US Patent 7267610 CMP pad having unevenly spaced grooves

A chemical mechanical polishing pad (100) having a circular polishing track (124) and a concentric center (116). The polishing pad (100) includes a polishing layer (104) having a groove pattern containing a plurality of grooves (128) each extending through the polishing track (124). The plurality of grooves have an angular pitch that varies in a circumferential direction about the concentric center (116) of the pad (100) and the radial pitch between all adjacent grooves (128) within the wafer track (124) is unequal.