US Patent Issued to SHIN-ETSU CHEMICAL on Jan. 27 for "Photomask blank, manufacturing method of photomask and photomask" (Japanese Inventor)

ALEXANDRIA, Va., Jan. 28 -- United States Patent no. 12,535,728, issued on Jan. 27, was assigned to SHIN-ETSU CHEMICAL Co. LTD. (Tokyo).

"Photomask blank, manufacturing method of photomask and photomask" was invented by Naoki Matsuhashi (Niigata, Japan).

According to the abstract* released by the U.S. Patent & Trademark Office: "A photomask blank having a substrate; and a multilayer film including a first layer, a second layer, and a third layer. The first layer contains 43 at % or less chromium, 32 at % or more oxygen, 25 at % or less nitrogen and 5 at % or more and 18 at % or less carbon and has a thickness of 8 nm or more and 16 nm or less. The second layer contains 66 at % or more and 92 at % or less chromium and 8 at % or more and 30...