MODELING OF IONIZED PHYSICAL VAPOR DEPOSITION OF COPPER

摘要

We use computer simulations to study ionized physical vapor deposition, with ionized magnetron sputter deposition of copper as the primary system of interest. The effects of ion energy and ion angular flux distributions on the evolution of sub-micron features during IPVD are explored using the EVOLVE simulator. Our goal is to develop semi-quantitative engineering relationships that explain the trends in experimental responses to changes in operating conditions. A sticking-factor model is used to describe deposition by neutrals. The sticking-factor of incident Cu atoms can depend on arrival angle and energy. Copper ions can also become part of the growing film. Energy and angular dependent sputter yields for both copper and argon ions are taken alternately from MD simulation results and a semi-empirical model. Sputtered material is ejected from the surface, tracked through the gas phase, and allowed to redeposit. Redeposition is also modeled via a sticking-factor based approach. The redistribution of material results in non-intuitive profiles and complex relationships between final profiles and process parameters, such as sample bias and neutral-to-ion flux ratio.