A New Technique for Via Plugging through the Selective Chemical Vapor Deposition of Aluminum

Abstract

A new technique for selective via plugging in order to obtain perfectly planarized multilevel metallization is demonstrated through the chemical vapor deposition (CVD) of aluminum. It has been found that the selectivity between aluminum and silicon oxide can be enhanced by sputter-deposition of ultrathin layers of palladium and cobalt on aluminum interconnection lines prior to patterning of via holes. It was found that the coating of aluminum oxide with these noble metals was mainly responsible for the selectivity enhancement. This new technique was demonstrated to be highly suitable for actual device fabrication.