| Author(s): |
S Bajt; H N. Chapman; Nhan Nguyen; J Alameda; J C. Robinson; M Malinowski; E Gullikson; Andrew Aquila; Charles S. Tarrio; Steven Grantham; |
| Title: |
Design and Performance of Capping Layers for Extreme-Ulatraviolet Multilayer Mirrors |
| Published: |
October 01, 2003 |
| Abstract: |
Multilayer lifetime has emerged as one of the major issues for the commercialization of extreme-ultraviolet lithography (EUVL). We describe the performance of an oxidation-resistant capping layer of Ru atop multilayers that results in a reflectivity above 69 % at 13.2 nm, which is suitable for EUVL projections optics and has been tested with acclerated electron-beam and extreme-ultraviolet (EUV) light in a water-vapor environment. Based on accelerated exposure results, we calculated multilayer lifetimes for all reflective mirrors in a typical commercial EUVL tool and concluded that Ru-capped multilayers have {approximately equal to} 40 x longer lifetimes thatn Si-capped multilayers, which translates to 3 months to many years, depending on the mirror dose. |
| Citation: |
Applied Optics |
| Volume: |
42 |
| Issue: |
No. 28 |
| Keywords: |
capping layers;EUV;extreme ultraviolet lithography;mirrors;multilayer mirrors;optics;oxidation resistance;reflectivity;ruthenium |
| Research Areas: |
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