Dynamic particulate characterization of a vacuum load‐lock systemJournal of Vacuum Science & Technology A (1989)
Particle contamination is an important issue for the development of vacuum interface technology. In this work the relative particle levels between a clean room and a vacuum chamber are compared; once vacuum conditions are reached no particles are detected implying that vacuum environments are intrinsically cleaner than clean rooms. Then the dynamics of particles are systematically studied in a vacuum load‐lock chamberd u r i n g pump down. The relationship between particle count and turbulence is developed through the Reynolds number. Higher particle counts are observed under turbulent conditions and lower particle counts are obtained by reducing the pumping and venting speed. The nature of the chamber ambient is also shown to be a critical parameter. A large reduction in particle density is obtained by preparing the chamber by backfilling with dry nitrogen as compared with (moist) clean room air, even if pumped under turbulent conditions. This and other data suggests a correlative effect between moisture and pumping rate. Particular methodologies of alternate pumping and venting cycles are used to demonstrate lower particle densities. Recommendations are discussed.
Publication DateSeptember, 1989
Citation InformationDegang Chen, Thomas Seidel, Steve Belinski and Susan Hackwood. "Dynamic particulate characterization of a vacuum load‐lock system" Journal of Vacuum Science & Technology A Vol. 7 Iss. 5 (1989) p. 3105 - 3111
Available at: http://works.bepress.com/degang-chen/1/