US Patent Issued to S&S TECH on June 23 for "Phase shift blankmask and photomask for EUV lithography" (South Korean Inventors)

ALEXANDRIA, Va., July 15 -- United States Patent no. 12,663,707, issued on June 23, was assigned to S&S TECH Co. Ltd. (Daegu-si, South Korea).

"Phase shift blankmask and photomask for EUV lithography" was invented by Yong-Dae Kim (Daegu, South Korea), Chul-Kyu Yang (Daegu-si, South Korea) and Mi-Kyung Woo (Daegu-si, South Korea).

According to the abstract* released by the U.S. Patent & Trademark Office: "Disclosed is a blankmask for EUV lithography, including a reflective film, a capping film, an etch stop film, a phase shift film, and a hard mask film which are sequentially formed on a substrate. The phase shift film contains ruthenium (Ru), and the etch stop film contains chrome (Cr) and niobium (Nb). In the etch stop film, the content ...