Abstract: In a chemical-mechanical polishing (CMP) process, semiconductor substrates are rotated against a polishing pad in order to planarize substrate layers. The condition of the polishing pad directly affects the polishing rate of material removal and uniformity of removal from the semiconductor wafer. Conditioning of the polishing pad surface with an abrasive improves polishing uniformity and rates, however, it has the detrimental affect of removing a quantity of pad material. A method and apparatus for monitoring polishing pad wear during processing is developed to extend the pad's useful life, and maintain pad uniformity. This is accomplished in the present invention by measuring and monitoring the diminished pad thickness using a non-intrusive measurement system, and creating a closed-loop system for adjusting the chemical-mechanical polishing tool process parameters.

Abstract: A method and apparatus for monitoring polishing pad wear during processing is developed to extend the pad's useful life, and maintain pad uniformity. This is accomplished in the present invention by measuring and monitoring the diminished pad thickness using a non-intrusive measurement system, and creating a closed-loop system for adjusting the chemical-mechanical polishing tool process parameters. The non-intrusive measurement system consists of an interferometer measurement technique utilizing ultrasound or electromagnetic radiation transmitters and receivers aligned to cover any portion of the radial length of a polishing pad surface. The measurement system is sensitive to relative changes in pad thickness for uniformity, and to abrupt changes such as detecting wafer detachment from the CMP wafer carrier.

Abstract: A wafer carrier assembly including a subassembly for in-situ nondestructive pad conditioning, characterized by continuously cleansing the pad surface with an energized fluid. The fluid may be abrasive in nature, such as a slurry, or non-abrasive, such as DeIonized (DI) water. In addition, the fluid may be of a type known to assist in removing slurry and/or residual materials from a pad surface and followed by a DI water rinse. The chemical may be either liquid or gas.