Polishing pad with radially extending tapered channels

摘要

A polishing pad having a polishing surface with radially extending tapered channels is disclosed. The polishing surface includes an inner radius within an outer radius, and the channels extend from the inner radius to the outer radius. Preferably, the outer radius is spaced from an outer circumferential edge of the polishing surface, the inner radius is an inner circumferential edge of the polishing surface, and the channels taper laterally and vertically at the outer radius. The channels are dimensioned and configured to direct slurry from the inner radius to the outer radius. The channels can be shaped with opposing sidewalls that are parallel in a first portion and diagonally converge in a second portion to form a sunburst pattern, or alternatively, with opposing sidewalls that continuously curve in a first rotational direction to form a starfish pattern. A polishing method includes positioning a wafer over the outer radius while introducing a slurry to facilitate polishing the wafer, and positioning the wafer inside the outer radius while introducing a cleaning fluid to facilitate cleaning the wafer.