Reflective mask blank for EUV lithography
AssigneeAGC Inc.
InventorsHirotomo Kawahara, Hiroyoshi Tanabe, Toshiyuki Uno, Hiroshi Hanekawa, Daijiro Akagi
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Abstract
A reflective mask blank for EUV lithography includes a substrate, a reflective layer for reflecting EUV light, and an absorption layer for absorbing EUV light. The reflective layer and the absorption layer are formed on or above the substrate in this order. The absorption layer contains tantalum (Ta) and niobium (Nb), and the absorption layer has a composition ratio Ta:Nb of Ta (at %) to Nb (at %) of from 4:1 to 1:4. Among diffraction peaks derived from the absorption layer observed at 2θ: from 20° to 50° by out-of-plane XRD method, a peak having the highest intensity has a half width FWHM of 1.0° or more.
Claims17
A reflective mask blank for EUV lithography, comprising a substrate, a reflective layer for reflecting EUV light, and an absorption layer for absorbing EUV light, the reflective layer and the absorption layer formed on or above the substrate in this order,
- wherein the absorption layer comprises tantalum (Ta) and niobium (Nb), and the absorption layer has a composition ratio Ta:Nb of Ta (at %) to Nb (at %) of from 4:1 to 1:4, and
- wherein among diffraction peaks derived from the absorption layer observed at 2θ:
- from 20° to 50° by out-of-plane XRD method, a peak having the highest intensity has a half width FWHM of 1.0° or more.
Dependencies are inferred from the claim text.