Patent attributes
An electrostatic chuck 108 is provided on a lower electrode 106 provided inside a processing chamber 102 of an etching apparatus 100, and a conductive inner ring body 112a and an insulating outer ring body 112b are encompassing the outer edges of a wafer W mounted on the chuck surface. The temperatures of the wafer W and the inner and outer ring bodies 112a and 112b are detected by first˜third temperature sensors 142, 144 and 146. A controller 140 controls the pressure levels of He supplied to the space between the center of the wafer W and the electrostatic chuck 108 via first gas outlet ducts 114 and to the space between the outer edges of the wafer W and the electrostatic chuck 108 via second gas outlet ducts 116 and the quantity of heat generated by a heater 148 inside the outer ring body 112b based upon the information on the temperatures thus detected so that the temperatures of the wafer W and the inner ring body 112a are set roughly equal to each other.