Effect of slurry application/injection schemes on slurry availability during chemical mechanical planarization (CMP)

Effect of slurry applicationinjection schemes on slurry availability during CMP was investigated. A new ultraviolet enhanced fluorescence system was developed to measure slurry film thickness at the retaining ring bow wave for standard pad center area application and novel slurry injection methods. As the novel slurry injection system was placed adjacent to the retaining ring on the pad surface, it generated statistically thicker bow waves (up to 104 percent) in 7 out of 8 cases at different sliding velocities, slurry flow rates and ring pressures, providing more slurry availability for the pad-retaining ring interface. Slurry savings associated with the novel slurry injection system was estimated to range between 8 and 48 percent depending on specific process conditions.