US 12,032,280 B2
Reflective mask blank, reflective mask, and method for manufacturing reflective mask
Hiroshi Hanekawa, Fukushima (JP); Taiga Fudetani, Fukushima (JP); Yusuke Ono, Fukushima (JP); and Shunya Taki, Fukushima (JP)
Assigned to AGC INC., Tokyo (JP)
Filed by AGC INC., Tokyo (JP)
Filed on Dec. 19, 2023, as Appl. No. 18/544,970.
Application 18/544,970 is a continuation of application No. PCT/JP2023/016365, filed on Apr. 25, 2023.
Claims priority of application No. 2022-074386 (JP), filed on Apr. 28, 2022.
Prior Publication US 2024/0160097 A1, May 16, 2024
Int. Cl. G03F 1/24 (2012.01); G03F 1/26 (2012.01)
CPC G03F 1/24 (2013.01) [G03F 1/26 (2013.01)] 18 Claims
 
1. A reflective mask blank comprising:
a substrate;
a multilayer reflective film configured to reflect EUV light;
a protective film; and
a phase shift film configured to shift a phase of EUV light, in this order, wherein
the phase shift film comprises a first layer comprising one or more first elements selected from a group consisting of ruthenium, rhenium, iridium, silver, osmium, gold, palladium, and platinum, and a second layer comprising one or more second elements selected from a group consisting of tantalum and chromium,
the first layer comprises a region A1 in which a content of an element having a highest content among the one or more first elements increases in a thickness direction from a side opposite to the second layer toward the second layer, and the region A1 is present adjacent to the second layer.