摘要 |
An electrostatic chuck (1) for holding a semiconductor wafer (5) has a dielectric layer (4) on an electrode (2) and surrounded by an annulus (3) for electrically contacting the wafer. The wafer is located on the dielectric layer but at its periphery contacts the annulus. By applying a potential difference (V) from an external voltage source between the annulus and the electrode the wafer is electrostatically clamped against the chuck. The wafer is displaced rotationally, perpendicularly, and/or laterally on the chuck while the voltage is still connected. This enchances the clamping effect due to charge retention in the dielectric layer after the voltage source has been disconnected.
|