abstract |
The present disclosure is directed to a circuit board having a first polyimide coverlay and a second polyimide coverlay derived from 80 to 90 mole % 3,3',4,4'-biphenyl tetracarboxylic dianhydride, 10 to 20 mole % 4,4'-oxydiphthalic anhydride and 100 mole % 2,2'-bis(trifluoromethyl) benzidine or 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, a first imaged metal layer, a first electrically insulating layer, a second imaged metal layer, a polyimide bondply having a polyimide derived from 80 to 90 mole % 3,3',4,4'-biphenyl tetracarboxylic dianhydride, 10 to 20 mole % 4,4'-oxydiphthalic anhydride and 100 mole % 2,2'-bis(trifluoromethyl) benzidine, a third imaged metal layer, a second electrically insulating layer, a fourth imaged metal layer. |