Evaluation of slurry flow behavior in chemical mechanical polishing of hard to process material

Relationship between slurry flow behavior in slurry film thickness and surface texture of polishing pad

Abstract

This study investigates the slurry flow behavior in the contact surface between the substrate and the polishing pad in chemical mechanical polishing (CMP) of hard-to-process materials. In the evaluation of slurry flow behavior, the digital image correlation method was used. In this paper, we tried to estimate the slurry flow behavior in the slurry film thickness direction by using the phenomenon that the light transition ratio is affected by the slurry film thickness. Furthermore, we discussed the reliability of estimated slurry film thickness compared with the polishing pad surface texture. As a result, we can estimate the slurry flow velocity at the neighborhood of the substrate surface during the CMP, and the removal rate increase with the increase of the slurry flow velocity ratio.