US 11,914,284 B2
Reflective mask blank, reflective mask, method of manufacturing reflective mask blank, and method of manufacturing reflective mask
Daijiro Akagi, Tokyo (JP); Shunya Taki, Fukushima (JP); Takuma Kato, Tokyo (JP); Ichiro Ishikawa, Tokyo (JP); and Kenichi Sasaki, Tokyo (JP)
Assigned to AGC Inc., Tokyo (JP)
Filed by AGC Inc., Tokyo (JP)
Filed on Jul. 3, 2023, as Appl. No. 18/346,563.
Application 18/346,563 is a continuation of application No. PCT/JP2022/044842, filed on Dec. 6, 2022.
Claims priority of application No. 2021-201671 (JP), filed on Dec. 13, 2021; and application No. 2022-108641 (JP), filed on Jul. 5, 2022.
Prior Publication US 2023/0350285 A1, Nov. 2, 2023
Int. Cl. G03F 1/24 (2012.01); G03F 1/32 (2012.01); G03F 1/48 (2012.01); G03F 1/80 (2012.01)
CPC G03F 1/24 (2013.01) [G03F 1/32 (2013.01); G03F 1/48 (2013.01); G03F 1/80 (2013.01)] 16 Claims
 
1. A reflective mask blank comprising:
a substrate;
a multilayer reflective film that reflects EUV light;
a protection film that protects the multilayer reflective film; and
a phase shift film that shifts a phase of the EUV light, the substrate, the multilayer reflective film, the protection film, and the phase shift film being arranged in this order, wherein
the phase shift film contains at least one first element X1 selected from the first group consisting of ruthenium (Ru), and gold (Au), and at least one second element X2 selected from the second group consisting of oxygen (O), boron (B), and carbon (C),
in the phase shift film, a chemical shift of a peak of 3d5/2 or a peak of 4f7/2 of the first element X1 observed by X-ray electron spectroscopy is less than 0.3 eV, and
the phase shift film contains 1 at % or more and 55 at % or less of oxygen (O).