Measurement of electron temperatures and electron energy distribution functions in dual frequency capacitively coupled CF4/O2 plasmas using trace rare gases optical emission spectroscopy

Zhiying Chen, Vincent M. Donnelly, Demetre J. Economou, Lee Chen, Merritt Funk, Radha Sundararajan
2009 Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films  
Measurements of electron temperatures ͑T e ͒ and electron energy distribution functions ͑EEDFs͒ in a dual frequency capacitively coupled etcher were performed by using trace rare gas optical emission spectroscopy ͑TRG-OES͒. The parallel plate etcher was powered by a high frequency ͑60 MHz͒ "source" top electrode and a low frequency ͑13.56 MHz͒ "substrate" bottom electrode. T e first increased with pressure up to ϳ20 mTorr and then decreased at higher pressures. Increasing the bottom rf power
more » ... ulted in higher electron temperatures. Electron temperatures in 90% CF 4 +10% O 2 plasmas were similar to those in 80% CF 4 +20% O 2 plasmas. EEDF exhibited bi-Maxwellian characteristics with enhanced high energy tail, especially at pressures Ͼ20 mTorr.
doi:10.1116/1.3179162 fatcat:hcm5ruqubfau5amz2j2nbbrfqu