Abstract: An electrostatic chuck (1) for holding a semiconductor wafer (5) comprises a dielectric layer (4) on a supporting electrode (2). The wafer is clamped flat against the dielectric layer when a potential difference is applied between the wafer and the electrode. The dielectric is loaded with a thermally conductive material to improve the dissipation of heat generated in the wafer during a processing treatment such as exposure to an electron beam. The dielectric also has charge retention properties so that the wafer can be transported still clamped to the chuck without the need for a permanent electrical connection nor additional mechanical clamping members.

Abstract: 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.

Abstract: An electrostatic chuck for holding a simiconductor wafer flat in a charged particle beam machine has thermally conductive portions for supporting the wafer. An electrically conductive member, for example a grid, has parts which extend between the thermally-conductive portions and is separated from the wafer by a dielectric layer. The wafer is clamped against the chuck by the electrostatic force set up across the dielectric layer when a potential difference is applied between the conductive wafer and the conductive member. Heat generated in the wafer by the bombardment of charged particles can be dissipated readily via the thermally conductive portions. The wafer can be electrically contacted at its back surface if the portions are also electrically conductive. To enhance thermal conduction away from the wafer, the conductive portions can protrude from the dielectric layer.