Large-electromigration-resistance copper interconnect technology for sub-half-micron ULSI's

Abstract

A large-electromigration-resistance copper interconnect technology has been developed using the low-kinetic energy particle process. It was found that grains as large as 100 mu m grow in the copper film formed on SiO/sub 2/ upon the thermal annealing performed after the film growth process. The resistivity of the copper film is as low as 1.78 mu Omega cm at room temperature, which is almost identical to the bulk resistivity. The electromigration lifetime of the copper interconnect is three to five orders of magnitude larger than that of Al-Si-based alloy interconnects. Furthermore, a novel accelerated-electromigration-testing method has been developed to evaluate such long-lifetime copper interconnects within a short period of test time. The method has made it possible to perform comparative studies of various interconnect materials in a very efficient way to establish large-electromigration-resistance interconnection technology.<>