Fracture and Deformation of Capped Multilayer Dielectric Structures

摘要

The fracture and deformation properties of thin films of low dielectric constant (low-k) silsesquioxane spin-on glasses are investigated. These materials are softer, more compliant and more susceptible to fracture than the chemical vapor deposited silica and silicon nitride currently used as dielectrics in microelectronic devices. Here the effects of capping spin-on glass films with an overlayer of a hard, stiff, fracture-resistant film of silicon nitride are investigated. The results are analyzed with a model for stress-corrosion cracking in multilayer structures that incorporates a reduction in the mechanical energy release rate for fracture of the low-k film deriving from the constraint of the cap.