| 摘要 |
<p>A method and apparatus for securely clamping a substrate (24) to an electrostatic chuck (20) during processing of a substrate. The method generally includes the steps of forming an initial electrostatic clamping force between the electrostatic chuck and the substrate, modifying the initial electrostatic clamping force when an rf voltage is applied to the electrostatic chuck during processing, and restoring the initial electrostatic clamping force with an offset voltage applied to the electrostatic chuck. The electrostatic chuck (20) has at least one electrode (22a/b) and a dielectric on the surface of the electrode for supporting a substrate. A voltage source (30) is coupled to the electrode for electrostatically clamping the substrate (24) to the surface of the electrostatic chuck with an initial electrostatic force. An rf source (31) is coupled to the electrode for applying rf voltage to the electrostatic chuck and causing a change in the initial electrostatic force. A control system (37) is coupled to the rf source and voltage source for producing an offset in response to the change in the initial electrostatic force, thereby restoring the initial electrostatic force.</p> |
