Polyimide Curing by Gamma Ray Irradiation
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Circuit wafers with spun-coated polyimide may be placed under strain and partially cured using Gamma irradiation, removed from the source of strain and finish cured while retaining orientation of the polyimide. Standard curing of spun polyimide by the thermo-cycling method can be improved by the application of Gamma-Irradiation (Cobalt 60 source), with a decrease in the amount of residual stresses, mostly due to thermo-stresses due to the thermo-cycling process. Polyimides have an amine-type hardener and a compatible plasticizer. Initially, in phase A of the curing process, the mixture of these constituents will be liquid; however, after a few hours the polymerization process phase B is initiated and a semicured polyimide which has the consistency of "soft rubber eraser" is obtained.