Reflective mask blank for EUV lithography, or reflective layer-coated substrate for EUV lithography, and process for its production

摘要

To provide a process for producing an EUV mask blank, whereby mixing at each interface between layers constituting a Mo/Si multilayer reflective film during a step involving heating, is suppressed, and a process for producing a reflective layer-coated substrate to be used for the production of the EUV mask blank. A process for producing a reflective layer-coated substrate for EUV lithography (EUVL), which has a step of forming a Mo/Si multilayer reflective film by alternately forming a molybdenum (Mo) layer and a silicon (Si) layer on a film-forming surface of a substrate, wherein after forming each Si layer except for a Si layer as the uppermost layer among Si layers constituting the Mo/Si multilayer reflective film, the surface of such each Si layer is exposed to a nitrogen-containing atmosphere held in a plasma state without being exposed to the air atmosphere, and then, a Mo layer is formed.

主权项

1. A process for producing a reflective layer-coated substrate for EUV lithography, comprising:
forming on a substrate a Mo/Si multilayer reflective film comprising a plurality of Mo layers and a plurality of Si layers such that the Mo layers and the Si layers are alternately stacked on a film-forming surface of the substrate, wherein the forming of the Mo/Si multilayer reflective film comprises exposing a surface of each of the Si layers to a nitrogen-containing atmosphere held in a plasma state without being exposed to an air atmosphere such that the Mo/Si multilayer reflective film has a plurality of thin films formed between the Si layers and the Mo layers, respectively, and that each of the thin films includes nitrogen in an amount of from 0.5 to 25 at % and Si in an amount of from 75 to 99.5 at % and has a film thickness in a range of from 0.2 nm to 2.0 nm.