Patent ID: 11914284
Assignee: AGC INC.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 14:
15. A method of manufacturing a reflective mask blank comprising:
forming a multilayer reflective film on a substrate, the multilayer reflective film reflecting EUV light;
forming a protection film on the multilayer reflective film, the protection film protecting the multilayer reflective film; and
forming a phase shift film on the protection film, the phase shift film shifting a phase of the EUV light on the protection film, wherein
the phase shift film contains at least one first element X1 selected from the first group consisting of ruthenium (Ru), iridium (Ir), platinum (Pt), palladium (Pd), and gold (Au), and at least one second element X2 selected from the second group consisting of oxygen (O), boron (B), and carbon (C),
in the phase shift film, a chemical shift of a peak of 3d5/2 or a peak of 4f7/2 of the first element X1 observed by X-ray electron spectroscopy is less than 0.3 eV, and
the phase shift film contains 1 at % or more and 55 at % or less of oxygen (O).