Extreme ultraviolet (EUV) lithography is the leading candidate for the manufacture of semiconductor devices at the hp- 22-nm technology node and beyond. The Selete program covers the evaluation of manufacturability for the EUV lithography process. So, we have begun a yield analysis of hp-2x-nm test chips using the EUV1 full-field exposure tool. However, the resist performance does not yet meet the stringent requirements for resolution limit, sensitivity, and line edge roughness. We reported on Selete standard resist 4 (SSR4) at the EUVL Symposium in 2009. Although it has better lithographic performance than SSR3 does, pattern collapse limits the resolution to hp 28 nm. To improve the resolution, we need to optimize the process so as to prevent pattern collapse. An evaluation of SSR4 for the hp-2x-nm generation revealed that a thinner resist and the use of a TBAH solution for the developer were effective in mitigating this problem. Furthermore, the use of an underlayer and an alternative rinse solution increased the exposure latitude by preventing pattern collapse when the resist is overexposed. These optimizations improved the resolution limit to hp 22 nm.

Date Published: 20 March 2010
PDF: 11 pages
Proc. SPIE 7636, Extreme Ultraviolet (EUV) Lithography, 76360S (20 March 2010); doi: 10.1117/12.846088

Published in SPIE Proceedings Vol. 7636:
Extreme Ultraviolet (EUV) Lithography
Bruno M. La Fontaine, Editor(s)