US 12,001,134 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 Nov. 22, 2023, as Appl. No. 18/517,796.
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 2024/0094622 A1, Mar. 21, 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)] 19 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/la) 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, and
an extinction coefficient k of the phase shift film to the EUV light is 0.030 or more,
the phase shift film contains 50 at % or more of Ir and a first element X1 selected from the group consisting of O, B, C, and N, and O content being 15 at % or less, and
when a grayscale image is obtained by imaging a cross section of the phase shift film with a scanning transmission electron microscope (STEM) and a brightness profile of the grayscale image is created, skewness (Rsk) of the brightness profile is negative.