Patent ID: 7070476

Claim:
A chemical mechanical polishing (CMP) system for polishing a sample with a polishing agent and monitoring the sample, the CMP system comprising: a polishing table; a polishing pad arranged over the polishing table; a sample carrier arranged to hold the sample over the polishing pad of the polishing table, the polishing pad and sample carrier being arranged to receive a polishing agent between the sample and the polishing pad and to polish the sample by moving the polishing pad and the sample carrier relative to each other; and a measurement device for obtaining information regarding the polishing pad while the sample is being polished, wherein the measurement device includes an AC voltage source; a sensing coil coupled with the AC voltage source so that the AC voltage source is operable to induce an AC voltage on the sensing coil; an impedance meter coupled with the sensing coil that detects a change in the AC voltage on the sensing coil; a memory having programming instructions; and a processor coupled with the memory, the processor and memory being adapted for causing the AC voltage to be induced on the sensing coil and analyzing the change in the AC voltage on the sensor to obtain the information regarding the polishing pad.