| AVS 63rd International Symposium & Exhibition | |
| Plasma Science and Technology | Wednesday Sessions |
| Session PS-WeA |
| Session: | Atomic Layer Etching and Low Damage Processing |
| Presenter: | Florentin Chambettaz, Univ. Grenoble Alpes, France |
| Authors: | F. Chambettaz, Univ. Grenoble Alpes, France L. Vallier, Univ. Grenoble Alpes, France O. Joubert, Univ. Grenoble Alpes, France |
| Correspondent: | Click to Email |
As downscaling pace the microelectronic industry, current plasma etching processes show their limits. Actually for critical dimension smaller than 10 nm, atomic precision has to be reached. In this study, we are characterizing an Atomic Layer Etching (ALE) process by focusing on the induced damages related to the chemical and physical interaction(s) with hydrogen 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) [1] and plasma etching. However the mechanisms related to these processes are not fully understood yet mainly because hydrogen is an element with peculiar characteristics such as its low mass and electronegativity. Helium plasmas have been also used for many years in the microelectronics industry, mainly as an additives gas thanks to its low chemical reactivity and low mass. In order 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 [2]). At the same time, dense 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 and Helium plasma exposure in a commercially available 300 mm reactor, in order to develop an ALE process for spacer etching of future transistors [3]. Several process conditions are achieved with different ion energies and ion densities, on thin silicon nitride blanket samples. The quantity and the position in the silicon nitride of generated traps are studied with an electrical characterization. The effect of those plasma process condition on the silicon nitride etch rate 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. 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)
3. N. Posseme, O. Pollet, and S. Barnola, Applied Physics Letters, 105 (2014)