Wired circuit board

• US 7,638,873 B2
• Filed: 11/30/2006
• Issued: 12/29/2009
• Est. Priority Date: 12/01/2005
• Status: Active Grant

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Ishii, Jun, Funada, Yasuhito
• Primary Examiner(s): LAM, CATHY FONG FONG
• Application Number:
  US11/606,021
• Publication Number:
  US 20070128417A1
• Time in Patent Office: 1,125 Days
• Field of Search: 174250-258, 257/698, 257/700
• US Class Current: 257/698
• CPC Class Codes: H05K 1/056 the metal substrate being covered by an organic insulating layer
• CPC Class Codes: H05K 2201/0317 Thin film conductor layer; Thin film passive component
• CPC Class Codes: H05K 2201/0338 Layered conductor, e.g. layered metal substrate, layered finish layer or layered thin film adhesion layer
• CPC Class Codes: H05K 2201/09845 Stepped hole, via, edge, bump or conductor
• CPC Class Codes: H05K 2203/0723 Electroplating, e.g. finish plating
• CPC Class Codes: H05K 3/388 by the use of a metallic or inorganic thin film adhesion layer
• CPC Class Codes: H05K 3/44 Manufacturing insulated metal core circuits or other insulated electrically conductive core circuits H05K3/0058, H05K3/4608, and H05K3/4641 take precedence
• CPC Class Codes: Y10T 428/24917 including metal layer

Abstract

A wired circuit board is provided which can reduce transmission loss with a simple layer structure and also features excellent long-term reliability by preventing the occurrence of an ion migration phenomenon between a metal foil and an insulating layer to improve the adhesion between the metal foil and the insulating layer and the conductivity of a conductor. A metal supporting board is prepared and a first metal thin film is formed on the metal supporting board by sputtering or electrolytic plating. A metal foil is formed on the first metal thin film by electrolytic plating. A second metal thin film is formed over the metal foil and the metal supporting board by electroless plating or sputtering. An insulating base layer is formed on the second metal thin film. A conductive pattern is formed as a wired circuit pattern on the insulating base layer. An insulating cover layer is formed on the insulating base layer to cover the conductive pattern.

Claims

1. A wired circuit board comprising:

a metal supporting board;

a first metal thin film formed on the metal supporting board;

a metal foil formed on the first metal thin film;

a second metal thin film formed on the metal foil;

an insulating layer formed on the second metal thin film; and

a conductive pattern formed on the insulating layer.

2. A wired circuit board according to claim 1, wherein the metal foil is made of copper, and the second metal thin film is made of at least one metal selected from the group consisting of nickel, chromium, and an alloy of nickel and chromium.