Analysis of sapphire- chemical mechanical polishing using digital image processing

Abstract

This study investigated the contact interface behavior between a wafer and a polishing pad in sapphire- chemical mechanical polishing (CMP) for considering the improvement of the removal rate. In our previous study we clarified that the linear velocity ratio, defined as the ratio of slurry flow velocity to pad linear velocity, remarkably affected the stability of the removal rate. The effect of the linear velocity ratio was discussed from the viewpoints of the slurry type. It was found that the slurry type changed the slurry film thickness between the wafer and the polishing pad. The relationship between the slurry film thickness and the surface asperity of the polishing pad was found to affect the linear velocity and the removal rate. As a result, we concluded the linear velocity ratio was an effective parameter for considering the CMP mechanism.

Keywords

• sapphire- cmp
• contact interface
• linear velocity ratio
• removal rate
• slurry film thickness
• contact angle of slurry