MECHANICAL-STRESS OF CVD-DIELECTRICS

A qualitative model is presented to understand the intrinsic stress in CVD-dielectrics. In addition to well-known factors such as ion bombardment and cross-linking, adsorbance effects have been taken into account. Low surface mobility and low density of reactants in the adsorbed phase are predicted to in.crease intrinsic tensile stress, fitting the experimental data well. An interlayer with differing properties to the bulk film exists and, for LPCVD-nitride, the thickness of this interlayer is influenced by process temperature, pressure, and dichlorosilane flow.