Retaining ring with flange for chemical mechanical polishing

A retaining ring comprising:

• a generally annular body having a top surface, a bottom surface, an inner diameter surface, and an outer diameter surface, wherein the bottom surface is configured to contact a polishing pad during polishing and the outer diameter surface includes a vertical surface, a tapered section and an outwardly projecting flange having a lower surface parallel to the top surface of the annular body, the vertical surface is adjacent to the bottom surface and the tapered section extends upwardly and outwardly from the vertical surface to the lower surface of the flange.