Patent ID: 7359069

Claim:
A polishing pad surface shape measuring device comprising a first detector which measures the distance to the surface of the polishing pad, 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 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, 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, wherein at least one end of the reference member is held by a mechanism that allows displacement of the movable element in the driving direction and bending in this direction.