method and device with reduced ausschußrate during the processing of workpieces in vacuum

摘要

A method and apparatus for reducing the incidence of product contamination during processing of the product in a vacuum chamber. By providing soft-start valves in the vacuum and vent lines, and by properly driving said soft-start valves, it is possible to reduce the gas flow rates from and into the vacuum chamber to such a low level, that dust- like particles remaining in the chamber from prior product processing steps is not disturbed and allowed to settle upon the product then being treated.