Reflective mask blank and method for manufacturing the same

A method for manufacturing a reflective mask blank, comprising at least steps of:

• forming a multilayer reflective film on a substrate, the multilayer reflective film reflecting exposure light;
• and
• forming an absorber film on the multilayer reflective film, the absorber film absorbing the exposure light, wherein
• the method further comprises a step of forming a reference mark on a surface on a same side as the multilayer reflective film of the reflective mask blank, the reference mark consisting of a main mark serving as a reference position for a defect position, and an auxiliary mark group disposed around the main mark,
• when forming the auxiliary mark group of the reference mark, a plurality of auxiliary marks are all formed in a same shape and in a same orientation at intervals from one another to extend in at least one direction starting from the main mark, by an indentation method with a micro-indenter, and thereby the auxiliary mark group consisting of the plurality of auxiliary marks is formed.