Edge sealing structure for substrate in low-pressure processing environment

Substrates, such those used for fabricating semiconductor, data storage, flat-panel display, and optoelectronic devices, are supported for processing in vacuum (i.e., low-pressure) chambers on chucks that typically include clamps for securing the substrates. Some substrate processing operations such as physical and chemical vapor deposition processes benefit from controlled thermal transfers between the chucks and the substrates. A gas sealed between the chucks and substrates is often used as a conductive medium for enhancing the thermal transfers and for regulating the substrate temperature during both active heating and cooling operations. A low-pressure processor for processing substrates includes a chuck that engages the substrates' peripheries for purposes of clamping, sealing, and centering the substrates on chuck bodies. For accomplishing all three purposes, a mechanical clamp can be arranged with two sealing regions. One of the sealing regions seals the clamp to a chuck body or an extension of the chuck body, and another of the sealing regions engages a peripheral edge surface of a substrate for sealing the clamp to the substrate. The second sealing region includes an inclined seating surface that engages a front edge of the substrate's peripheral edge surface and divides a clamping force into a first component that presses the substrate against the chuck body and a second component that centers the substrate on the chuck body. The peripheral engagement of the substrate exposes substantially the entire front surface of the substrate to processing and exposes substantially the entire back surface of the substrate to a heat-transfer gas for enhancing thermal transfers between the substrate and the temperature-regulated chuck body.