Mask blank, phase shift mask, and method of manufacturing semiconductor device

A phase shift mask, comprising:

• a transparent substrate;
• an etching stopper film provided on the transparent substrate;
• and
• a phase shift film provided on the etching stopper film, containing silicon and oxygen, and having a phase shift pattern,
• wherein a refractive index n1 of the phase shift film for light of 193 nm wavelength is 1.5 or more and an extinction coefficient k1 of the phase shift film for light of 193 nm wavelength is 0.1 or less, and
• wherein a refractive index n2 of the etching stopper film for light of 193 nm wavelength is 2.6 or more and an extinction coefficient k2 of the etching stopper film for light of 193 nm wavelength is 0.4 or less, and
• wherein the refractive index n2 and the extinction coefficient k2 of the etching stopper film satisfy at least one of the following two conditions:
• k2≤[(−0.188×n2)+0.879];
• (Condition 1)
• k2≤[(2.750×n2)−6.945]. (Condition 2)