Abstract
The plasma-chemical cyclic process with alternation of etching and passivation stages (steps) is used to form trenches several tens of nanometers in width in silicon. The developed technology is characterized by a small duration of the stages (about 1 s); at each step, the etching time amounts to fractions of a second with a considerable amount of time being spent on the removal of a passivation layer from the bottom of the trench. The time of a pause between the steps is shown by the experiments to be a crucial parameter affecting the profile shape. To improve the selectivity of the etching process with respect to the mask, we use low values of the RF bias at the etching step (10–20 W) and rather high working pressures (more than 7 Pa). The experiments show that trenches can be formed with a mask underetch of about 2–3 nm, which is comparable to the wall roughness, for a high selectivity of the etching process with respect to the mask. For the trenches formed, the width is 30–50 nm, the aspect ratio is above 30, and the wall slope is 89°–90°.
Similar content being viewed by others
References
Laermer, F. and Schilp, A., US Patent 5501893, 1996.
Averkin, S.N., Valiev, K.A., Myakon’kikh, A.V., Orlikovskii, A.A., Rudenko, K.V., Rylov, A.A., Sukhanov, Ya.N., Tyurin, I.A., Fadeev, A.V., and Yurkov, A.E., Development of low-temperature plasma-chemical processes and a line of plasma installations for micro- and nanotechnologies, Trudy FTIAN (Proc. FTI RAS), 2005, vol. 18, pp. 121–137.
Morton, K.J., Nieberg, G., Bai, S., and Choul, S.Y., Wafer-scale patterning of sub-40 nm diameter and high aspect ratio (>50: 1) silicon pillar arrays by nanoimprint and etching, Nanotecnology, 2008, no. 19, pp. 1–6.
Hung Yung-Jr, Lee San-Liang, Thibeault, B.J., and Coldren, L.A., Realization of silicon nanopillar arrays with controllable sidewall profiles by holography lithography and a novel single-step deep reactive ion etching, in Mater. Res. Soc. Symp. Proc., 2010, vol. 1258, p. Q14–02.
Gu, X., Liu, Z., Gunkel, I., Chourou, S.T., Woo, H.S., Olynick, D.L., and Russell, T.P., High aspect ratio sub-15 nm silicon trenches from block copolymer templates, Adv. Mater., 2012, no. 24, pp. 5688–5694.
Owen, K.J., van der Elzen, B. Peterson, R.L., and Najafi, K., High aspect ratio deep silicon etching, MEMS, 2012.
Parasuraman, J., Summanwar, A., Marty, F., Basset, Ph., Angelescu, Dan E., and Bourouina, T., Deep reactive ion etching of sub-micrometer trenches with ultra high aspect ratio, Microelectron. Eng., 2014, no. 113, pp. 35–39.
Averkin, S.N., Zhikharev, E.N., Lukichev, V.F., Orlikovskii, A.A., Rylov, A.A., and Tyurin, I.A., Anisotropic plasma-chemical etching of deep trenches in silicon of sub-100 nm thickness through electronresistive mask, Integral, 2013, vol. 71, no. 3.
Author information
Authors and Affiliations
Corresponding author
Additional information
Original Russian Text © S.N. Averkin, V.F. Lukichev, A.A. Orlikovskii, N.A. Orlikovskii, A.A. Rylov, I.A. Tyurin, 2015, published in Mikroelektronika, 2015, Vol. 44, No. 2, pp. 98–107.
Rights and permissions
About this article
Cite this article
Averkin, S.N., Lukichev, V.F., Orlikovskii, A.A. et al. Anisotropic trench etching of silicon with high aspect ratio and aperture of 30–50 nm in a two-stage plasma-chemical cyclic process. Russ Microelectron 44, 79–88 (2015). https://doi.org/10.1134/S106373971502002X
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S106373971502002X