Patent ID: 7621798

Claim:
A chemical mechanical polishing pad, comprising: an outer layer that includes a polishing surface, a thinned region defined by a recess on a bottom surface of the pad, a first thick region surrounding the thinned region, the first thick region not vertically extendable, a second thick region surrounding the first thick region, and a third thick region surrounding the second thick region, the second thick region defining one or more compression mechanisms configured to make the thinned region and the first thick region movable relative to the third thick region in a direction parallel or substantially parallel to the polishing surface, wherein the thinned region and the first thick region are part of a window in the outer layer and the one or more compression mechanisms are integrated into the outer layer and abut the window, wherein the one or more compression mechanisms allow the window to move in a direction parallel or substantially parallel to the polishing surface, and wherein the one or more compression mechanisms and the outer layer are made of different materials.