AVS 64th International Symposium & Exhibition
    Plasma Science and Technology Division Friday Sessions
       Session PS+NS+SS+TF-FrM

Paper PS+NS+SS+TF-FrM6
Etching with Low Te Plasmas

Friday, November 3, 2017, 10:00 am, Room 23

Session: Atomic Layer Etching II
Presenter: Scott Walton, Naval Research Laboratory
Authors: S.G. Walton, Naval Research Laboratory
D.R. Boris, Naval Research Laboratory
S.C. Hernández, Naval Research Laboratory
S.G. Rosenberg, ASEE Postdoctoral Fellow, NRL
H. Miyazoe, IBM T.J. Watson Research Center
A.V. Jagtiani, IBM T.J. Watson Research Center
S.U. Engelmann, IBM T.J. Watson Research Center
E.A. Joseph, IBM T.J. Watson Research Center
Correspondent: Click to Email
Processing with atomic layer precision requires the ability to not only add, remove or modify one monolayer of material but to also leave adjacent layers unchanged. This requires fine control over the flux of species and energy deposition at the surface. The appropriate threshold and process windows are certainly material specific but it is reasonable to assume many applications require low energy ions. Electron beam-generated plasmas are generally characterized by high charged particle densities (1010- 1011 cm-3), low electron temperatures (0.3 - 1.0 eV), and in reactive gas backgrounds, a relatively low radical production rate compared to discharges. The flux at the surface will thus be characterized by a comparatively large amount of ions whose energies are < 5 eV, a value commensurate with the bond strength of most materials. Ion energies can be raised with substrate biasing, which makes these sources well-suited to meet the needs of energy requirements for precise, selective etching. In this work, we discuss SiN etching using pulsed, electron beam generated plasmas produced in SF6 backgrounds. We pay particular attention to the etch rates, selectivity (vs. carbon films, Si and SiO2), and patterning as function of operating parameters such as relative gas concentration, operating pressure, and substrate bias. These results are compared with plasma diagnostics to gain a better understanding of the process requirements and windows for threshold etching of SiN. This work is partially supported by the Naval Research Laboratory base program.