Relationship between polishing pad surface temperature and removal rate in sapphire-chemical mechanical polishing

Abstract

This study was performed to investigate the relation between removal rate and polishing pad surface temperature in chemical mechanical polishing (CMP) of sapphire substrate (wafer). Contact image analysis was used to evaluate the polishing pad surface asperity. In particular, we examined the following two variables experimentally during sapphire-CMP: (i) the rotational speed of the wafer and the platen (polishing pad), and (ii) the setting temperature of the platen controlled by the chiller unit. This paper discusses the cross-relationships between polishing pad surface temperature, asperity, and removal rate. The results indicated that the hardness and asperity of the polishing pad were affected by changing the pad surface temperature. Furthermore, the removal rate increased with increasing number of contact points between the wafer and the polishing pad.