| 摘要 |
Disclosed is an aromatic copolyimide film prepared by chemical conversion of a copolyamide acid solution obtained by copolymerization of an aromatic tetracarboxylic acid component comprising from 30 to 50 mole % of biphenyltetracarboxylic acid dianhydride, 50 to 70 mole % of pyromellitic acid dianhydride, 60 to 80 mole % of p-phenylenediamine and 20 to 40 mole % of 4,4'-diaminodiphenyl ether. The aromatic copolyimide film has a low coefficient of thermal expansion, low water absorption, a low coefficient of hygroscopic expansion, high mechanical strength and is readily etchable making it suitable for use an advanced electronic substrate. |
