Slotted retaining ring for polishing head and method of using

摘要

The present invention discloses a slotted retaining ring for use in a chemical mechanical polishing head which can be fabricated by providing a plurality of slot recesses in a bottom surface of the retaining ring. Each of the plurality of slot recesses may be formed in a tapered shape with a base portion adjacent to the outer periphery of the ring and a tip portion of a smaller width than the base portion adjacent to the inner periphery of the retaining ring. The tip portion of the tapered shape is normally spaced apart from the inner periphery such that excessive polishing of the wafer edge can be avoided. The present invention further discloses a method for chemical mechanical polishing a semiconductor wafer by using the slotted retaining ring for holding a polishing head therein.