Patent ID: 7007919

Claim:
An apparatus comprising: a slit valve door adapted to seal a slit valve opening; an actuator coupled to the slit valve door and adapted to selectively move the slit valve door between a closed position in which the slit valve door seals the slit valve opening, and an open position in which the slit valve door does not seal the slit valve opening; a hard stop adapted to selectively move between a lock position in which the hard stop locks the slit valve door in the closed position and unlock position in which the hard stop allows the slit valve door to move between the closed position and the open position; and a controller coupled to the actuator and to the hard stop, and adapted to cause the actuator to move the slit valve door to the closed position and thereafter to cause the hard stop to move to the lock position so as to lock the slit valve door in the closed position; wherein the controller is adapted to cause a first compression between the slit valve door and the slit valve when the slit valve door is in the closed position and the hard stop has not yet locked the slit valve door in the closed position, and to cause a second compression between the slit valve door and the slit valve opening when the hard stop has locked the slit valve door in the closed position; and wherein the second compression is less than the first compression.