Abstract: A low particulate vacuum chamber semiconductor wafer input/output valve minimizes the particulate generation by taking advantage of a camming motion at the instant of closing to insure that the valve closes normal to the reaction chamber wall. This eliminates any friction between a glandular seal in the vacuum chamber wall. As the valve closes, it strikes a stop which causes a 90 degree change in direction of the valve forcing it into tape cut. This change of direction is accomplished through a combination of an upper motion of a backing plate, and a spring-loaded linkage in stock. As the gate closes there is some particulte generated at the interface of the valve plate and the stop. This is handled by placing the area of contact outside the transportation path for the semiconductor wafer.