| 摘要 |
PROBLEM TO BE SOLVED: To detect preferably change in torque currents even if the change in the torque currents is small, so as to improve accuracy in polishing end-point detection.SOLUTION: A polishing device 100 comprises a first electric motor 14 that rotation-drives a polishing table 12, and a second electric motor 22 that rotation-drives a top ring 20 which holds a semiconductor wafer 18. The first electric motor 14 comprises three-phase winding. The polishing device 100 comprises: a current detection portion 24 that detects three-phase currents; a rectification calculation portion 28 that rectifies the detected three-phase currents detected by the current detection portion 24 and adds rectified signals to the currents and then outputs the currents; and an end-point detection portion 29 that detects, on the basis of change in output of the rectification calculation portion 28, a polishing end-point showing that polishing of a surface of a semiconductor wafer 18 is ended.SELECTED DRAWING: Figure 1 |
