Protective coating for electrostatic chucks
An ElectroStatic Chuck (ESC) including a chucking surface having at least a portion covered with a coating of silicon oxide (SiO 2 ), silicon nitride (Si 3 N 4 ) or a combination of both. The coating can be applied in situ a processing chamber of a substrate processing tool and periodically removed and re-applied in situ to create fresh coating.
1. An ElectroStatic Chuck (ESC), comprising a pedestal having a chucking surface arranged to chuck a substrate, wherein the electrostatic chuck is configured to generate electrostatic force at the chucking surface to clamp the substrate, wherein the chucking surface has a multi-layered coating comprising a top layer of silicon oxide and a bottom layer of silicon nitride or vice versa, wherein a material of an entirety or substantial entirety of the top layer is different from a material of an entirety or substantial entirety of the bottom layer, and wherein the multi-layered coating reduces charge traps in the chucking surface, wherein the multi-layered coating has a thickness ranging from 50 nanometers to 30 microns, wherein the ESC is further arranged to operate within a substrate processing chamber maintained at an elevated temperature such that an electrical conductivity of the silicon oxide or silicon nitride is increased to a level where the chucking surface generates sufficient electrostatic force to clamp the substrate.
2. The ESC of claim 1 , wherein the multi-layered coating comprises the top layer of silicon oxide and the bottom layer of silicon nitride.
3. The ESC of claim 1 , wherein the multi-layered coating comprises the top layer of silicon nitride and the bottom layer of silicon oxide.
4. The ESC of claim 1 , wherein the chucking surface on which the multi-layered coating is formed comprises a dielectric over an electrode.
5. The ESC of claim 1 , further arranged to operate, when the substrate is chucked to the chucking surface within a substrate processing chamber, at a temperature ranging from 450 to 600 degrees C.
6. The ESC of claim 1 , wherein the chucking surface with the coating of the silicon oxide or the silicon nitride includes one or more minimum contact areas formed on the chucking surface.
7. The ESC of claim 1 , wherein the ESC is either a Coulombic type ESC or a Johnsen-Rahbek (J-R) type ESC.