Reflective mask blank, reflective mask, method of manufacturing reflective mask blank, and method of manufacturing reflective mask

A method of manufacturing a reflective mask blank comprising:

• forming 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 on a substrate such that the substrate, the multilayer reflective film, the protection film, and the phase shift film are laminated in an order of the substrate, the multilayer reflective film, the protection film,
• wherein the phase shift film includes an Ir-based material comprising Ir as a main component, the protection film includes a Rh-based material comprising Rh as a main component, the Ir compound includes Ir in an amount of 80 at % or more, and the Ir compound includes Si in an amount of 15 at % or less.