CF4 decomposition using low-pressure pulse-modulated radio frequency plasma

Abstract

CF4 is one of the most stable gases among perfluorocompounds (PFCs) whose decomposition is extremely difficult. In this study, CF4 decomposition was investigated using a pulse-modulated radio frequency (RF) plasma of 2 MHz, which is applicable to plasma etching and novel functional material manufacturing processes. When the absolute pressure and 100% CF4 and 99.5% O2 flow rates were set at 80 Pa and 0.1 and 0.2 NL/min, respectively, almost complete CF4 decomposition was achieved at the pulse modulation frequency range of 25 kHz to 99 kHz. The analysis of the by-product of CF4 decomposition was carried out using a CO2 gas analyzer and a Fourier transform infrared spectrophotometer (FTIR) with a pulse modulation frequency of 75 kHz. It was known that 10%, 50% and 24% of CF4 are converted to CO, CO2 and COF2, respectively. It was considered that the remaining 16% of carbon is converted to carbon particles or other organic substances. Copyright © 2006 by The Japan Society of Mechanical Engineers.