摘要 |
A pressure sealed chamber such as a load lock for a apparatus for processing substrates is operated with a guide plate spaced from a substrate supported therein so as to form a gap which covers the substrate surface to be protected from contamination by moisture condensing in the chamber during the rapid evacuation thereof. During the evacuation of the chamber, by either pumping or venting, clean dry gas is introduced through an orifice in the center of the plate so as to flow outwardly from the edge of the gap at a pressure sufficient to displace or otherwise prevent gas borne moisture condensate in the chamber from entering the gap and contaminating the surface to be protected of the substrate. During the evacuation of the chamber, gas is introduced through the gap at a flow rate less that of the evacuating gas.
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