Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
66 words
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.
Claim 2
Dependent Claim
66 words
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.
Claim 3
Dependent Claim
19 words
The dielectric ceramic for use in an electrostatic chuck according to Claim 1, wherein said transition metal comprises titanium.
Claim 4
Dependent Claim
28 words
The dielectric ceramic for use in an electrostatic chuck according to Claim 1, wherein said alkaline earth metal is at least one of Ca, Mg, Sr and Ba.
Claim 5
Independent Claim
68 words
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.
Claim 6
Independent Claim
68 words
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.
Claim 7
Dependent Claim
23 words
The method of making a dielectric ceramic for use in an electrostatic chuck according to Claim 4, wherein said transition metal comprises titanium.
Claim 8
Dependent Claim
44 words
The method of making a dielectric ceramic for use in an electrostatic chuck according to Claim 4, wherein said firing is divided into preliminary firing and main firing, and the preliminary firing is carried out in an atmosphere with a dew point of 45°C.
Claim 9
Dependent Claim
32 words
The method of making a dielectric ceramic for use in an electrostatic chuck according to Claim 4, wherein said dew point of atmosphere gas is controlled to be not more than 45°C.