Dielectric ceramics for electrostatic chucks and method of making them
First Claim
1. A dielectric ceramic material for use in an electrostatic chuck, formed by firing in a reducing atmosphere, while controlling the dew point of atmosphere gas, said dielectric ceramic material comprising alumina, 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, wherein said dielectric ceramic material has an insulation resistance of not more than 1012 Ω
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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° 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.
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Citations
6 Claims
- 1. A dielectric ceramic material for use in an electrostatic chuck, formed by firing in a reducing atmosphere, while controlling the dew point of atmosphere gas, said dielectric ceramic material comprising alumina, 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, wherein said dielectric ceramic material has an insulation resistance of not more than 1012 Ω
- 4. A dielectric ceramic material for an electrostatic chuck, formed by firing in a reducing atmosphere while controlling the dew point of the atmosphere gas, said dielectric ceramic material comprising a sintering aid, alumina, 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, wherein said dielectric ceramic material has an insulation resistance of not more than 1012 Ω
Specification