A
photomask blank comprising a multilayer film including at least four
layers of different compositions, wherein the interface between the
layers is moderately graded in composition; a
phase shift mask blank comprising a phase shift film of at least two
layers including a
surface layer of a composition based on a
zirconium silicide compound and a substrate adjacent layer of a composition based on a
molybdenum silicide compound, and a further layer between one layer and another layer of a different composition, the further layer having a composition moderately graded from that of the one layer to that of the other layer; a
phase shift mask blank comprising a phase shift film including a plurality of layers containing a
metal and
silicon in different compositional ratios which are stacked in such order that a layer having a higher
etching rate is on the substrate side and a layer having a lower
etching rate is on the surface side. The invention provides a
photomask blank, typically a
phase shift mask blank, which satisfies optical properties such as
transmittance, reflectance and
refractive index at an
exposure wavelength of interest, and has an etched pattern with a minimal
line edge roughness, and a
photomask, typically a phase shift
mask obtained therefrom.