Copolymer For Direct Bonding In Single Or MultiLevel Applications
Original Publication Date: 1979-Nov-01
Included in the Prior Art Database: 2005-Feb-20
Polyamic acid copolymer is prepared from 4-aminophenyl ether and a mixture of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 1,2,4,5-benzenetetracarboxylic dianhydride. The starting materials are very highly purified. The anhydrides are measured to provide a total of close to a 1:1 mole ratio with the amine, and the reaction is carried out in an anhydrous polar solvent such as DMSO or other.