| 摘要 |
An electrostatic chuck is provided having a plurality of small electrostatic structures for holding an electrically conductive workpiece forming a plate of a capacitor. Each electrostatic structure includes a first thermally conductive single-crystal dielectric sheet, and a first electrode in sheet form sandwiched between the first dielectric sheet and a second dielectric surface. The workpiece, typically a conductive or semiconductive wafer, is juxtaposed to the first dielectric sheet of each electrostatic structure and forms a second electrode. The second dielectric sheet, if thick, is used as a thermally conducting base plate which can be attached to a low pressure reactor. If the second dielectric is a thin sheet, then it is mounted to a thermally conductive metal base plate through which heat can be controllably conducted. The resultant electrostatic structure may optionally be brazed to the metal base plate if the thermal expansion characteristics of the two elements are sufficiently matched. The first thermally conductive dielectric sheet is preferably formed of sapphire (Al2O3), which is sufficiently thermally conductive to allow for rapid heat transfer between the base plate and the workpiece. The first electrodes of different electrostatic structures are held at different electrical potentials (typically of several thousand volts difference) and a charge is maintained by this potential difference between selected electrostatic structures.
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