US 8,137,872 B2 · Reflective mask blank for EUV lithography

Abstract

To provide a reflective mask blank for EUV lithography having a low reflective layer having a low reflectance in the wavelength region of EUV light and an inspection light for a mask pattern, particularly having low reflection properties in the entire wavelength region (190 to 260 nm) of an inspection light for a mask pattern, and having a high etching rate in chlorine type gas etching. A reflective mask blank for EUV lithography, comprising a substrate, and a reflective layer to reflect EUV light, an absorber layer to absorb EUV light and a low reflective layer to an inspection light (wavelength:190 nm to 260 nm) for a mask pattern, formed in this order over the substrate, wherein the low reflective layer contains silicon (Si) and nitrogen (N) in a total content of at least 95 at %, has a Si content of from 5 to 80 at %, and a N content of from 15 to 90 at %.

Claims20

Dependent claims

A reflective mask blank for EUV lithography, comprising:

a substrate;
a reflective layer which reflects EUV light;
an absorber layer which absorbs EUV light;
and
a low reflective layer which is low-reflective to an inspection light in a wavelength range of 190 nm to 260 nm for a mask pattern,
wherein the reflective layer, the absorber layer and the low reflective layer are formed over the substrate in an order of the reflective layer, the absorber layer and the low reflective layer, and the low reflective layer contains Si and N in a total content of at least 95 at % and has a Si content of from 5 to 80 at %, a N content of from 15 to 90 at %, and an O content is less than 5 at %.

3 more elements

Dependencies are inferred from the claim text.

Reflective mask blank for EUV lithography

Life of this patent

Reflective mask blank for EUV lithography

Life of this patent

Abstract

Claims20