Substrate for EUV mask blanks
AssigneeAsahi Glass Company, Limited
InventorsAkio Koike, Ken Ebihara
Life of this patent
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Abstract
A substrate that is suitable for an EUV mask or an EUV mask blank and excellent in flatness, is provided. A substrate for an EUV mask blank, which is made of a silica glass containing from 1 to 12 mass % of TiO2, wherein the surface roughness (rms) in a surface quality area of the substrate is at most 2 nm, and the maximum variation (PV) of the stress in the surface quality area of the substrate is at most 0.2 MPa.
Claims33
A substrate, which is made of a silica glass containing from 1 to 12 mass % of TiO2, wherein the surface roughness (rms) in a surface quality area of the substrate is at most 2 nm, and the standard deviation (σ) of the stress in the surface quality area of the substrate is at most 0.04 MPa.
A substrate, which is made of a silica glass containing from 1 to 12 mass % of TiO2, wherein the surface roughness (rms) in a surface quality area of the substrate is at most 2 nm, and the maximum variation (PV) of the stress in the surface quality area of the substrate is at most 0.2 MPa.
Dependencies are inferred from the claim text.