The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 12, 2001
Filed:
Aug. 31, 1998
Yasuhito Funada, Osaka, JP;
Toshihiko Omote, Osaka, JP;
Nitro Denko Corporation, Osaka, JP;
Abstract
The present invention provides a circuit substrate and a circuit-formed suspension substrate comprising the circuit substrate, the circuit substrate comprising a metal foil substrate and an insulating layer composed of a polyimide resin formed on the metal foil substrate, wherein the polyimide resin is one obtained by the reaction of (A) p-phenylene diamine and (B) acid anhydrides of (a) 3,4,3′,4′-biphenyltetracarboxylic acid dianhydride and (b) 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane. Since a coefficient of linear thermal expansion of the polyimide resin is close to that of various metal foils, the circuit substrate causes no cracking on the resin layer and scarcely causes warpage, and the resin layer does not separate.