PURPOSE: To prevent the contamination of a sputtering material by providing heaters which heat a wafer holder simultaneously with a wafer and heating the wafer holder, then removing the gas of the wafer holder in a load locking chamber or pretreating chamber of a sputtering device.

CONSTITUTION: An atm. pressure is first maintained in the load locking chamber 6a and a front door 7a is opened together with the front heater 4. The wafer holder 1 set with the wafer 2 to be treated is mounted to a holding arm of the wafer holder 1. After the wafer holder 1 is mounted to the arm, the front door 7a is closed and the load locking chamber 6a is evacuated by a vacuum pump. The front heater 4 and the rear heater 5 are energized when a prescribed vacuum degree is attained. The wafer holder 1 and the wafer 2 are then heated at the assigned temp. for a prescribed period of time and are thereby subjected to a gas removing treatment, by which the sputtering materials are prevented from contamination.