US 12,346,018 B2
Reflective mask blank, reflective mask, method of manufacturing reflective mask blank, and method of manufacturing reflective mask
Yuya Nagata, Tokyo (JP); Daijiro Akagi, Tokyo (JP); Kenichi Sasaki, Tokyo (JP); and Hiroaki Iwaoka, Tokyo (JP)
Assigned to AGC Inc., Tokyo (JP)
Filed by AGC Inc., Tokyo (JP)
Filed on Apr. 29, 2024, as Appl. No. 18/649,410.
Application 18/649,410 is a continuation of application No. 18/517,796, filed on Nov. 22, 2023, granted, now 12,001,134.
Application 18/517,796 is a continuation of application No. PCT/JP2023/023323, filed on Jun. 23, 2023.
Claims priority of application No. 2022-108642 (JP), filed on Jul. 5, 2022; and application No. 2022-179622 (JP), filed on Nov. 9, 2022.
Prior Publication US 2024/0295807 A1, Sep. 5, 2024
Int. Cl. G03F 1/24 (2012.01); G03F 1/26 (2012.01); G03F 1/52 (2012.01); G03F 1/80 (2012.01)
CPC G03F 1/24 (2013.01) [G03F 1/26 (2013.01); G03F 1/52 (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;
a protection film that protects the multilayer reflective film; and
a phase shift film that shifts a phase of the EUV light, in this order,
wherein the phase shift film contains Ir as a main component;
a ratio (Ip/Ia) of a maximum value Ip of an intensity of a peak in a range of 2θ of 35 degrees to 45 degrees to an average value Ia of an intensity in a range of 2θ of 55 degrees to 60 degrees by an XRD method with a CuKα ray is 1.0 or more and 30 or less;
a refractive index n of the phase shift film to the EUV light is 0.925 or less;
an extinction coefficient k of the phase shift film to the EUV light is 0.030 or more; and
the phase shift film contains 50 at % or more of Ir, contains O and N, and contains at least one second element X2 selected from a second group consisting of Ta, Cr, Mo, W, Re, and Si.