US Patent 7059949 CMP pad having an overlapping stepped groove arrangement

A polishing pad (104, 300) having an annular polishing track (152, 320) and a plurality of groups (160, 308) of grooves (112, 304) repeated circumferentially about the rotational center (128) of the pad. The plurality of grooves in each group are arranged along a trajectory (164, 312) in an offset and overlapping manner so as to provide a plurality of overlapping steps (172, 316) within the annular polishing track. The groups may be arranged in spaced-apart or nested relation with one another.