AVS2001 Session AT-TuP: Poster Session
Tuesday, October 30, 2001 5:30 PM in Room 134/135
Tuesday Afternoon
Time Period TuP Sessions | Topic AT Sessions | Time Periods | Topics | AVS2001 Schedule
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AT-TuP-2 Global Warming Gas Emission During Plasma Cleaning Process of Silicon Nitride PECVD Chamber Using C4F8O and Mixtures
K.J. Kim, Y.S. Ahn, N.-E. Lee, B.H. Oh, J.H. Kim, G.Y. Yeom (Sungkyunkwan University, Korea) The emission of perfluorocompounds (PFCs) into the atmosphere has caused growing concern in the semiconductor industry because of their potential global warming effects. PFCs used in plasma cleaning process of CVD chamber are mostly responsible for the global warming. Therefore, the semiconductor industry is proactively seeking ways to reduce PFCs emissions through the use of alternative process chemicals, process optimization, and abatements including destruction and recovery. Among those, the use of alternative gases is expected to be most promising. In this work, C4F8O gas was used as an alternative process chemical that has better destruction removal efficiency (DRE) than other alternative gases, such as NF3, C3F8, and C4F8. Plasma cleaning of silicon nitride using gas mixtures of C4F8O/O2, C4F8O/O2/Ar, and C4F8O/O2/N2 was investigated in order to evaluate the effects of adding different gases to C4F8O on the global warming effects. First of all, we determined an optimum cleaning condition as processing condition such as additional gases mixture ratio, total gas flow, and working pressure. Under this condition, we quantified the emitted net PFCs while cleaning silicon nitride and then compared the effects of adding different gases to C4F8O by evaluating the destruction removal efficiency (DRE) and the million metric tons of carbon equivalent (MMTCE). DRE and MMTCE were calculated by evaluating the volumetric emission using Fourier transform-infrared spectroscopy (FT-IR). DRE values as high as 98% were obtained and MMTCE values were decreased by as high as 90% compared to the case of C2F6/O2. Indirect recombination characteristics were investigated by combining the measurements of species in the chamber using optical emission spectroscopy (OES) and quadrupole mass spectroscopy (QMS), before and after the cleaning processing. |