Abstract Proposed is a ceramic-made electrostatic chuck consisting of two insulating ceramic layers and a metallic electrode layer integrally sandwiched between the two insulating layers, which has a very quick response characteristic to turning-on and -off of the electric voltage applied to the electrodes without affecting the very high electrostatic attracting force. This improvement can be obtained by forming the insulating ceramic layers from a specific ceramic material consisting of a highly resistive ceramic material such as alumina and the like and titanium nitride admixed with the former in an amount not exceeding 5% by weight but sufficient to impart the insulating ceramic layers with a volume resistivity in the range from 1×10 8 to 1×10 13 ohm.cm at 20° C.
A ceramic electrostatic chuck which comprises: two insulating layers made from a ceramic material and an electrode layer made from a metal and integrally sandwiched between the insulating layers; the ceramic material consisting of a mixture of a resistive ceramic material having a volume resistivity of at least 1×10 14 ohm.cm at 20° C. and means to provide the ceramic material of the insulating layers with a volume resistivity in the range from 1×10 8 to 1×10 13 ohm.cm at 20° C., said means being titanium nitride, the amount of titanium nitride not exceeding 5% by weight based on the amount of the resistive ceramic material.
Claim 2
Dependent Claim
106 words
A ceramic electrostatic chuck which comprises: two insulating layers made from a ceramic material and an electrode layer made from a metal and integrally sandwiched between the insulating layers; the ceramic material consisting of a mixture of a resistive ceramic material having a volume resistivity of at least 1×10 14 ohm.cm at 20° C. and means to provide the ceramic material of the insulating layers with a volume resistivity in the range from 1×10 8 to 1×10 13 ohm.cm at 20° C., said means being titanium nitride, the amount of titanium nitride not exceeding 5% by weight based on the amount of the resistive ceramic material.
Claim 3
Dependent Claim
33 words
The ceramic electrostatic chuck as claimed in claim 1 in which the resistive ceramic material is selected from the group consisting of aluminum oxide, aluminum nitride, zirconium oxide, silicon dioxide, and boron nitride.
Claim 4
Dependent Claim
47 words
The ceramic electrostatic chuck as claimed in claim 1 in which one of the two insulating layers has a thickness in the range from 0.3 to 1.0 mm and the other of the two insulating layers has a thickness in the range from 0.5 to 25 mm.