Patent ID: 11971653
Assignee: SHIN-ETSU CHEMICAL CO., LTD.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A photomask blank comprising a substrate, a film made of a chromium-containing material, and a film to be processed which is formed on a substrate side of the film made of a chromium-containing material and is processed using a pattern of the film made of a chromium-containing material as an etching mask, wherein
the film made of a chromium-containing material is a layered film having a three-layer structure consisting of, in order from a side away from the substrate, a first layer, a second layer and a third layer,
the first layer containing oxygen and nitrogen, and having a chromium content of 40 atom or less, an oxygen content of 50 atom % or more, a nitrogen content of 10 atom % or less and a thickness of 6 nm or less;
the second layer containing oxygen, nitrogen and carbon, and having a chromium content of 40 atom % or less, an oxygen content of 30 atom % or more, a nitrogen content of 17 atom % or more, a carbon content of 13 atom % or less and a thickness of 46 nm or more; and
the third layer containing oxygen and nitrogen, and having a chromium content of 50 atom % or more, an oxygen content of 20 atom % or less and a nitrogen content of 30 atom % or more.