Yttria-zirconia sintered ceramics for plasma resistant materials
Disclosed is a ceramic sintered body comprising yttrium oxide and zirconium oxide wherein the ceramic sintered body comprises not less than 75 mol % to not greater than 95 mol % yttrium oxide and not less than 5 mol % to not greater than 25 mol % zirconium oxide, wherein the ceramic sintered body comprises porosity in an amount of less than 2% by volume, wherein a density of the ceramic sintered body does not vary by more than 2% relative to theoretical density across a greatest dimension. The ceramic sintered body has a grain size of from 0.4 to less than 2 um as measured according to ASTM E1 12-2010. The ceramic sintered body may be machined into plasma resistant components for use in plasma processing chambers. Methods of making are also disclosed.
1 . A ceramic sintered body comprising:
yttrium oxide and zirconium oxide, wherein the ceramic sintered body comprises not less than 75 mol % to not greater than 95 mol % yttrium oxide and not less than 5 mol % to not greater than 25 mol % zirconium oxide, wherein the ceramic sintered body comprises porosity in an amount of less than 2% by volume, wherein a density of the ceramic sintered body does not vary by more than 2% relative to theoretical density across a greatest dimension, and wherein the ceramic sintered body has an average grain size of from 0.4 to less than 2 μm as measured according to ASTM E1 12-2010.
2 . The ceramic sintered body of claim 1 having at least one surface comprising yttrium oxide and zirconium oxide wherein the at least one surface is polished and comprises porosity in an amount of less than 2% by pore area of the at least one surface.
3 . The ceramic sintered body of claim 2 wherein porosity as measured on a polished surface extends throughout the ceramic sintered body.
4 . The ceramic sintered body of claim 1 having a pore diameter of not less than 0.1 to not greater than 3 μm as measured across a polished surface.
5 . The ceramic sintered body of claim 1 having at least one surface with an average grain size of from 0.75 μm to 6 μm as measured according to ASTM E1 12-2010.
6 . The ceramic sintered body of claim 1 comprising a c-type cubic solid solution phase.
7 . The ceramic sintered body of claim 1 having the greatest dimension of from 100 mm to 622 mm with regard to the longest extension of the sintered body.
8 . A method of making a ceramic sintered body according to claim 1 , the method comprising the steps of:
a. combining powders of yttrium oxide and zirconium oxide to make a powder mixture;
b. calcining the powder mixture by applying heat to raise the temperature of the powder mixture to a calcination temperature and maintaining the calcination temperature to form a calcined powder mixture;
c. disposing the calcined powder mixture inside a volume defined by an electrically conductive tool set of a sintering apparatus and creating vacuum conditions inside the volume;
d. applying pressure to the calcined powder mixture while employing a direct current to heat the electrically conductive tool set to a sintering temperature and performing sintering to form the ceramic sintered body; and
e. lowering the temperature of the ceramic sintered body.
9 . The method according to claim 8 further comprising the steps of:
f. optionally annealing the ceramic sintered body by applying heat to raise the temperature of the ceramic sintered body to reach an annealing temperature to form an annealed ceramic sintered body; and
g. lowering the temperature of the annealed ceramic sintered body.
10 . The method according to claim 8 further comprising the step of:
h. optionally machining the ceramic sintered body to form a ceramic sintered body component such as a window, an RF window, a lid, a focus ring, a shield ring, a nozzle, a gas injector, a shower head, a gas distribution plate, a chamber liner, a chuck, an electrostatic chuck, a puck, and/or a cover ring in plasma processing chambers.
11 . The method according to claim 8 wherein the calcined powder mixture has a purity of 99.99% and higher relative to 100% purity as measured using ICP-MS methods.
12 . The method according to claim 8 wherein the calcined powder mixture has a specific surface area (SSA) of from 2 to 14 m 2 /g as measured according to ASTM C1274.
13 . The method according to claim 8 wherein the calcination temperature is from 600° C. to 1200° C.
14 . The method according to claim 8 wherein the pressure is from 10 to 60 MPa.
15 . The method according to claim 8 wherein the sintering temperature is from 1200° C. to 1700° C.