Wafer placement table
A wafer placement table includes a ceramic base, a cooling base, and a bonding layer. The ceramic base includes an outer peripheral part having an annular focus ring placement surface on an outer peripheral side of a central part having a circular wafer placement surface. The cooling base contains metal. The bonding layer bonds the ceramic base with the cooling base. The outer peripheral part of the ceramic base has a thickness of less than or equal to 1 mm and does not incorporate an electrode.
1 . A wafer placement table comprising:
a ceramic base that includes an outer peripheral part having an annular focus ring placement surface on an outer peripheral side of a central part having a circular wafer placement surface;
a cooling base containing metal; and
a bonding layer that bonds the ceramic base with the cooling base, wherein
the outer peripheral part of the ceramic base has a thickness of less than or equal to 0.7 mm and does not incorporate an electrode; and
wherein the bonding layer is a metal bonding layer;
wherein parts exposed on a side surface of an outer peripheral part of the ceramic base, a periphery of the metal bonding layer, a side surface of the cooling base, and a top surface of the cooling base are coated with an electrically insulating film; and
wherein a difference in coefficient of thermal expansion between the ceramic base and the cooling base is lower than or equal to 1×10 −6 /K.
2 . The wafer placement table according to claim 1 , wherein
the cooling base is connected to at least a focus ring attracting power supply, a bias radio-frequency power supply, and a source radio-frequency power supply.
3 . The wafer placement table according to claim 1 , wherein
the central part of the ceramic base is thicker than the outer peripheral part, incorporates a wafer attracting electrode, and incorporates a radio-frequency electrode between the wafer attracting electrode and a surface on a side opposite to the wafer placement surface,
the radio-frequency electrode is connected to the cooling base, and
the wafer attracting electrode is connected to a wafer attracting power supply without being connected to the cooling base.
4 . The wafer placement table according to claim 1 , wherein
the central part of the ceramic base is thicker than the outer peripheral part, incorporates a wafer attracting electrode, and does not incorporate a radio-frequency electrode between the wafer attracting electrode and a surface on a side opposite to the wafer placement surface, and
the wafer attracting electrode is connected to a wafer attracting power supply without being connected to the cooling base.
5 . The wafer placement table according to claim 1 , wherein
the central part of the ceramic base is thicker than the outer peripheral part, incorporates a wafer attracting electrode, and does not incorporate a radio-frequency electrode between the wafer attracting electrode and a surface on a side opposite to the wafer placement surface,
the wafer attracting electrode is connected to the cooling base, and
the cooling base is connected to a wafer attracting power supply.
6 . The wafer placement table according to claim 1 , wherein
the central part of the ceramic base has the same thickness as the outer peripheral part of the ceramic base and does not incorporate an electrode, and
the cooling base is connected to a wafer attracting power supply.
7 . The wafer placement table according to claim 1 , wherein
the cooling base does not have a through-hole for supplying electric power.
8 . The wafer placement table according to claim 1 , wherein
the outer peripheral part of the ceramic base has a thickness of less than or equal to 0.5 mm.