Optimization of Slurry and Technological Parameter on Chemical Mechanical Polishing of Titanium Dioxide Film for IC

Abstract

Titanium dioxide (TiO2) has shown a great potential to be used in resistive random access memory, capacitor, solar cell and sensor. However, the surface topography as-deposited TiO2 film cannot meet the requirement of IC. Therefore, TiO2 film must be flattened before apply into semiconductor device. In this paper, chemical mechanical polishing (CMP) was used for polishing TiO2 film. We studied the effect of slurry pH of polishing from the viewpoint of chemical we found the removal rate with acid slurry is lower than the removal rate obtained by alkali slurry. The effect of the process parameter such as down force, platen rotation rate were also studied in detail and found the removal rate still exist when there is no pressure and velocity, hence Preston equation was slightly modified. Final, the surface roughness was reduced from 36Aå to 1.2Aå, and the removal rate was up to 38.2nm/min.