Patent attributes
An electrostatic chuck includes: an electrically-conductive base plate including a first part, a second part at an outer circumference of the first part, and a gas inlet path for introducing a cooling gas; a first electrostatic chuck part configured to clamp a wafer on the first part, including a ceramic dielectric substrate that includes an embedded first clamping electrode and at least one through-hole communicating with the gas inlet path; and a second electrostatic chuck part configured to clamp a focus ring on the second part, including a ceramic layer that includes at least one through-hole for introducing a cooling gas and that includes at least a first layer contacting the focus ring when the second electrostatic chuck part clamps the focus ring, in which the first layer is less dense than the ceramic dielectric substrate. Thereby, the electrostatic chuck can increase the device yield.
