| AVS 64th International Symposium & Exhibition | |
| Plasma Science and Technology Division | Tuesday Sessions |
| Session PS-TuM |
| Session: | Advanced FEOL/Gate Etching |
| Presenter: | Indira Seshadri, IBM Research Division |
| Authors: | I.P. Seshadri, IBM Research Division A. DeSilva, IBM Research Division Y. Mignot, IBM Research Division W. Xu, IBM Research Division L. Meli, IBM Research Division J. Guo, IBM Research Division S. Sieg, IBM Research Division J.C. Arnold, IBM Research Division N. Felix, IBM Research Division |
| Correspondent: | Click to Email |
Extreme ultraviolet (EUV) lithography enables single expose patterning of fine-pitch features, eliminating the need for complex multiple patterning schemes. However, reduction of line width/line edge roughness (LER/LWR) to match multiple patterning is a fundamental challenge with EUV. Typical EUV patterning stacks consist of resist, hardmask and planarizing organic layer, and reduction of both the post-lithography resist LWR and the post hardmask etch LWR are key to achieving final feature targets. With EUV eliminating the requirement for reflectivity control, hardmask materials may be chosen based on high etch selectivity to resists, stack aspect ratio reduction and low defectivity (eg. Si-containing films). However, recent work1,2 has shown that hardmask choice can significantly impact fundamental aspects of the lithography that are strongly correlated to LER/LWR, such as dose, process window and EUV secondary electron capture through interactions at the resist-hardmask interface. Here, we demonstrate the impact of different classes of hardmask materials on LWR in fine pitch metal line features, post litho and post etch. With three classes of hardmasks – Organic spin-on films, inorganic deposited Si-based films, and metal containing films, we first evaluate post lithography LWR with low and high sensitivity resists and dipole and quadrupole illumination shapes. We then characterize LWR after under layer open with optimal etch chemistries to reach target line/space sizes. With frequency analysis of LWR3, we present fundamental mechanisms that explain the LWR trends arising from resist-illumination-hardmask interaction and etch based LWR smoothing for each class. Our results provide a key knob to aid hardmask selection to meet LWR targets for future nodes
1. A. DeSilva, I. Seshadri, A. Arceo, K. Petrillo, L. Meli, B. Mendoza, Y. Yao, M. Belyansky, S. Halle, N. Felix, “Study of Alternate hardmasks for extreme ultraviolet patterning”, J. Vac. Sci. Technol. B 36 (6), 2016.
2. D. De Simone, Y. Vesters,A. Shehzad, G. Vandenberghe, P. Foubert, C. Beral, D. Van den Heuvel M. Mao, F. Lazzarino, “Exploring the readiness of EUV photo materials for patterning advanced technology nodes,” Proc. SPIE 10143 (2017).
3. R. Bonam, C. Liu, M. Breton, S. Sieg, I. Seshadri, N. Saulnier, J. Shearer, R. Muthinti, R. Patlolla, H. Huang,” Comprehensive analysis of line-edge and line-width roughness for EUV lithography”, Proc. SPIE 10143 (2017).