Patent ID: 7374477

Claim:
A polishing pad, comprising: a polishing piece having a polishing surface and a back surface and an aperture for the polishing surface to the back surface; a solid window situated in the aperture of the polishing piece, the window having a top surface that is flush with the polishing surface and a bottom surface that is flush with the back surface of the polishing piece and a thick region between the top surface and the bottom surface, the window including an indentation on its bottom surface, the indentation defining a recessed inner surface and a thinned region between the recessed inner surface and the top surface of the window; and a backing layer that includes an aperture, the backing layer being attached to the polishing piece at the back surface of the polishing piece so that the aperture of the backing layer is aligned to expose the indentation in the window, wherein the aperture in the backing layer is sized and shaped to circumscribe the indentation in the window so that the backing layer supports an outer region of the window's bottom surface, and wherein the thinned region is connected to the thick region and the thick region is connected to the polishing piece such that a portion of the top surface of the thinned region of the window is constrained from moving vertically relative to a portion of the polishing surface that surrounds the window.