ALEXANDRIA, Va., July 9 -- United States Patent no. 12,353,121, issued on July 8, was assigned to SHIN-ETSU CHEMICAL Co. LTD. (Tokyo).
"Reflective mask blank, and reflective mask" was invented by Taiga Ogose (Joetsu, Japan) and Takuro Kosaka (Joetsu, Japan).
According to the abstract* released by the U.S. Patent & Trademark Office: "A reflective mask blank including a substrate, a multilayer reflection film formed on one main surface of the substrate and reflects exposure light. The multilayer reflection film has a periodically laminated structure portion in which low refractive index layers and high refractive index layers are alternately laminated, and at least one of the low refractive index layer has a two-layered structure consisting...