Translator Disclaimer
5 October 2005 Preparation and characterization of multilayers for EUV applications
Author Affiliations +
The dependency of EUV reflectance and of the stress present in Mo/Si/C multilayers on the constituent individual layers has been investigated. The heat treatment of highly EUV reflective Mo/Si/C multilayers has been examined in terms of annealing time and temperature. Irreversible stress change was found at annealing temperatures above 130 °C, where the change of period thickness and the change of stress increase more rapidly. It was found, that there is a saturation of stress change depending on the annealing time. Annealing at 100 °C reveals a saturation of stress change after 10 h, whereas annealing at 150 °C still shows stress reduction after 50 h. A second annealing of two samples shows a reversible stress-temperature behavior of the multilayers. Stress compensation layers for the coating of stress-mitigated Mo/Si/C multilayers were developed. The best results of composition for reflective multilayers and stress-compensation multilayers were joint together in order to fabricate stress-mitigated Mo/Si/C multilayers. Taking the condition of achieving an overall stress below ±100-150 MPa into account, two types of stress-mitigated multilayers were coated. The first type includes a buffer layer in order to compensate the compressive stress of the reflective multilayers without annealing. The stress was reduced to -76 MPa by keeping a high EUV near-normal incidence reflectance of ~70.0 %. The second type contains a thinner buffer layer and the stress reduction of the complete multilayer system was assisted by a post-annealing at 100 °C for 10 h. The stress was measured to be -108 MPa and an EUV reflectance of 69.5 % was obtained.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Th. Foltyn, S. Braun, W. Friedrich, A. Leson, and M. Menzel "Preparation and characterization of multilayers for EUV applications", Proc. SPIE 5963, Advances in Optical Thin Films II, 59632C (5 October 2005);


Back to Top