Endpoint detector for a chemical mechanical polishing system

摘要

The disclosure relates to an endpoint detector (40) for a substrate chemical-mechanical polishing apparatus (14) have drive motors (20,26) in which a signal indicative of the instantaneous material removal rate from the substrate (16) is summed or integrated to provide a new line of the total power used. The signal is generated by a monitor (100) which measures a motor parameter such as torque or current draw. The resulting sum is compared by a comparator (122) to a baseline sum stored in memory (122) and known to yield the desired polishing to predict the polishing endpoint to control apparatus.