| AVS 54th International Symposium | |
| Plasma Science and Technology | Monday Sessions |
| Session PS1-MoM |
| Session: | Plasma Modeling |
| Presenter: | G. Kokkoris, NSCR Demokritos, Greece |
| Authors: | G. Kokkoris, NSCR Demokritos, Greece V. Constantoudis, NSCR Demokritos, Greece G. Boulousis, NSCR Demokritos, Greece P. Angelikopoulos, NSCR Demokritos, Greece E. Gogolides, NSCR Demokritos, Greece |
| Correspondent: | Click to Email |
The control and understanding of roughness formation during plasma etching is of primary importance in micro- and nano-fabrication technology. In one hand, the roughness of the surfaces of fabricated features may degrade electrical, optical or other device performance. On the other hand, there are beneficial effects of high surface roughness, e.g., in the fabrication of super-hydrophobic surfaces.1 In this work, a stochastic (Monte Carlo) simulator is used for the study of the surface roughness formation and evolution during plasma etching. The etched film is represented by cells. Shadowing and reemission of particles are taken into account. The trajectory of each particle is calculated until sticking on a cell. The interaction of the particles with the cells is defined by the sticking probability and the etching yield. The focus of the simulation is on Si etching by fluorine-containing plasmas. A common finding of past works devoted to investigation of roughness origins on plasma etched Si surfaces was the increase of the surface roughness, i.e., the root mean square roughness, versus etching time.2,3,4 In a previous work2, by using a (1+1)D stochastic simulator, we also demonstrated that the experimentally observed dual scale roughness is captured by a simple model including reactive neutral species, ions and etch inhibitors; the latter may come from sputtering of the electrode and the reactor-wall (hard inhibitors). In this work, we attempt to quantitatively reproduce all surface roughness parameters, e.g., correlation length, by a) refining model parameters, b) including another type of etch inhibitors (soft inhibitors) produced in the bulk phase of the plasma reactor, c) taking into account surface diffusion, and d) using a (2+1)D simulation tool. Atomic Force Microscope (AFM) images of Si surfaces etched by SF6 plasma are characterized and compared to the simulation results.
1 N. Vourdas, A. Tserepi, E. Gogolides, Nanotechnology 18,125304(2007).
2 P. Angelikopoulos, V. Constantoudis, G. Kokkoris, G. Mpoulousis, P. Xidi, and E. Gogolides, AVS 53rd, San Francisco, USA, November 12-17, 2006.
3 Y.-P. Zhao, J. T. Drotar, G. C. Wang, and T. M. Lu, Phys. Rev. Lett. 82, 4882 (1999).
4 E. Gogolides, C. Boukouras, G. Kokkoris, O. Brani, A. Tserepi, and V. Constantoudis, Microelectron. Eng. 73-74, 312 (2004).