Polishing monitoring method and polishing apparatus

摘要

The present invention provides a method of monitoring a change in film thickness during polishing using an eddy current sensor. This method includes acquiring an output signal of the eddy current sensor as a correction signal value during water-polishing of a substrate, during dressing of the polishing pad, or during replacement of the polishing pad, calculating a correcting amount from a difference between the correction signal value and a predetermined correction reference value, calculating an actual measurement signal value by subtracting the correction amount from the output signal of the eddy current sensor when polishing a substrate having a conductive film, and monitoring a change in thickness of the conductive film during polishing by monitoring a change in the actual measurement signal value.