Plasma altered layer model for plasma damage characterization of porous OSG films

Abstract

A plasma altered layer model was developed to characterize plasma damage in porous OSG (organosilicate glass) low-k dielectrics by taking into account the kinetics of radical diffusion, reaction, and recombination. A gap structure was designed to study plasma damage and validate the model. It consisted of two parallel rectangular Si spacers and a top optical mask to control the energy and intensity of ion, photon, and radical in the plasma. CO2 and O2 plasma-induced damages were found to depend on the radical concentration, the energy and intensity of VUV photons, the ion energy, and the substrate temperature. Overall, the results obtained from plasma damage studies were consistent with the prediction of the model. The application of the model was demonstrated in a study of He plasma pretreatment and damage formation in OSG films with varying carbon concentrations. Both treatments were found to be effective in improving the material resistance to plasma damage.