# US 8,465,656 B2 · Method for manufacturing a printed circuit board and a printed circuit board obtained by the manufacturing method

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- Number: US 8,465,656 B2
- Document ID: US8465656B2
- Status: Granted
- Kind: B2
- Application number: 12/733,105
- Filed: 2008-06-23
- Published: 2010-06-10
- Granted: 2013-06-18
- Earliest claimed: 2007-09-10
- Assignees: Sumitomo Metal Mining Co., Ltd.
- Applicants: Harumi Nagao; Yoshiyuki Asakawa; Kenji Ikeuchi
- Inventors: Harumi Nagao; Yoshiyuki Asakawa; Kenji Ikeuchi
- Web page: https://patentgrep.com/patent/US8465656B2

## CPC

- H05K 3/067: {Etchants}
- C23C 22/52: Treatment of copper or alloys based thereon
- C23C 22/58: Treatment of other metallic material
- C23F 1/18: for etching copper or alloys thereof
- C23F 1/28: for etching iron group metals
- H05K 3/26: Cleaning or polishing of the conductive pattern
- H05K 3/388: {by the use of a metallic or inorganic thin film adhesion layer}
- H05K 2201/0338: Layered conductor, e.g. layered metal substrate, layered finish layer or layered thin film adhesion layer
- H05K 2201/0761: Insulation resistance, e.g. of the surface of the PCB between the conductors
- H05K 2203/0796: Oxidant in aqueous solution, e.g. permanganate
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- 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)
- C23F: NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE (working metal by laser beams B23K26/00; desurfacing by applying flames B23K7/00; working of metal by electro-erosion B23H; producing decorative effects by removing surface material, e.g. by engraving, by etching, B44C1/22; electrolytic etching or polishing C25F); INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25

## Abstract

A method for manufacturing a printed circuit board enables a metal residue between wirings to be removed inexpensively without side etching of a copper layer while having sufficient insulation reliability for micro wiring working. The method includes forming a base metal layer directly at least on one face of an insulator film without an adhesive, and a copper coat layer formed on the base metal layer to form adhesiveless copper clad laminates, then forming a pattern on the adhesiveless copper clad laminates by an etching method. The etching method includes a process of etching treatment for the adhesiveless copper clad laminates with an iron (III) chloride solution or a copper (II) chloride solution containing hydrochloric acid and then, a process of treatment with an acid oxidant containing permanganate and acetic acid.

## Claims

### Claim 1

A method for manufacturing a printed circuit board, comprising: forming a base metal layer directly at least on one surface of an insulator film without an adhesive, and a copper coat layer on the base metal layer to form adhesiveless copper clad laminates, and then forming a pattern on the adhesiveless copper clad laminates by an etching method, characterized in that the etching method for the adhesiveless copper clad laminates includes a process of etching treatment with an iron (III) chloride solution or a copper (II) chloride solution containing hydrochloric acid, and then a process of treatment with an acidic oxidant containing permanganate and acetic acid.

### Claim 2 (depends on 1)

The method for manufacturing a printed circuit board according to claim 1, further comprising a process of removing a manganese compound by a manganese residue remover after the treatment process by the acidic oxidant.

### Claim 3 (depends on 1)

The method for manufacturing a printed circuit board according to claim 1, wherein the base metal layer is comprised of at least one type of metal or an alloy made up of two types or more, selected from the group consisting of Ni, Cu, Mo, Ta, Ti, V, Cr, Fe, Co, and W.

### Claim 4 (depends on 1)

The method for manufacturing a printed circuit board according to claim 1, wherein the acidic oxidant is a solution containing a permanganate ratio of 0.05 to 10% by weight and an acetic acid ratio of 0.05 to 20% by weight.

### Claim 5 (depends on 1)

The method for manufacturing a printed circuit board according to claim 1, wherein the insulator film is a resin film of at least one type or more, selected from the group consisting of polyimide film, polyamide film, polyester film, polytetrafluoroethylene film, polyphenylenesulfide film, polyethylenenaphthalate film, and liquid crystal polymer film.