Abstract: A porous polishing pad for use chemical/mechanical planarization of semiconductor wafers is provided with a transparent section formed in a section of the porous polishing pad by direct injection of a polymeric material into a modified portion of the pad. The modified section may be either a low density area, or may be created by removing a complete vertical section of the pad. The injected polymer forms an integral window with the pad by flowing into the matrix of the pad at the pad/window interface. No additional reinforcement is required to hold the window in place; however, adhesive and/or another impervious layer may be attached behind the window for additional support. In an alternative embodiment, a separate and distinct window-plug is inserted into a cutout section of the pad, and bonded to the pad by one or more binding film layers on the back, non-working surface of the pad.