Reflective mask blank for EUV lithography, mask blank for EUV lithography, and manufacturing methods thereof

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.