Volume 2, Issue 6 (June 2005)
A Preliminary Mathematical Removal-Rate Model for Si CMP
Based on the experimental removal rate data of silicon chemical-mechanical polishing (CMP), we conducted mathematical analysis on effects of surface roughness, asperities, and different length scales on material removal rate. A preliminary physical model was developed enabling consideration of mechanical and chemical removal during the Si CMP process. This model is compared with experimental results obtained through a tabletop polisher. Research results showed that the removal rate decreased with time and eventually became constant. The model has a higher prediction power when the surface roughness is high. However, with a smooth surface, the asperity height does not take a major role in the model. In such, the chemical interactions become important.