Abstract: An electrostatic chuck has a substrate, an insulating layer disposed on the substrate for attracting a workpiece thereto, and an electrode interposed between the substrate and the insulating layer. The insulating layer having a volume resistivity .rho.(.OMEGA.m), a dielectric constant .epsilon..sub.r, and a thickness d (m), and being spaced from the workpiece which is attracted thereto by a gap having a distance .delta.(m). The volume resistivity .rho., the dielectric constant .epsilon..sub.r, the thickness d, and the distance .delta. satisfy the following relationship:1.731.times.10.sup.-11 .rho.{.epsilon..sub.r +d/.delta.}<60.

Abstract: An electrostatic chuck for electrostatically attracting and holding an object such as a semiconductor wafer includes a base plate, at least two layers each including an electrically insulating film and an electrode attached to a lower surface thereof, the at least two layers being disposed as attractive layers on the base plate, and a voltage applying assembly for selectively applying a voltage to at least one of the electrodes to electrostatically attract the object to the insulating film of an uppermost one of the layers. The insulating films may have different insulation resistances to allow for a wider range of temperature changes.

Abstract: A first voltage is first applied to the electrode or electrodes of an electrostatic chuck for electrostatically attracting a workpiece such as a silicon wafer. Then, before the workpiece is removed from the electrostatic chuck, a second voltage which is of opposite polarity to the first voltage is applied to the electrostatic chuck for eliminating a residual attractive force from the electrostatic chuck. The second voltage has a voltage value which is 1.5 to 2 times higher than the voltage value of the first voltage. The second voltage is continuously applied for a period of time which is in inverse proportion to the voltage value of the second voltage.

Abstract: A dielectric ceramic for use in an electrostatic chuck, formed by firing in a reducing atmosphere a ceramic material mainly comprised of alumina, wherein said ceramic material comprises an alkaline earth metal in an amount of from 1.0 to 6.0% by weight in terms of oxide and a transition metal in an amount of from 0.5 to 6.0% by weight in terms of oxide, while controlling the dew point of atmosphere gas to be not more than 45.degree. C.Also disclosed is a method of making a dielectric ceramic for use in an electrostatic chuck, comprising firing a ceramic material mainly comprised of alumina and containing from 1.0 to 6.0% by weight of an alkaline earth metal in terms of oxide and from 0.5 to 6.0% by weight of a transition metal in terms of oxide, in a reducing atmosphere while controlling the dew point of atmosphere gas.