Application of Aluminum Oxide to Integrated Circuits Fabrication

Formation characteristics of an aluminum oxide grown by an ``aluminum + water reaction´´ method are reviewed and its etching rates in some solutions are reported. The aluminum oxide protects the A1 against some chemicals, and serves, by covering the A1 surface with the aluminum oxide, to reduce the frequency of integrated circuit (IC) failures due to aluminum corrosion. Application to epoxy-encapsulated ICs shows that it greatly reduces the frequency of failures in a steam pressure test. Another application to IC chips with gold bumps shows that it drastically reduces the incidence of A1 corrosion which otherwise occurs during bump formation. This method is simple, requires no change in conventional processing, and gave satisfactory results in spite of the presence of glass defects.