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