Provided is a phase-shift blankmask in which a phase-shift layer is formed in at least two continuous layers or a multi-layer film and an uppermost phase-shift layer included in the phase-shift layer is thinly formed to contain a small amount of oxygen (O) so as to enhance chemical resistance and durability thereof.Accordingly, a phase-shift blankmask including the phase-shift layer having enhanced chemical resistance and durability with respect to a cleaning solution containing acid and basic materials, hot deionized water, or ozone water, which is used in a cleaning process that is repeatedly performed during manufacture of a photomask, may be provided using the uppermost phase-shift layer having the enhanced chemical resistance and durability.Furthermore, degradation in the refractive index and degree of phase shift of the phase-shift layer, caused when the cleaning process is repeatedly performed may be prevented due to the uppermost phase-shift layer having the enhanced chemical resistance and durability. Accordingly, a phase-shift blankmask including a thin phase-shift layer can be provided.