Patent ID: 6835442
Filing Date: 2004-12-28
Classification: H05K,Y10S,Y10T

Abstract:
A flexible printed board comprising:an electrodeposited copper foil which has not been subjected to a surface roughening treatment and has an arithmetic average roughness Ra of less than 0.3 &mgr;m; a zinc-based metallic layer provided on the electrodeposited copper foil in an amount of 0.259 to 0.340 mg/dm2; a chromium oxide layer which is formed in an amount of 0.032 to 0.05 mg/dm2 on the zinc-based metallic layer; and a polyimide resin layer formed by imidation of a polyamic acid provided on the chromium oxide layer, and has a linear thermal expansion coefficient of 10 to 30Ã—10âˆ’6 (1/K) and exhibits a softening point in the temperature range from 300 to 400Â° C.