A study on the nitridation of barrier liner contribution to galvanic corrosion of copper bondpad

Abstract

Galvanic corrosion of copper bondpad is studied with various copper barrier liner compositions in a unbiased highly accelerated stress test (uhast) condition. It is observed that the delamination at the bimetallic interface between the barrier liner and bulk copper has a strong dependence of N/Ta ratio of the liner. The delamination mechanism is explained and attributed to the galvanic corrosion, due to the presence of electrochemical potential difference between the barrier liner and bulk copper, which is shown to be significantly suppressed by increasing the nitrogen content composition of the liner.