ALEXANDRIA, Va., March 12 -- United States Patent no. 12,249,492, issued on March 11, was assigned to Sumitomo Osaka Cement Co. Ltd. (Tokyo).
"Electrostatic chuck device" was invented by Masaki Hirayama (Tokyo) and Tetsuro Itagaki (Tokyo).
According to the abstract* released by the U.S. Patent & Trademark Office: "An electrostatic chuck device includes: an electrostatic chuck plate having a dielectric substrate having a placement surface on which a wafer is placed and an adsorption electrode positioned in the dielectric substrate; a metal base supporting the electrostatic chuck plate from a back surface side opposite to the placement surface; and a focus ring installed on an outer peripheral portion of the electrostatic chuck plate and su...