A processing chamber having an improved sealing means is disclosed. The
processing chamber comprises a lower element, an upper element, and a
seal energizer. The seal energizer is configured to maintain the upper
element against the lower element to maintain a processing volume. The
seal energizer is further configured to generate a sealing pressure in a
seal-energizing cavity that varies non-linearly with a processing
pressure generated within the processing volume. In one embodiment, the
seal energizer is configured to minimize a non-negative net force against
one of the upper element and the lower element above a threshold value.
The net force follows the equation P2*A2-P1*A1, where P2 equals the
sealing pressure, P1 equals the processing pressure, A2 equals a
cross-sectional area of the seal-energizing cavity, and A1 equals a
cross-sectional area of the processing volume.