| abstract |
The present disclosure is directed to a circuit board having a first electrically insulating layer, a first imaged metal layer and a first polyimide coverlay derived from 100 mole % 3,3',4,4'-biphenyl tetracarboxylic dianhydride, 20 to 90 mole % 2,2'-bis(trifluoromethyl) benzidine, and 10 to 80 mole % 4,4'-oxydianiline. The circuit board does not have an adhesive layer between the first imaged metal layer and the polyimide coverlay. |