Measurement method and measurement apparatus for measuring thickness of semiconductor wafer

A measurement apparatus for measuring a thickness of a semiconductor wafer comprising:

• an optical system configured to perpendicularly irradiate each of a sample wafer, which is a semiconductor wafer to be measured, and a reference wafer, which is a semiconductor wafer having a uniform thickness, with light to receive interference signals of the light reflected on front and back surfaces of the sample wafer and the reference wafer;
• a signal processor configured to perform frequency analysis of the interference signals received by the optical system to obtain peak positions of point spread functions of the sample wafer and the reference wafer;
• a calculator configured to calculate a thickness “tsample” of the sample wafer based on the peak position “x” of the sample wafer and the peak position “y” of the reference wafer obtained by the signal processor, and the thickness “treference” of the reference wafer;
• and
• a temperature adjustment mechanism configured to adjust at least one of temperatures of the sample wafer and the reference wafer.