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Polyimide Curing by Gamma Ray Irradiation

IP.com Disclosure Number: IPCOM000041976D
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

de Hodgins, OC: AUTHOR [+3]

Abstract

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.

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Polyimide Curing by Gamma Ray Irradiation

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. An important factor is that the wafers, after being spun with the polyimide and the adhesion promoter, should be carefully placed in a straining frame with a fixed distribution load. Once the wafer is placed in the straining frame, the unit is subjected to Gamma-Irradiation (Cobalt 60 source) for a sufficient period of time to initiate phase B. The curing is then completed and the wafer with polyimide and adhesion promoter (still under strain with a fixed distribution load) advances to stage C, where the polyimide is hard and almost polymerized. During phase C, new molecular bonds form about the originally deformed bonds, and with the fixed l...