AVS 53rd International Symposium
    Plasma Science and Technology Thursday Sessions
       Session PS2-ThA

Paper PS2-ThA3
Modeling of Roughness Evolution and Instability during Si Plasma Etching

Thursday, November 16, 2006, 2:40 pm, Room 2011

Session: Plasma Modeling
Presenter: E. Gogolides, Institute of Microelectronics, NCSR "Demokritos", Greece
Authors: P. Angelikopoulos, Institute of Microelectronics, NCSR "Demokritos", Greece
V. Constantoudis, Institute of Microelectronics, NCSR "Demokritos", Greece
G. Kokkoris, Institute of Microelectronics, NCSR "Demokritos", Greece
G. Mpoulousis, Institute of Microelectronics, NCSR "Demokritos", Greece
P. Xidi, Institute of Microelectronics, NCSR "Demokritos", Greece
E. Gogolides, Institute of Microelectronics, NCSR "Demokritos", Greece
Correspondent: Click to Email
As the dimensions of fabricated features go down to nanometer scale, the roughness of their surfaces affects increasingly their physicochemical behavior and may degrade electrical, optical or other device performance. Thus, the control and understanding of roughness formation during plasma etching is of primary importance in micro- and nano-patterning technology. A common finding of past works devoted to the experimental and theoretical investigation of roughness origins and formation on plasma etched Si surfaces was the instability observed in the roughness evolution, i.e. the root mean square (rms) of surface roughness increases linearly with time. A possible explanation for the roughness instability was based@footnote 1@ on the reemission of etchant species (sticking probability 0 for first impact 1 for the second). In this work, simulation of Si surface etching at the nano-scale is done by Monte Carlo and/or continuum models. An alternative mechanism for the roughness instability is formulated, which considers the effect of reactive neutral species, ions and etching resistant species; the latter may come from the sputtering of electrode and/or reactor-wall material or from non-volatile plasma species. These etching resistant particles contribute to roughness formation by inducing local nano-masking. Preliminary simulation results suggest a sufficient reproduction of experimental trends in roughness behavior of Si surfaces etched by SF@sub 6@ plasma.@footnote 2@ AFM images are characterized and compared to the simulation results. @FootnoteText@ @footnote 1@ Y.-P. Zhao, J. T. Drotar, G. C. Wang, and T. M. Lu, Phys. Rev. Lett. 82, 4882 (1999).@footnote 2@ E. Gogolides, C. Boukouras, G. Kokkoris, O. Brani, A. Tserepi, and V. Constantoudis, Microelectron. Eng. 73-74, 312 (2004). .