Broadband and time-resolved absorption spectroscopy with light emitting diodes: Application to etching plasma monitoring

Gilles Cunge (1) , David Vempaire (2) , Michel Touzeau , Nader Sadeghi (3)

1 LTM - Laboratoire des technologies de la microélectronique
2 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
3 LIPhy - Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères]

Broad band absorption spectroscopy is widely used to measure the concentration of radicals, which is important to understand the physical chemistry of many plasmas. It is possible to increase the sensitivity of this technique and to perform time-resolved measurement by using light emitting diodes (LEDs) as a light source. The method is applied to detect CF2 radicals and Cl2 molecules in high density plasmas. The detection limit over 10ms integration time is as low as 3mTorr of Cl2. We conclude that the absorption spectroscopy with LEDs opens possibilities for precise process control and fundamental analysis of reactive media.

Domaines: Physique [physics]

Gilles Cunge, David Vempaire, Michel Touzeau, Nader Sadeghi. Broadband and time-resolved absorption spectroscopy with light emitting diodes: Application to etching plasma monitoring. Applied Physics Letters, 2007, 91 (23), pp.1503. ⟨10.1063/1.2822448⟩. ⟨hal-00384286⟩