| 摘要 |
<p>An electrostatic chuck (8) is provided having a plurality of small electrostatic structures (A, B) for holding an electrically conductive workpiece (10) forming a plate of a capacitor. Each electrostatic structure (A, B) includes a first thermally conductive single-crystal dielectric sheet (22), and a first electrode (23) in sheet form sandwiched between the first dielectric sheet and a second dielectric surface (24). The workpiece (10), typically a conductive or semiconductive wafer, is juxtaposed to the first dielectric sheet (22) of each electrostatic structure (A) and forms a second electrode. The second dielectric sheet (24), if thick, is used as a thermally conducting base plate which can be attached to a low pressure reactor (29). If the second dielectric (24) 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 a metal base plate (4) if the thermal expansion characteristics of the two elements are sufficiently matched. The first thermally conductive dielectric sheet (22) is preferably formed of sapphire, which is sufficiently thermally conductive to allow for rapid heat transfer between the base plate (4) and the workpiece (10). The electrodes (23) of different electrostatic structures (A, B) are held at different electrical potentials and a charge is maintained by this potential difference between selected electrostatic structures (A, B).</p> |
