	US 12,298,660 B2
	Reflective mask blank for EUV lithography, reflective mask for EUV lithography, and method for manufacturing same
Hirotomo Kawahara, Tokyo (JP); Daijiro Akagi, Tokyo (JP); Hiroaki Iwaoka, Tokyo (JP); Toshiyuki Uno, Tokyo (JP); Michinori Suehara, Tokyo (JP); and Keishi Tsukiyama, Tokyo (JP)
Assigned to AGC INC., Tokyo (JP)
Filed by AGC INC., Tokyo (JP)
Filed on Mar. 6, 2024, as Appl. No. 18/596,919.
Application 18/596,919 is a continuation of application No. 18/198,881, filed on May 18, 2023, granted, now 11,953,822.
Application 18/198,881 is a continuation of application No. PCT/JP2022/005224, filed on Feb. 9, 2022.
Claims priority of application No. 2021-022583 (JP), filed on Feb. 16, 2021.
Prior Publication US 2024/0210814 A1, Jun. 27, 2024
Int. Cl. G03F 1/32 (2012.01); G03F 1/24 (2012.01); G03F 1/48 (2012.01)

CPC G03F 1/32 (2013.01) [G03F 1/24 (2013.01); G03F 1/48 (2013.01)]

20 Claims

1. A reflective mask blank for EUV lithography, comprising:

a substrate,

a multilayer reflective film reflecting EUV light, and

a phase shift film shifting a phase of the EUV light,

wherein the substrate, the multilayer reflective film, and the phase shift film are formed in this order,

the phase shift film comprises a layer 1 comprising ruthenium (Ru) and nitrogen (N),

the layer 1 has an absolute value of a film stress of 1,000 MPa or less,

the phase shift film further comprises a layer 2 comprising at least one element (X) selected from the group consisting of chromium (Cr), tantalum (Ta), titanium (Ti), rhenium (Re), tungsten (W), bismuth (Bi), manganese (Mn), platinum (Pt), copper (Cu), iridium (Ir), and vanadium (V), and

a surface roughness (rms) of a surface of the phase shift film is 0.50 nm or less.