New Coupling Method for Polyimide Adhesion to LSI Surface

A new coupling method f r improving polyimide adhesion to LSI surfaces is presented. The method utilizes an alumi-num organic chelate compound instead of an aminosilane coupler commonly used for polymer to glass fiber. Adhesive strength is evaluated by peel strength. Peel strength of PIQ ~, a polyimide type resin, to aluminum chelate treated SiO2 sur-face is not found to be degraded even after exposure to a 300 h pressure cooker test. Aluminum chelate also improves the adhesion strength of PIQ cured at temperatures ranging from 200 ~ to 450 ~ In addition, PIQ coupled with aluminum chelate acts to protect aluminum etallization from corrosion. This new method makes it possible to fabricate more liable LSI devices. The use of polyimide resin as a multi level insulator and protective coating for LSI has become increas-ingly important. Since polyimide film is formed by spinning a prepolymer solution onto a wafer followed by thermal curing, it provides ideal wafer flatness and permits excellent step coverage of overlapping metal conductors. Multi level metall ization with polyimide in