The object of the present invention is to provide an electrostatic chuck
in which the surface can be kept smooth after being exposed to plasma, so
as to protect a material to be clamped such as a silicon wafer from being
contaminated with particles, and which is excellent in clamping and
releasing a material to be clamped. According to the present invention,
there is provided an electrostatic chuck comprising a dielectric material
in which alumina is 99.4 wt % or more, titanium oxide is more than 0.2 wt
% and equal to or less than 0.6 wt %, whose average particle diameter is
2 .mu.m or less, and whose volume resistivity is 10.sup.8-10.sup.11
.OMEGA.cm in room temperature, wherein the electrostatic chuck is used in
a low temperature of 100.degree. C or less.