DIELECTRIC CERAMICS FOR ELECTROSTATIC CHUCKS AND METHOD OF MAKING THEM

摘要

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. 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 1.0 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.