Time Resolved Diagnostics During Low-Pressure Inductively Coupled Fluorocarbon Plasmas Instabilities
Abstract
Recently, many groups have observed instabilities in inductively coupled plasmas using electronegative gases such as O2, Cl2 or SF6. Until now, few work have been done concerning fluorocarbon plasmas (CHF3, C2F6, CF4). We observed that they can be strongly unstable and we suspect that it may affect plasma etching. For that reason, we started to characterize these instabilities, using a capacitive planar probe. This probe has the advantage to directly measure the ion flux, which is one of the most important parameter for dielectric etching in fluorocarbon plasmas, and to accurately operate even under polymerising environment. We showed that the capacitive planar probe can be efficiently used for time resolved measurements. Preliminary results indicate that the ion flux can be modulated by a factor 2 during the C2F6 instability period (to be compared with the factor 100 we measured for electron density modulation under oxygen plasma instabilities). We now use the measured ion flux to understand instability influence on plasma etching.
- Publication:
-
APS Annual Gaseous Electronics Meeting Abstracts
- Pub Date:
- September 2004
- Bibcode:
- 2004APS..GECKM1004C