Phase-shift photomask-blank, phase-shift photomask and fabrication method thereof

摘要

On a substrate (1) that is transparent to exposure light, a phase-shift multilayer film (2) including a stack of two layers of a metal silicide compound (2a, 2b) is formed. A stabilized oxide layer (2c) is formed on the surface of the metal silicide compound layer (2b) close to the top surface. The layer (2a) close to the substrate (the lower layer) of the phase-shift multilayer film (2) is made of a relatively-metal-rich metal silicide compound, and the upper layer (2b) is made of a relatively-metal-poor metal silicide compound. The stabilized oxide layer (2c) has a metal-poor composition, and the metal content thereof is equal to or less than one third of the metal content of the lower layer (2a). Thus, the stabilized oxide layer (2c) is highly chemically stable and has a high chemical resistance.