| AVS 56th International Symposium & Exhibition | |
| Plasma Science and Technology | Thursday Sessions |
| Session PS2-ThA |
| Session: | Plasma Diagnostics, Sensors, and Control II |
| Presenter: | N. Sadeghi, Université Joseph Fourier de Grenoble and CNRS-UJF-INPG, France |
| Authors: | N. Sadeghi, Université Joseph Fourier de Grenoble and CNRS-UJF-INPG, France G. Cunge, CNRS-UJF-INPG, France D. Vempaire, CNRS-UJF-INPG, France M. Touzeau, CNRS-UJF-INPG, France R. Ramos, CNRS-UJF-INPG, France |
| Correspondent: | Click to Email |
External cavity tunable diode lasers (DL) and Light Emitting Diodes (LEDs) are cost effective and easy to use tools that can be easily implemented for the diagnostics of process plasmas. We have used these techniques to characterize plasmas produced in several industrial etch reactors (Applied Materials and LAM Research) and to better understand the interaction mechanisms of the plasma with surfaces present: wafers or/and reactor walls.
Using near infrared DLs, we deduce the gas temperature in different silicon etch plasmas (Cl2, CF4, SF6,..) from the Doppler width of absorption lines from argon metastable atoms when traces of argon is added to the process gas [1]. Absorption and Laser Induced Fluorescence experiments with a blue DL permits to map up the angular dependent velocity distribution function of aluminum atoms sputtered from a RF biased Aluminum wafer under argon ion bombardment [2].
We have shown that the sensitivity of Broad Band Absorption Spectroscopy (BBAS) can be enhanced by at least one order of magnitude when a LED is used as a light source [3]. Thanks to the high stability of the LEDs, it is also possible to perform time-resolved measurements of radicals densities in pulsed plasmas [4]. With a 350 nm LED, the time variation of Cl2 density down to 3 mTorr can be measured with a time resolution of about 10 millisecond [3]. With a 275 nm LED, we have measured the decay time in the afterglow of the BCl radical produced in BCl3/Cl2 plasmas. It has been shown that the main loss mechanism of BCl radical is its gas phase reaction with Cl2 to form BCl2 molecule [4].
[1] G. Cunge, R. Ramos, D. Vempaire, M. Touzeau, M. Nejbauer, and N. Sadeghi, JVST A 27, 471 (2009)
[2] R. Ramos, G. Cunge, M. Touzeau, and N. Sadeghi, J. Phys. D: Appl. Phys. 41, 152003 (2008)
[3] G.Cunge, D.Vempaire, M.Touzeau and N.Sadeghi, Appl. Phys. Letters 91, 231503 (2007)
[4] D.Vempaire and G.Cunge, Appl. Phys. Letters 94, 21504 (2009)