Dry vacuum pumps: A method for the evaluation of the degree of dry

The drive towards dry vacuum pumping has occurred across the spectrum of va cuum applications from semiconductor manufacture to industrial processing. This brings with it a need to systematically evaluate and quantify the degr ee of cleanliness characteristic of any particular pump; currently, there i s no universally accepted method to perform this function. A methodology de veloped for repeatable measurements of pump cleanliness will be discussed. It utilizes residual gas analysis with carefully controlled pump conditions . This facilitates direct comparisons of the degree of cleanliness between pumps of the same and those of different design. Additionally, it allows fo r the assessment of methods (either in pump design or use) introduced to im prove cleanliness. (C) 2000 American Vacuum Society. [S0734-2101(00)11303-1 ].