Patent ID: 11940725
Assignee: S&S TECH CO., LTD.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A mask blank for extreme ultraviolet lithography, comprising:
a substrate;
a reflective layer formed on the substrate;
a capping layer formed on the reflective layer;
an etch stop layer formed on the capping layer; and
a phase shift layer formed on the reflective-layer etch stop layer;
wherein,
the capping layer is made of a material containing ruthenium (Ru),
the phase shift layer comprises ruthenium (Ru) and chromium (Cr), and
the etch stop layer is formed in a structure of two or more layers, an uppermost layer of the etch stop layer is made of a material containing tantalum (Ta) and oxygen (O), and a layer under the uppermost layer of the etch stop layer is made of a material containing tantalum and not containing oxygen (O).