Load lock control

摘要

A control for pressurizing a load lock. The control initiates pressurization of the loadlock interior by coupling a source of gas to the loadlock interior. A representative load lock includes a pressure sensor and multiple valves to atmosphere where at least one such valves is a passthrough valve for removal of and insertion of workpieces from and into a load lock interior. A second fast acting valve also opens to atmosphere. A pressure rise inside the loadlock interior is monitored and when the pressure reaches a threshold pressure above atmosphere the fast acting valve is opened to atmosphere. This second fast acting valve is configured to relieve overpressure from the passthrough valve prior to opening of said passthrough valve. Workpiece movement is accomplished with the aid of a robot which reaches into the loadlock interior as it is either depositing workpieces or retrieving them. This system and process minimizes particle contamination of the load lock interior as well as contamination in the region outside the loadlock near the passthrough valve and any scheduled workpieces.