Aluminum Voiding And Delamination Induced BY High Intrinsic Stress

Abstract

A typical robust metal stack consists of a Ti/TiN underlayer, aluminum, and a Ti/TiN top anti-reflective coating (ARC). This common film stack has been found to be susceptible to random yield loss based on the purity of the underlying titanium. The Ti purity ultimately changes the grain structure of the aluminum, resulting in higher intrinsic stress, delamination, and voiding, particularly in areas with dense via arrays. This paper will explain the potential mechanism for this phenomenon and propose a solution for how to prevent the metal voiding by modifying chamber conditioning.