PURPOSE: To prevent the generation of a recombination reaction with one-time cleaned metallic conductor of oxygen molecules and oxygen atoms decomposed and the re-oxidation of the oxygen molecules and oxygen atoms by introducing a reducing gas into a sputtering device together with argon gas for sputtering.

CONSTITUTION: Air in a vacuum tank 1 is evacuated and the inside of the vacuum tank 1 is brought to a vacuum state, argon gas is introduced, and high-frequency voltage is applied between and upper electrode 5 and a lower electrode 6 by an RF power supply, thus generating plasma between the upper electrode 5 and the lower electrode 6. Argon ions in plasma flow on the surface of a board 7, and the surface of the board 7 is sputtered. Sputtered and liberated copper, aluminum, and oxygen adhere on a shutter 8 mounted between both electrodes and are evacuated from the exhaust port 2, but oxygen near the board 7 is bonded with hydrogen introduced near the surface of the board 7 to form water and is evacuated.