摘要 |
A polishing system has a polishing pad, a wafer retainer for pressing an insulating layer formed on a semiconductor wafer against polishing slurry spread over a polishing pad and a measuring apparatus for measuring the thickness of different portions of the insulating layer, and the measuring apparatus has measuring electrodes embedded in the polishing pad, a first calibration electrode also embedded in the polishing pad and a second calibration electrode embedded into the lower surface of the wafer retainer, wherein the first calibration electrode and the measuring electrodes are opposed to the second calibration electrode and an electrode formed in a dicing area of the semiconductor wafer during the polishing so that the measuring apparatus determines the thickness at the different portions on the basis of a first capacitance between the first calibration electrode and the second calibration electrode and a second capacitance between the measuring electrodes and the electrode in the dicing area.
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