| 摘要 |
An apparatus and method to position a wafer (16) onto a wafer holder (200) and to maintain a uniform wafer temperature is disclosed. The wafer holder or susceptor (200) comprises a recess or pocket (202) whose surface (229) is concave and includes a grid containing a plurality of grid grooves (222) separating protrusions (220). The concavity and grid grooves define an enclosed flow volume (248) between a supported wafer (16) and the susceptor surface, as well as an escape area, or total cross- sectional area of the grid grooves (222) opening out from under the periphery of the wafer (16). These are chosen to reduce the wafer slide and curl during wafer drop-off and wafer stick during wafer pick-up, while improving thermal uniformity and reducing particle problems. In another embodiment, centering locators (250 or 252) in the form of thin, radially placed protrusions are provided around the edge of a susceptor pocket (202) to reduce further the possibility of contact between the wafer and the outer shoulder (206) of the susceptor. These features help to achieve temperature uniformity, and therefore quality of the process result, across the wafer during processing.
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