| AVS 62nd International Symposium & Exhibition | |
| Plasma Science and Technology | Wednesday Sessions |
| Session PS+SS+TF-WeM |
| Session: | Atomic Layer Etching (ALE) and Low-Damage Processes I |
| Presenter: | Florentin Chambettaz, Univ. Grenoble Alpes-CNRS-CEA/Minatec-LTM,38000 Grenoble-France |
| Authors: | F. Chambettaz, Univ. Grenoble Alpes-CNRS-CEA/Minatec-LTM,38000 Grenoble-France L. Vallier, Univ. Grenoble Alpes-CNRS-CEA/Minatec-LTM,38000 Grenoble-France J. Dubois, Univ. Grenoble Alpes-CNRS-CEA/Minatec-LTM,38000 Grenoble-France O. Joubert, Univ. Grenoble Alpes-CNRS-CEA, France |
| Correspondent: | Click to Email |
In the pace of downscaling in microelectronic, current plasma etching processes show their limits. Actually for critical dimension smaller than 10 nm, atomic precision has to be reached during etching. In this study we are developing an Atomic Layer Etching (ALE) process by focusing on the induced damages related to the chemical and physical interaction(s) with hydrogen (This subject has already been broached in other studies on graphene [1] or carbon nanotubes [2]) and helium plasmas. Hydrogen plasmas have been used for years in the microelectronic industry and studied in the fields of deposition (PECVD, Plasma Enhanced Chemical Vapor Deposition), surface processing (surface passivation, hydrogenation) and plasma etching [3]. However the mechanisms related to these processes are not fully understood yet mainly because hydrogen is an element with peculiar characteristics such its low mass and its electronegativity. Helium plasmas have been also used for many years in the microelectronics industry. Helium is often employed in plasma processes as an additives gas due to its low chemical reactivity and low mass. Consequently ionic species present in the plasma and their effect are well known. To modify the surface of ultrathin layers without damaging the materials, a very low ion bombardment is required (conditions similar to those obtained in a pulsed ICP reactor [4]). At the same time, high energy plasmas are required to obtain satisfying etch rates when several nanometers have to be etched away. In this study we focus on plasma etching of silicon nitride by hydrogen plasma exposure in a commercially available 300 mm reactor, in order to develop an ALE process for spacer etching of future 10nm transistors. Several process conditions are achieved with different ion energies and ion densities, on thin silicon nitride blanket samples. The generated damages in the structure were quantified with an Electron Spin Resonance (ESR) spectroscopy and electrical characterization. The effect of these etching processes on silicon nitride will be discussed.
1. E.Despiau-Pujo, A.Davydova, G.Cunge, L.Delfour, L.Magaud, and D. B.Graves, Journal of Applied Physics, 113 (2013)
2. A.Hassanien, M.Tokumoto, P.Umek, D.Vrbanic, M.Mozetic, D.Mihailovic, P.Venturini, and S.Pejovnik, Nanotechnology, 16, 278 (2005)
3. M.Sode, T.Schwarz-Selinger, and W.Jacob, Journal of Applied Physics, 113 (2013)
4. C. Petit-Etienne, M. Darnon, P. Bodart, M. Fouchier, G. Cunge, E. Pargon, L. Vallier, O. Joubert, and S.Banna, Journal of Vacuum Science & Technology B, 31 (2013)