Polishing pad thickness measuring method and polishing pad thickness measuring device

摘要

A polishing pad thickness measuring method measures the thickness of a polishing pad 14 attached to an upper surface of a surface plate 12. The polishing pad thickness measuring method measures a first distance 98 between an upper surface of the polishing pad 14 and a reference position 88 on a vertical line perpendicular to the surface of the polishing pad 14 and a second distance 100 between an upper surface of the surface plate 12 and the reference position on the vertical line, and calculates the thickness of the polishing pad 14 from the difference between the first and second distances 98 and 100.