High temperature cracking of tungsten polycide films on quartz substrate

Abstract

Investigation of high temperature cracking of tungsten polycide films on quartz reveals that the average thermal expansion mismatch stress and process-related local stress due to the interfacial roughening and voids may be major factors generating cracks in tungsten silicide. The silicide reaction and silicon crystallization at high temperature are responsible for interfacial roughening in silicon-rich silicide (WSi x>2.3 )and local voids in tungsten-rich silicide (WSi x<2.3 ): high temperature annealing of silicon-rich silicide on a-Si/quartz allows silicon growth into the silicide, resulting in the interfacial roughening and thus increasing the local stress near the tips of silicon intrusion; tungsten-rich silicide on a-Si/quartz produces interfacial voids during high temperature annealing, which initiates crack propagation on cooling.