Floating high vacuum seal cartridge

A method of allowing a shaft to penetrate an aperture in a process chamber while maintaining a pressure differential between the process chamber and the exterior environment comprising:

• disposing a fixed seal housing against the process chamber, the fixed seal housing comprising a first central opening aligned with the aperture;
• disposing a floating seal cartridge beneath the fixed seal housing, where the space between the fixed seal housing and the floating seal cartridge defines an interface, wherein the floating seal cartridge comprises a second central opening;
• disposing the shaft through the second central opening, the first central opening and the aperture;
• and
• creating a first air bearing between the floating seal cartridge and the shaft in the second central opening and a second air bearing between the floating seal cartridge and the fixed seal housing at the interface.

An apparatus for moving a payload within a process chamber, comprising:

• a shaft passing through an aperture in a wall of the process chamber;
• a mechanical contact bearing to support the shaft, disposed outside the process chamber;
• a fixed seal housing, having a first central opening through which the shaft passes, an upper surface affixed to an outer surface of the wall, and a lower surface, the fixed seal housing comprising
• a housing pressurized air port for connection to a source of pressurized air;
• a housing differential vacuum pumping port for connection to a pump;
• one or more housing air channels in communication with the housing pressurized air port and terminating at the lower surface to deliver pressurized air;
• and
• one or more housing vacuum channels in communication with the housing differential vacuum pumping port and terminating at the lower surface to evacuate pressurized air;
• a floating seal cartridge, having a second central opening through which the shaft passes, an upper surface disposed proximate to the lower surface of the fixed seal housing wherein the space therebetween defines an interface, and a lower surface, the floating seal cartridge comprising
• one or more cartridge air channels, disposed in the floating seal cartridge, connecting the upper surface of the floating seal cartridge to the second central opening, such that pressurized air from the interface is supplied to the second central opening;
• and
• one or more cartridge vacuum channels, disposed in the floating seal cartridge, connecting the interface and the second central opening, wherein pressurized air is evacuated from the second central opening and delivered to the interface;
• wherein a first air bearing is created between the floating seal cartridge and the fixed seal housing at the interface and a second air bearing is created between the floating seal cartridge and the shaft at the second central opening.