ALEXANDRIA, Va., June 16 -- United States Patent no. 12,308,220, issued on May 20, was assigned to NGK INSULATORS Ltd. (Nagoya, Japan).
"Wafer placement table" was invented by Tatsuya Kuno (Nagoya, Japan) and Seiya Inoue (Handa, Japan).
According to the abstract* released by the U.S. Patent & Trademark Office: "A wafer placement table includes a ceramic plate having a wafer placement surface and an electrode, a cooling plate made of a metal-ceramic composite and having a cooling medium passage, and a joining layer configured to join the plates. A distance from the wafer placement surface to at least one of upper base or lower base of the cooling medium passage is not constant. The cooling plate has a plurality of plate portions including ...