摘要 |
An electrostatic chuck (4) for holding a workpiece (2) in a low pressure environment. The chuck (4) comprises a dielectric substrate (8) fabricated of a material that does not contain polar molecules that are free to move in response to the application of an electric field (V). This avoids the problem of the workpiece (2) sticking to the chuck (4) after the energizing voltage (V) has been removed. In an environment in which high temperatures are employed, the dielectric (8) is coupled to a metallic heat conductor (23) via a plurality of metallic pins (22) that couple heat and are free to flex in response to motion caused by differentials in thermal expansion coefficients between the metal (23) and the dielectric (8). The chuck (4) is preferably fabricated from two substantially planar dielectric members (30,33) sandwiched around a brazing compound (11,13) which become electrically conductive electrodes (11,13) after the assembly is heated and then cooled. <IMAGE> |