. . These can be used alone or in admixture of two or more.

  The polyamic acid solution can be prepared by stirring the diamine and acid dianhydride in an appropriate organic solvent at an appropriate blending ratio. Here, as the organic solvent, known organic solvents that are generally used in the production of polyimide are not particularly problematic. Examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylformamide, and N, N. -Diethylacetamide, N, N-dimethylmethoxyacetamide, dimethyl sulfoxide, hexamethylphosphoramide, N-methyl-2-pyrrolidone, dimethyl sulfone, etc., a mixture of two or more of these, or a solvent thereof and benzene, What mixed toluene, xylene, benzonitrile, dioxane, cyclohexane, etc. suitably is mentioned.

  As a method for producing a polyimide film, the polyamic acid solution is usually extruded or cast on a casting drum or endless belt in a film form, dehydrated and closed on the drum or belt, and converted into polyimide. Furthermore, after hardening this to such an extent that it has self-supporting properties, the polyimide film can be peeled off from the drum or belt to produce a polyimide film. Here, the support on which the polyamic acid solution is applied is not limited to a casting drum or an endless belt, and can be peeled off after being applied on a glass substrate, a metal foil, a PET film, or the like.

  In the method of the present invention, the thickness of the polyimide film is not particularly limited, and is preferably 5 to 100 μm, more preferably 10 to 50 μm, and still more preferably about 25 μm. By using a polyimide film having such a thickness, the film itself has an appropriate rigidity, so that the transportability of the film is improved, and troubles such as breakage and twisting of the film can be avoided. Further, by making the thickness as thin as 10 to 50 μm, the drilling workability at the time of circuit processing and multilayer lamination is improved, which leads to cost reduction at the time of manufacturing a flexible printed wiring board.

  Examples of silane coupling agents that can be used in the method of the present invention include methyltrimethoxysilane, methyltriethoxysilane, hexamethyldisilazane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldichlorosilane, trimethylmethoxysilane, trimethylethoxysilane, Examples thereof include tridimethylchlorosilane, and hexamethyldisilazane is more preferable.

  The siloxane oligomer that can be used in the method of the present invention is preferably a siloxane oligomer having a reactive group.

  An example of a method for applying a silane coupling agent and / or a siloxane oligomer to the polyimide film surface in the method of the present invention is as follows. After thinly applying to the polyimide film surface in one direction by die coating with a gap of 100 μm or less, approximately 50 ° C. -By drying for about 10 minutes, a silane coupling agent layer controlled to a thickness of 1 μm or less can be formed. Here, the application method of the silane coupling agent is not limited to die coating, and roll coating, die lip coating, comma coating, dip coating, spin coating, spray coating, and the like are also applicable. Since the silane coupling agent can be formed on the film surface in units of one molecule, a thickness of about 1 to 50 nm is preferable. The drying temperature and time are not particularly limited as long as they are 200 ° C. or less, but drying at 50 to 100 ° C. for about 5 to 30 minutes is preferable.

  In the method of the present invention, as the thermoplastic polyimide, a known thermoplastic polyimide obtained from a known diamine and acid dianhydride can be used. Examples of these raw material diamines and acid dianhydrides include the above-mentioned raw materials for polyimide films. More preferably, a thermoplastic polyimide as shown below is mentioned as an example.

  Moreover, it is also a preferable aspect that a maleimide compound is further added to the thermoplastic polyimide precursor, more preferably the following formula:

What copolymerized the bismaleimide compound represented by these can be used. By copolymerizing the maleimide compound, an improvement in the elastic modulus of the polyimide is expected, and thus an improvement in heat resistance can be expected.

  In the method of the present invention, as a preferable example of the formation of the thermoplastic polyimide layer, it is thinly applied to the surface of the polyimide film on which the silane coupling agent is formed by a roll coater controlled to have a gap of 500 μm or less, and about 240 ° C. for about 10 minutes. It can be formed by drying. The thickness of the thermoplastic polyimide layer formed at this time is not particularly limited, but is preferably about 0.1 μm to 5 μm.

  The metal foil that can be used in the method of the present invention is not particularly limited, and examples thereof include copper foil, stainless steel foil, aluminum foil, gold foil, silver foil, and alloys thereof. Copper foil and copper alloy are preferable. Although the thickness of metal foil is not specifically limited, The thing of about 5 micrometers-50 micrometers is preferable from the transportability at the time of manufacture.

  As a preferred example of the method for heat and pressure bonding of the adhesive polyimide film and the metal foil, a three-layer laminator that feeds the metal foil from two places and the adhesive polyimide film from one place will be described as an example. The metal foil is fed from two places so that the adhesive polyimide film is sandwiched in a furnace heated up to about 270 ° C. by hot air, and the metal foil and the adhesive polyimide film are heated to 260 ° C. by a heating medium. Laminate with heat-resistant rubber roll. The residence time in the furnace of the metal foil and the adhesive polyimide film at this time is preferably within 1 minute. In addition, it is preferable to suppress the occurrence of pressure drop and wrinkles by controlling the gap between the two heat resistant rubber rolls to 500 μm or less.

  An example of more detailed conditions of the method of the present invention will be described with reference to FIG. First, after applying hexamethyldisilazane (hereinafter sometimes abbreviated as HMDS) thinly to the surface of a commercially available polyimide film with an applicator, it is quickly dried at a temperature of 50 ° C. in a nitrogen atmosphere and treated with a silane coupling agent. (Fig. 1 (a)). The HMDS layer formed here is preferably controlled to 1 μm or less. Next, a thermoplastic polyamic acid solution is further applied thereon with an applicator in the same manner, and then quickly dried and imidized at a temperature of 240 ° C. for 10 minutes in a nitrogen atmosphere, so that a thermoplastic polyimide having a thickness of about 2 to 3 μm. A layer is formed (FIG. 1 (b)). After bonding the roughened surface of 18 μm thick rolled copper foil (Nikko Materials Co., Ltd .: BHY series) to the adhesive polyimide film produced by the above process, 300 kg, 1 hour, 100 kg A polyimide metal foil laminate can be produced by bonding a polyimide film and a rolled copper foil by a vacuum hot press of / cm 2 (FIG. 1 (c)).

  In the present invention, the polyimide film surface is treated with a general-purpose HMDS-like silane coupling agent to improve the adhesion (peel strength) between the polyimide and the metal foil. It is possible to provide a polyimide metal foil laminate having high adhesion that can be laminated.

Hereinafter, the present invention will be described in more detail with reference to examples.
In addition, the evaluation performed by the Example and the comparative example was performed in accordance with the following method.
Measurement of peel strength (peel strength) of metal foil-clad laminate:
The measuring method is to follow the IPC-TM-650 method, and by etching the copper foil part, a copper foil pattern having a length of 50 mm and a width of 3.2 mm is formed in each of the MD and TD directions. It was carried out by peeling off the substrate at a speed of 50 mm / min in the 90-degree direction. Each was performed three times.

Example 1
Liquid hexamethyldisilazane (HMDS) was applied to one surface of a commercially available polyimide film (trade name: Apical (registered trademark) 25 NPI (thickness 25 μm), manufactured by Kaneka Corporation), and then at 50 ° C. in a nitrogen atmosphere. It was dried for 10 minutes to a thickness of 0.01 μm. Furthermore, 1,3-bis (3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride and 1,3- (3-aminophenoxy) benzene as a thermoplastic polyimide precursor in a dimethylacetamide solvent are used. (3-maleimidophenoxy) copolymerized benzene was applied and dried at 240 ° C. for 10 minutes in a nitrogen atmosphere to obtain an adhesive polyimide film. At this time, the thermoplastic polyimide layer had a thickness after drying of 2 to 3 μm. Thereafter, the roughened surface of the rolled copper foil (manufactured by Nikko Materials Co., Ltd., BHY series, thickness 18 μm) was bonded to the adhesive layer of the adhesive polyimide film, and then 300 ° C., 1 hour, 100 kg / cm ^2. The polyimide film and the rolled copper foil were bonded to each other by a vacuum heat press to obtain a polyimide metal foil laminate. The peel strength measurement between the copper foil and the polyimide layer of the obtained polyimide metal foil laminate was measured according to the method described above. The results are shown in Table 1.

Comparative Example 1
Except not performing HMDS process to a polyimide film, operation similar to Example 1 was performed and the polyimide metal foil laminated sheet was manufactured. The peel strength measurement between the copper foil and the polyimide layer of the obtained polyimide metal foil laminate was measured according to the method described above. The results are shown in Table 1.

  The location of the peeling interface is also shown in Table 1. From Table 1, the untreated copper-clad laminate has a polyimide / polyimide interface, whereas the HMDS-treated copper-clad laminate has not only a polyimide / polyimide interface but also a copper / polyimide interface. You can see that it is moving. This indicates that the adhesion between the polyimide film and the thermoplastic polyimide adhesive was improved by HMDS treatment on the polyimide film surface. Furthermore, as can be seen from Table 1, the peel strength at the copper / polyimide interface has shifted to the peel strength at the copper / polyimide interface in the HMDS-treated copper clad laminate, and the polyimide / polyimide interface has further improved. It can also be seen that the peel strength at is slightly improved.

  As described above, it was found that the adhesiveness (peel strength) was improved in the copper-clad laminate having the polyimide film surface treated with HMDS.

  With such a polyimide metal foil laminate with improved adhesiveness, it is possible to compensate for the apparent peel strength reduction due to finer wiring width and the peel strength reduction due to heat / pressure history. And multi-layer stacking can be supported. In addition, this developed technology can improve the adhesiveness by a simple method such as HMDS treatment, so that the current cost can be maintained.

1 shows the structure of an HMDS-treated polyimide film produced in an example. The structure of the adhesive polyimide film manufactured in the Example is shown. An example of the structure of the polyimide metal foil laminated board of this invention is shown.

Explanation of symbols

1 Commercial polyimide film 2 Hexamethyldisilazane (HMDS) treatment layer 3 Adhesive thermoplastic polyimide layer 4 Rolled copper foil (BHY series)

Claims (3)

After applying and drying a silane coupling agent and / or siloxane oligomer on one or both surfaces of the polyimide film, an adhesive polyimide film is manufactured by applying a thermoplastic polyimide precursor varnish on one or both surfaces of the polyimide film surface. A method for producing a polyimide metal foil laminate, wherein one or both surfaces of the adhesive polyimide film and a metal foil are heat-pressed. The method for producing a polyimide metal foil laminate according to claim 1, wherein the silane coupling agent is hexamethyldisilazane (HMDS). A polyimide metal foil laminate obtained from the production method according to claim 1.

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