Published online by Cambridge University Press: 01 February 2011
This paper presents the stress stability of thin films for MEMS structural and sacrificial layers. The average residual stresses of the thin films were monitored via wafer curvature measurement over a long period of time. Poly-Si, poly-SiGe, poly-Ge and thermally growth SiO2 films are found to be stable in humid environments. Moisture makes LPCVD and TEOS-based PECVD SiO2 films more compressive over time. Multi-layer thin film stress is modeled with the same methodology used to derive the Stoney Equation [1].