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Abstract

A plasma process method and apparatus for use with a vacuum instrument having a vacuum chamber evacuated by an oil free high vacuum pump to a base pressure below about 1 Pa. A gas buffer chamber in fluid communication with the plasma chamber, the gas buffer chamber having a volume about 1/500 to 1/2000 of the volume of the vacuum chamber. A valve between the plasma chamber and the gas chamber permits flow between the gas chamber and the plasma chamber, wherein, upon opening the valve, gas is admitted into the plasma chamber and pressure in the plasma chamber rises temporarily to between about 10 and about 200 Pa and plasma ignition can be obtained when the plasma excitation device is energized simultaneously. A flow restriction between the gas source and the gas chamber has a maximum flow rate therethrough of about 25 sccm. (standard cubic centimeters per minute) or less so that pressure in the plasma chamber remains between about 1 and about 7 Pa after plasma ignition to maintain plasma conduction and to avoid overloading or heating of the high vacuum pump.

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First Claim