US 12,216,397 B2
Reflective mask blank for EUV lithography, mask blank for EUV lithography, and manufacturing methods thereof
Daijiro Akagi, Tokyo (JP); Hirotomo Kawahara, Tokyo (JP); Toshiyuki Uno, 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 Oct. 17, 2023, as Appl. No. 18/380,956.
Application 18/380,956 is a continuation of application No. 17/382,755, filed on Jul. 22, 2021, granted, now 11,822,229.
Claims priority of application No. 2020-127311 (JP), filed on Jul. 28, 2020.
Prior Publication US 2024/0045319 A1, Feb. 8, 2024
Int. Cl. H01L 21/033 (2006.01); G03F 1/24 (2012.01); G03F 1/32 (2012.01); H01L 21/02 (2006.01)
CPC G03F 1/24 (2013.01) [G03F 1/32 (2013.01); H01L 21/0332 (2013.01); H01L 21/0337 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A reflective mask blank for EUV lithography, comprising:
a substrate;
a multilayer reflective film for reflecting EUV light; and
a phase shift film for shifting a phase of EUV light, the multilayer reflective film and the phase shift film formed on or above the substrate in this order, wherein
the multilayer reflective film is a Si/Mo multilayer reflective film;
the phase shift film comprises a layer 1 comprising ruthenium (Ru) and at least one selected from the group consisting of oxygen (O) and nitrogen (N);
the layer 1 further comprises at least one element (X1) selected from the group consisting of chromium (Cr) and tantalum (Ta) present in a range of 20:1 to 1:5 in terms of an atomic composition ratio (at %) (Ru:X1) of Ru to X1; and
among diffraction peaks derived from the phase shift film observed at 2θ: from 20° to 50° by out-of-plane XRD method, a peak having the highest intensity has a half value width FWHM of 1.0° or more.
 
19. A method for manufacturing a reflective mask blank for EUV lithography, the method comprising:
forming, on a substrate, a multilayer reflective film for reflecting EUV light; forming, on the multilayer reflective film, a phase shift film for shifting a phase of EUV light, and
forming an etching mask film on the phase shift film; wherein
the multilayer reflective film is a Si/Mo multilayer reflective film
the phase shift film comprises a layer 1 comprising ruthenium (Ru) and at least one selected from the group consisting of oxygen (O) and nitrogen (N);
the layer 1 further comprises at least one element (X1) selected from the group consisting of chromium (Cr) and tantalum (Ta) present in a range of 20:1 to 1:5 in terms of an atomic composition ratio (at %) (Ru:X1) of Ru to X1;
among diffraction peaks derived from the phase shift film observed at 2θ: from 20° to 50° by out-of-plane XRD method, a peak having a highest intensity has a half value width FWHM of 1.0° or more; and
the etching mask film is removable by cleaning with an acid or a base.