High-reflective cylindrical-nanostructure multilayer mirrors for extreme ultraviolet radiation
Journal
Physica Scripta
Journal Volume
100
Journal Issue
3
Start Page
035521
ISSN
0031-8949
1402-4896
Date Issued
2025-03-01
Author(s)
Abstract
Extreme ultraviolet (EUV) is used in current semiconductor fabrication processes, and molybdenum (Mo) and silicon (Si) multilayers are often used for reflection mirrors. We propose hybrid structure multilayers that utilize cylindrical Mo and Si with vacuum space in each layer, and we call it cylindrical-nanostructure multilayer mirror which can be fabricated by current semiconductor processes. This practicality of our design is a crucial factor, as it leads to an increase in the refractive index and a decrease in the extinction coefficient in each layer, and it results in an enhancement of constructive interference within the multilayer stack. Based on the numerical simulation results using the finite-difference time-domain method, the reflectivity can be increased from 73-75% for a conventional 40-period Mo/Si multilayer to add more 2-3% for our proposed cylindrical-nanostructure multilayer mirror. As it often needs 8 to 12 reflection mirrors in EUV lithography, our proposed design can be used as high-reflectivity mirrors for EUV radiation and to increase the chip production under the same EUV light source.
Subjects
extreme ultraviolet (EUV) radiation
mirror
multilayer
nanostructure
thin films
Publisher
IOP Publishing
Type
journal article