MODIFIED WEIBULL FAILURE THEORY FOR SIZE EFFECT PREDICTION OF BRITTLE THIN FILM

摘要

A brittle thin film bonded to a substrate is common in MEMS components. At the edge of the interface, high stress gradients exist. It has been observed that mechanical strengthening of the thin film with decreasing film size occurs due to two constraints, namely, the microstructural constraint and the geometrical constraint. Consideration of both these constraints is required to properly predict the size effect impact on the strength of a brittle thin film. In this paper, a statistical approach is developed to predict the size effect of a brittle thin film on a substrate.