# US 8,771,496 B2 · Process for producing metal composite film

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- Number: US 8,771,496 B2
- Document ID: US8771496B2
- Status: Granted
- Kind: B2
- Application number: 12/227,330
- Filed: 2006-05-17
- Published: 2009-12-17
- Granted: 2014-07-08
- Earliest claimed: 2006-05-17
- Assignees: Pi R&D Co., Ltd.
- Applicants: Eiji Nagata; Hiroyuki Ishii
- Inventors: Eiji Nagata; Hiroyuki Ishii
- Web page: https://patentgrep.com/patent/US8771496B2

## CPC

- H05K 1/036: {Multilayers with layers of different types}
- B32B 15/08: of synthetic resin
- B32B 27/28: comprising synthetic resins not wholly covered by any one of the sub-groups {B32B27/30 - B32B27/42}
- B32B 27/34: comprising polyamides
- C23C 18/1653: {Two or more layers with at least one layer obtained by electroless plating and one layer obtained by electroplating}
- C23C 18/2066: {Use of organic or inorganic compounds other than metals, e.g. activation, sensitisation with polymers}
- C23C 18/31: Coating with metals
- C23C 28/00: Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
- B32B 2274/00: Thermoplastic elastomer material
- B32B 2457/08: PCBs, i.e. printed circuit boards
- H05K 1/0346: {containing N}
- H05K 1/0393: {Flexible materials (H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups)}
- H05K 3/181: {by electroless plating (adhesives therefor H05K3/387)}
- H05K 2201/0129: Thermoplastic polymer, e.g. auto-adhesive layer; Shaping of thermoplastic polymer
- H05K 2201/0154: Polyimide
- Y10T 428/264: Up to 3 mils
- Y10T 428/265: 1 mil or less
- Y10T 428/269: including synthetic resin or polymer layer or component
- Y10T 428/31681: Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A metal composite film having an excellent heat resistance and adhesion, suited for flexible printed circuit boards capable of forming fine wirings, as well as a production process thereof, is disclosed. The metal composite film comprises an insulating film; a thermoplastic polyimide layer(s) formed on at least one surface of the insulating film; and metal layers formed on the surface of each of the thermoplastic polyimide layer(s), which metal layers are formed by electroless plating and then by electrolytic plating, respectively. Since this metal composite film has an excellent heat resistance and adhesion, and maintains the excellent adhesion after forming fine wirings, it is suitably used as a high density flexible printed circuit board having fine circuits.

## Claims

### Claim 1

A process for producing a composite metal film, which process comprising the steps of:
forming a thermoplastic polyimide layer on at least one surface of an insulating film;
forming a first copper layer by electroless plating so that the first copper layer is disposed directly on said thermoplastic polyimide layer; and
forming a second copper layer directly on said first copper layer by electrolytic plating, wherein
said thermoplastic polyimide layer comprises a polyimide resin having carboxyl groups, wherein
said thermoplastic polyimide layer is formed by applying a solvent-soluble polyimide solution on the insulating film and drying the solution, and wherein
said thermoplastic polyimide is a polyimide obtained by polycondensation between a tetracarboxylic dianhydride component(s) including at least bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride and a diamine component(s) including at least a diamine having a carboxylic group(s).

### Claim 2 (depends on 1)

The process according to claim 1, wherein said insulating film is made of one selected from the group consisting of polyethylene terephthalate, polynaphthalene terephthalate, polyphenylene sulfide, polyphenylene ether resins, polyamide resins, aromatic polyamide resins, polyimide resins, fluorocarbon polymers and liquid crystal polymers.

### Claim 3 (depends on 1)

The process according to claim 1, wherein said insulating film has a thickness of 5 μm to 500 μm.

### Claim 4 (depends on 1)

The process according to claim 1, wherein said thermoplastic polyimide layer comprises a polyimide block copolymer.

### Claim 5 (depends on 1)

The process according to claim 1, wherein said thermoplastic polyimide layer has a thickness of 1 μm to 20 μm.

### Claim 6 (depends on 1)

The process according to claim 1, wherein a total thickness of both said first copper layer and said second copper layer is 1 μm to 40 μm.