Patent ID: 8263193

Claim:
A vacuum treatment method comprising the steps of: heating a substrate disposed inside a deposition chamber under a reduced pressure atmosphere using a heating device, supplying a raw material gas to the deposition chamber, supplying electric power to a discharge electrode disposed in a position facing the substrate, and plasma depositing a silicon-based film on the substrate, wherein the silicon-based film deposition is conducted with a gap between the substrate and the discharge electrode set to a value of not less than 4.5 mm and not more than 7.5 mm, in a state in which a temperature difference between the substrate and the discharge electrode is not more than 30 degrees C., so as to control an SiH.sub.2 to SiH ratio, and, wherein, the deposition is conducted with a deposition pressure inside the deposition chamber set to a value of not less than 150 Pa and not more than 500 Pa.