Patent ID: 6344308
Filing Date: 2002-02-05
Classification: H05K

Abstract:
A method of manufacturing a flexible circuit board comprising a polyimide insulating layer having land access holes and a conductor circuit layer provided thereon, comprising the steps of:(a) applying a polyimide precursor varnish to one side of a conductor circuit metal foil and drying to produce a polyimide precursor layer; (b) forming the land access holes in the polyimide precursor layer by a photolithographic process comprising: forming a land access hole pattern resist layer over the polyimide precursor layer; etching the land access hole pattern resist layer to produce the land access holes; and removing the land access hole pattern resist layer; (c) subsequent to forming the land access holes, patterning the conductor circuit metal foil by a subtractive process to produce the conductor circuit layer; and (d) imidating the polyimide precursor layer to produce the polyimide insulating layer.