Polishing pad surface shape measuring instrument, method of using polishing pad surface shape measuring instrument, method of measuring apex angle of cone of polishing pad, method of measuring depth of groove of polishing pad, CMP polisher, and method of manufacturing semiconductor device

摘要

The main sensor 15 measures the distance Lm to the surface of the pad 2a, and the sub-sensor 16 measures the distance Ls to the surface of the reference block 12. What is actually taken as the measured value is the value of (Lm+Ls). The reference block 12 is used in order to give a reference position for measuring the surface position of the pad 2a. Accordingly, correct measurements can be performed even if the position of the movable element 9 should fluctuate, for example, as a result of deformation of the guiding and holding plate 7 or guide 8. When the motor 11 is caused to rotate, the ball screw 10 rotates, so that the movable element 9 moves leftward and rightward, and the distance to the pad 2a is measured. From the measured data of this distance, the circular-conical vertical angle, groove depth, thickness, and the like of the pad 2a are determined.