Residual stress and fracture in thick tetraethylorthosilicate (TEOS) and silane-based PECVD oxide films

This paper reports residual stress measurements and fracture analysis in thick tetraethylorthosilicate (TEOS) and silane-based plasma enhanced chemical vapor deposition (PECVD) oxide films. The measured residual stress depended strongly on thermal process parameters; dissolved hydrogen gases played an important role in governing intrinsic stress. The tendency to form cracks was found to be a strong function of film thickness and annealing temperature. Critical cracking temperature was predicted using mixed mode fracture mechanics, and the predictions provide a reasonable match to experimental observations. Finally, engineering solutions were demonstrated to overcome the problems caused by wafer bow and film cracks. The results of this study should be able to provide important insights for the design of fabrication processes for MEMS devices requiring high temperature processing of films