Effects of Disk Design and Kinematics of Conditioners on Process Hydrodynamics during Copper CMP

Abstract

This study focuses on determining the effect of conditioner disk design, kinematics, and pressure on the slurry distribution under the wafer as measured by the slurry film thickness between the wafer and the pad during actual polishing. Film thicknesses are measured using dual emission UV-enhanced fluorescence, which for thickness measurement requires the slurry to be tagged with two different fluorescent dyes. Results indicate that the wafer is tilted toward the center of the pad and that the extent of wafer tilt is a strong function of conditioning disk pressure. Increasing the oscillation frequency of the conditioner disk or the rotation rate decreases the slurry film thickness and the film thickness increases with slurry flow rate.