Experimental investigation of beryllium-based multilayer coatings for extreme ultraviolet lithography
The performance of beryllium-based multilayer coatings designed to reflect light of wavelengths near 11 nm, at normal incidence, is presented. These multilayer coatings are of special interest for extreme ultraviolet lithography (EUVL). The beryllium-based multilayers investigated were Mo/Be, Ru/Be and a new material combination Mo,CiBe. The highest reflectivity achieved so far is 70% at 11.3 mn with 70 bilayers of Mo/Be. However, even though high reflectivity is very important, there are other parameters to satisfy the requirements for an EUVL production tool. Multilayer stress, thermal stability, radiation stability and long term reflectance stability are of equal or greater importance. An experimental characterization of several coatings was carried out to determine the reflectivity, stress, microstructure, and long term stability of these coatings. Theoretically calculated reflectivities are compared with experimental results for different material pairs; differences between experimental and theoretical reflectivities and bandwidths are addressed. Keywords: Extreme ultraviolet (EUV) lithography, reflective coatings, multilayer deposition, beryllium.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE Office of Defense Programs (DP) (US)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 12561
- Report Number(s):
- UCRL-JC-132917; TRN: AH200120%%308
- Resource Relation:
- Conference: Society of Photo-Optical Instrumentation Engineers, Engineering, and Instrumentation, Society for Professional Engineers, (SPIE) 44th Annual Meeting, Denver, CO (US), 07/18/1999--07/23/1999; Other Information: PBD: 30 Jul 1999
- Country of Publication:
- United States
- Language:
- English
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