Retaining rings, and associated planarizing apparatuses, and related methods for planarizing micro-device workpieces

Retaining rings and associated planarizing apparatuses, and related methods for planarizing micro-device workpieces are disclosed herein. A carrier head configured in accordance with one embodiment of the invention can be used to retain a micro-device workpiece during mechanical or chemical-mechanical polishing. In this embodiment, the carrier head can include a retaining ring carried by a workpiece holder. The retaining ring can include an inner surface, an outer surface, and a base surface extending at least partially between the inner and outer surfaces. The retaining ring can further include at least one annular groove and a plurality of transverse grooves. The annular groove can be positioned adjacent to the base surface between the inner and outer surfaces. The plurality of transverse grooves can extend from the inner surface of the retaining ring to the annular groove in the base surface.