Phase shift mask blank and method for manufacturing phase shift mask

A phase shift mask blank comprising:

• a transparent substrate;
• a phase shift film provided on the transparent substrate, and formed of a material containing silicon (Si) and free of carbon (C);
• and
• a light shielding film provided on a side of the phase shift film away from the transparent substrate, and formed of a material containing chromium (Cr), oxygen (O), nitrogen (N), and carbon (C),
• wherein the light shielding film has a laminated structure including four layers:
• a first layer, a second layer, a third layer, and a fourth layer, or four layers:
• a first layer, a third layer, a second layer, and a fourth layer, in this order from the side away from the transparent substrate,
• in the laminated structure, the first layer is a layer farthest from the transparent substrate, and the fourth layer is a layer in contact with the phase shift film,
• the first layer contains chromium (Cr) and oxygen (O), with a chromium (Cr) content being 28 atom % or more and 40 atom % or less, and an oxygen (O) content being 47 atom % or more and 60 atom % or less, and the first layer has a thickness of 1 nm or more and 4 nm or less,
• the second layer contains chromium (Cr), oxygen (O), nitrogen (N), and carbon (C), with a chromium (Cr) content being 30 atom % or more and 45 atom % or less, an oxygen (O) content being 28 atom % or more and 40 atom % or less, a nitrogen (N) content being 12 atom % or more and 24 atom % or less, and a carbon (C) content being 5 atom % or more and 15 atom % or less, and the second layer has a thickness of 18 nm or more and 24 nm or less,
• the third layer contains chromium (Cr) and nitrogen (N), with a chromium (Cr) content being 50 atom % or more and 60 atom % or less, and a nitrogen (N) content being 20 atom % or more and 40 atom % or less, and the third layer has a thickness of 1 nm or more and 6 nm or less, and
• the fourth layer contains chromium (Cr), oxygen (O), and nitrogen (N), and is free of carbon (C), with a chromium (Cr) content being 35 atom % or more and 44 atom % or less, an oxygen (O) content being 42 atom % or more and 54 atom % or less, and a nitrogen (N) content being 2 atom % or more and 20 atom % or less, and the fourth layer has a thickness of 18 nm or more and 36 nm or less.