US 12,222,640 B2
Reflective mask blank, reflective mask, method of manufacturing reflective mask blank, and method of manufacturing reflective mask
Shunya Taki, Tokyo (JP); Hiroaki Iwaoka, Tokyo (JP); Daijiro Akagi, Tokyo (JP); and Ichiro Ishikawa, Tokyo (JP)
Assigned to AGC Inc., Tokyo (JP)
Filed by AGC Inc., Tokyo (JP)
Filed on Oct. 20, 2023, as Appl. No. 18/382,269.
Application 18/382,269 is a continuation of application No. 18/193,674, filed on Mar. 31, 2023, granted, now 11,829,065.
Application 18/193,674 is a continuation of application No. PCT/JP2022/030631, filed on Aug. 10, 2022.
Claims priority of application No. 2021-138856 (JP), filed on Aug. 27, 2021.
Prior Publication US 2024/0168370 A1, May 23, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. G03F 1/26 (2012.01); G03F 1/24 (2012.01); G03F 1/48 (2012.01); G03F 1/80 (2012.01)
CPC G03F 1/26 (2013.01) [G03F 1/24 (2013.01); G03F 1/48 (2013.01); G03F 1/80 (2013.01)] 18 Claims
 
1. A reflective mask blank comprising:
a substrate;
a multilayer reflective film that reflects EUV light; and
a phase shift film that shifts a phase of the EUV light, the substrate, the multilayer reflective film, and the phase shift film being arranged in this order, wherein
the phase shift film contains a compound containing Ru and Cr,
an element ratio between Cr and Ru (Cr:Ru) in the phase shift film is 5:95 to 42:58, and
a melting point MP1 of an oxide of the compound and a melting point MP2 of a fluoride or an oxyfluoride of the compound satisfy the following relation (1):
0.625MP1+MP2≤1000  (1).