Photomask blank, photomask, and method for manufacturing photomask blank

摘要

A photomask blank for producing a photomask to which an ArF excimer laser light is applied. The blank includes a light transmissive substrate on which a thin film having a multilayer structure is provided. The thin film has a light-shielding film in which a back-surface antireflection layer, a light-shielding layer and a front-surface antireflection layer are laminated in this order. The light-shielding layer comprises chromium and nitrogen, and the chromium content is more than 50 atomic %. The front-surface antireflection layer and the back-surface antireflection layer each has an amorphous structure made of a material comprising chromium, nitrogen, oxygen and carbon. The chromium content ratio of the front-surface antireflection layer and the back-surface antireflection layer is 40 atomic % or less. A first sum of nitrogen content and oxygen content of the back-surface antireflection layer is less than a second sum of nitrogen content and oxygen content of the front-surface antireflection layer.

主权项

1. A photomask blank for producing a photomask to which an ArF excimer laser light is applied, wherein:
a thin film having a multilayer structure is provided on a light transmissive substrate; the uppermost layer of the thin film has an amorphous structure made of a material comprising chromium, nitrogen and oxygen; and the Cr content is 35 atomic % or less, and the sum of the N content and the O content is 50 atomic % or more.