PURPOSE: To form a film free of impurities and having a desired composition in the plasma producing device by providing an insulating member and a metallic seal member for keeping airtightness to a member for insulating electrodes from one another.
CONSTITUTION: An insulating ring 6 is arranged respectively between a cathode part 2 and a cylindrical tube 3, between the tube 3 and a first intermediate electrode 4, between the electrode 4 and a second intermediate electrode 5 and between the electrode 5 and a flange 11 to set the pressure in a film forming space at about 10-8Torr The insulating ring 6 consists of a ring main body 61 consisting of ceramics (aluminum nitride, etc.), a flange 62 of stainless steel and a seal 63 of copper, silver, etc. An H-shaped groove is formed over the whole circumference of both ends of the main body 61, the flange 62 is inserted into the groove and joined, and the seal 63 is put outside the flange. Consequently, a vacuum vessel is kept at a higher vacuum than before, and the remaining gas is minimized.
KAWAMATA KATSUHIDE
OOYAMAGUCHI MAKIKO
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