Substrate Independent Elastic Modulus of Thin Low Dielectric Constant Materials

Abstract

The elastic modulus of a variety of porous low dielectric constant thin films with porosities in the range of 24–47% and thicknesses between 148 and 235 nm is calculated using the Oliver–Pharr method, an intrinsic thin film model based on the Li‐Vlassak method, and finite element simulations in the elastic regime by taking the tip imperfections into account. It is shown that the substrate effects are significant even at shallow indentation depths and strongly depend on the nanoindenter geometry. Elastic modulus values extracted from the intrinsic thin film model and finite element simulations, although based on different approaches, are found to be very similar and independent of the nanoindenter geometry.