PLASMA RESISTANT YTTRIUM ALUMINUM OXIDE CHAMBER COMPONENTS

1 - 60 . (canceled)

61 . A process ring for use in a plasma vacuum processing chamber, the process ring comprising:

an annular body comprising

at least one first layer comprising a surface having a surface area and at least one crystalline phase of from 90% to 99.8% by volume of polycrystalline yttrium aluminum garnet (YAG),

at least one second layer comprising alumina and zirconia wherein the zirconia comprises at least one of stabilized and partially stabilized zirconia, and

optionally, at least one third layer comprising at least one selected from the group consisting of YAG, alumina, and zirconia,

wherein the at least one second layer is disposed between the at least one first layer and the at least one third layer,

wherein an absolute value of the difference in coefficient of thermal expansion (CTE) between the at least one first, second and third layers is from 0 to 0.75×10 −6 /° C. as measured in accordance with ASTM E228-17, and

wherein the at least one first, second and third layers form a unitary sintered ceramic body; and

an opening surrounded by the annular body, wherein the surface comprises pores having a pore size not exceeding 5 μm and having a maximum pore size of 1.5 μm for at least 95% of the pores,

wherein the pores occupy less than 0.2% of the surface area.

62 . The process ring of claim 61 wherein the polycrystalline yttrium aluminum garnet comprises pores having a pore size not exceeding 1.75 μm for at least 97% or more of all pores.

63 . The process ring of claim 61 wherein the at least one polycrystalline yttrium aluminum garnet has a maximum pore size not exceeding 2 μm for at least 99% or more of all pores.

64 . The process ring according to claim 61 wherein the polycrystalline yttrium aluminum garnet has a volumetric porosity of from 0.1 to 3%.

65 . The process ring according to claim 61 -wherein the pores occupy less than 0.15% of the surface area.

66 . The process ring according to claim 61 wherein the pores occupy less than 0.10% of the surface area.

67 . A showerhead assembly of a plasma vacuum processing chamber, the showerhead assembly comprising:

a. a backplate portion comprising at least one gas inlet;

b. a frontplate portion opposite the backplate portion, wherein the frontplate portion comprises a plurality of gas distribution holes; and

c. an inner volume in communication with the gas distribution holes and the gas inlet,

wherein the backplate portion and the frontplate portion each comprise at least one first layer comprising a surface having a surface area and at least one crystalline phase of from 90% to 99.8% by volume of polycrystalline yttrium aluminum garnet (YAG),

at least one second layer comprising alumina and zirconia wherein the zirconia comprises at least one of stabilized and partially stabilized zirconia, and

optionally, at least one third layer comprising at least one selected from the group consisting of YAG, alumina, and zirconia, wherein the at least one second layer is disposed between the at least one first layer and the at least one third layer,

wherein an absolute value of the difference in coefficient of thermal expansion (CTE) between the at least one first, second and third layers is from 0 to 0.75×10 −6 /° C. as measured in accordance with ASTM E228-17,

wherein the at least one first, second and third layers form a unitary sintered ceramic body, and wherein the polycrystalline yttrium aluminum garnet comprises pores on the surface wherein the pores have a pore size not exceeding 5 μm and have a maximum pore size of 1.5 μm for at least 95% of the pores,

wherein the pores occupy less than 0.2% of the surface area.

68 . The showerhead assembly according to claim 67 wherein the polycrystalline yttrium aluminum garnet has a volumetric porosity of from 0.1 to 3%.

69 . The showerhead assembly according to claim 68 wherein the polycrystalline yttrium aluminum garnet (YAG) is present in an amount of from 90 to 99.8% by volume.

70 . The showerhead assembly according to claim 67 wherein the polycrystalline yttrium aluminum garnet is present in an amount of from 93 to 99.8% by volume.

71 . The showerhead assembly according to claim 67 wherein the polycrystalline yttrium aluminum garnet has a purity of 99.995% or higher as measured using ICPMS.

72 . The showerhead assembly according to claim 67 wherein the pores occupy less than 0.15% of the surface area.

73 . The showerhead assembly according to claim 67 wherein the pores occupy less than 0.10% of the surface area.

74 . A dielectric window for use in a plasma vacuum processing chamber, the dielectric window comprising:

a body comprising at least one first layer comprising a surface having a surface area and at least one crystalline phase of from 90% to 99.8% by volume of polycrystalline yttrium aluminum garnet (YAG),

at least one second layer comprising alumina and zirconia wherein the zirconia comprises at least one of stabilized and partially stabilized zirconia, and

optionally, at least one third layer comprising at least one selected from the group consisting of YAG, alumina, and zirconia,

wherein the at least one second layer is disposed between the at least one first layer and the at least one third layer,

wherein an absolute value of the difference in coefficient of thermal expansion (CTE) between the at least one first, second and third layers is from 0 to 0.75×10 −6 /° C. as measured in accordance with ASTM E228-17,

wherein the at least one first, second and third layers form a unitary sintered ceramic body, and wherein the polycrystalline yttrium aluminum garnet comprises pores on the surface wherein the pores occupy less than 0.2% of the surface area.

75 . The dielectric window of claim 74 wherein the polycrystalline yttrium aluminum garnet comprises pores having a pore size not exceeding 1.75 iim for at least 97% or more of all pores.

76 . The dielectric window of claim 74 wherein the at least one polycrystalline yttrium aluminum garnet has a maximum pore size not exceeding 2 μm for at least 99% or more of all pores.

77 . The dielectric window according to claim 74 wherein the polycrystalline yttrium aluminum garnet has a volumetric porosity of from 0.1 to 3%.

78 . The dielectric window according to claim 77 wherein the volumetric porosity is from 0.1 to 2%.

79 . The dielectric window according to claim 74 wherein the pores occupy less than 0.15% of the surface area.

80 . The dielectric window according to claim 74 wherein the pores occupy less than 0.10% of the surface area.