Patent ID: 7486407

Claim:
A polishing pad surface shape measuring device comprising a measuring element which can contact the polishing pad, a first detector which measures the distance to the polishing pad surface or the distance to the measuring element in a non-contact manner, a second detector which measures the distance to the surface of a reference member that has a standard degree of flatness, a movable element which slides along a guide mechanism, and which carries the measuring element, the first detector and the second detector, a driving part which drives the movable element in the direction of diameter of the polishing pad, position detection means for detecting the position of the movable element in the direction of diameter of the polishing pad, means for switching between a state in which the distance to the measuring element is measured by the first detector in a state in which the measuring element is caused to contact the polishing pad, and a state in which the distance to the surface of the polishing pad is measured by the first detector in a state in which the measuring element is separated from the polishing pad, and measurement means for measuring at least one value selected from a set consisting of the circular-conical vertical angle formed by the polishing pad surface, the groove depth and the pad thickness, using the distance output from the first detector, the distance output from the second detector, and the output of the position of the movable element in the direction of diameter of the polishing pad.