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Proceedings Paper

EUV mask development: material and process
Author(s): Jenspeter Rau; Hermann Wendt; Josef Mathuni; Christoph Stepper; Albrecht Ehrmann; Frank-Michael Kamm
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Paper Abstract

Extreme ultraviolet lithography (EUVL) is one of the most promising technologies for wafer feature sizes of below 50nm. The illumination wavelength will be approximately 13.5nm and consequently no transmissive optics can be used for this soft X-ray light. For several years intensive research work has been performed in different programs mainly through EUV-LLC, ASET and PREUVE. This has resulted in providing solutions for the most critical tasks of EUVL - powerful sources, defect free mask blanks and environmentally stable optics of high reflectivity. During the development with EUV-LLC an engineering test stand for illumination has been built which will be a powerful tool for the development for EUVL masks. We have studied the patterning of a EUVL mask for process development and repair tests. The material was a standard Cr absorber (as used in production) and a SiO2 buffer layer. The process investigation was focused on the dry etch stop behaviour of the etch processes and also on cleaning issues. The mask concept favoured today for EUVL masks is very similar to the masks used in production; consequently most work is performed on Cr as the absorber material and SiO2 as the buffer material. From results presented in recent years we can surmise that Cr and TaN are at present the most promising candidates as absorber materials. However it is also known that it will be very difficult to develop an etch-bias free process for Cr. In this paper we shall present our results detailing the etch properties of Ta and TaN as an absorber material. TaN is shown to be a promising absorber material. In addition, the impact of mask properties on placement and bow has been investigated with finite element calculations.

Paper Details

Date Published: 16 August 2002
PDF: 6 pages
Proc. SPIE 4764, 18th European Conference on Mask Technology for Integrated Circuits and Microcomponents, (16 August 2002); doi: 10.1117/12.479358
Show Author Affiliations
Jenspeter Rau, Infineon Technologies AG (Germany)
Hermann Wendt, Infineon Technologies AG (Germany)
Josef Mathuni, Infineon Technologies AG (Germany)
Christoph Stepper, Infineon Technologies AG (Germany)
Albrecht Ehrmann, Infineon Technologies AG (Germany)
Frank-Michael Kamm, Infineon Technologies AG (Germany)

Published in SPIE Proceedings Vol. 4764:
18th European Conference on Mask Technology for Integrated Circuits and Microcomponents
Uwe F. W. Behringer, Editor(s)

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