The Study to Minimize the Variation of Polishing Time According to the Pad Used Time

Abstract:
Keep uniform thickness of films on processed wafer within pad lifetime is crucial in current CMP process. Polishing time for each wafer tends to change with pad lifetime that may cause problems such as dishing. To track root cause of polishing time variation with pad lifetime, in this study, we examined pad surface by measuring surface roughness, pore volume, and contact area. It is revealed that polishing time variation is strongly dependent on types of slurry and pad surface. Correlation between types of slurry and pad surface was also observed. Keywords: polishing time, pad surface roughness, pore volume, process condition.