Chemical mechanical polishing apparatus having a stepped retaining ring and method for use thereof

A polishing apparatus, comprising:

• a polishing pad capable to polish a substrate;
• a substrate support structure including
• an inner surface,
• a bottom surface, the bottom surface and inner surface forming a step, the step enabling a pad to rebound therein during polishing, and
• at least three tips in the step, the at least three tips capable to maintain a substrate outside of the step during polishing,
• the substrate support structure capable to rotate the substrate against the polishing pad;
• and
• a dispenser capable to dispense a slurry onto the pad.

A method, comprising:

• retaining a substrate with a substrate support structure, the substrate support structure having
• an inner surface,
• a bottom surface, the bottom surface and inner surface forming a step, the step enabling a pad to rebound therein during polishing, and
• at least three tips in the step, the at least three tips capable to maintain a substrate outside of the step during polishing;
• dispensing a slurry onto a polishing pad;
• and
• rotating the substrate support structure against the polishing pad.