Electrostatic chucks and process for producing the same
AssigneeNGK Insulators, Ltd.
InventorHideyoshi Tsuruta
Life of this patent
Estimating the term…
Abstract
An electrostatic chuck including a dielectric layer made of aluminum nitride, an inner electrode buried in the dielectric layer, and a surface layer covering a surface of the dielectric layer. The surface layer is made of a material harder than the aluminum nitride constituting the dielectric layer and having a thickness of not less than 200 nm, and the surface of the dielectric layer has a center-line average surface roughness of not more than 25 nm. The electrostatic chuck is adapted to adsorb a wafer onto the dielectric layer through the surface layer.
Claims16
An electrostatic chuck comprising a dielectric layer made of aluminum nitride, an inner electrode buried in the dielectric layer, and a surface layer covering a surface of the dielectric layer, said surface layer being made of a material harder than the aluminum nitride constituting the dielectric layer and having a thickness of not less than 200 nm, said surface of the dielectric layer having a center-line average surface roughness of not more than 25 nm, and said electrostatic chuck being adapted to adsorb a wafer onto the dielectric layer through the surface layer.
A method for producing an electrostatic chuck adapted to adsorb a wafer onto a dielectric layer made of aluminum nitride, comprising the steps of preparing the dielectric layer made of the aluminum nitride, adjusting a surface of the dielectric layer to a center-line average surface roughness of not less than 25 nm, and covering the surface of the dielectric layer with not less than 200 nm in thickness of a material harder than said aluminum nitride constituting the dielectric layer.
Dependencies are inferred from the claim text.