Abstract: A method for evaluating the physical consumption of a polishing pad of a CMP apparatus provided with an eddy current sensor that is configured to sense a distance with a substrate on which a layer to be processed extends. The method includes: generating a magnetic field adapted to induce eddy currents in the layer; acquiring an eddy current signal generated by the layer in response to the magnetic field; calculating an average value of the eddy current signal in the initial time frame; comparing the average value with a pre-set threshold value; and determining a maintenance condition of the polishing pad based on a result of the comparison.