PURPOSE: To enable a thermal deformation control of good accuracy by arranging a displacement measuring device and heating device on the opposite face of at least one part of the upper/lower surface plates of a double face polishing device for wafer, and performing the control for turning a heater ON-OFF based on the displacement value of the surface plate.
CONSTITUTION: A distortion gage 31 of a displacement measuring mean and heater 30 of a heating means are arranged in more than one pair at least at the specified position on the face opposite to at least one part of the polishing faces of upper/lower surface plates l, 2 of a both face polishing device, and the ON-OFF of the heater 30 are performed based on the detection quantity with the detection of the displacement. In the case of a temperature rise with the polishing face side being heated according to the progress of polishing, therefore, the face of the opposite side thereof is heated by the external heat source of a heater 30, etc., in the form of compensating this temperature rise and the temperature distributions of the upper and lower faces of the surface plate 1 are made equal. So the temperature distribution inside the surface plate becomes about symmetrical vertically and the thermal deformat ion control for minimizing the thermal deformation of the surface plate 1 is executed.
OKUNO KOJI
HATTORI KAZUO
OMURA MASAKI
SAKAMA HIROSHI
ISHII SHINJI
