Effects of experimental parameters on NF(3) decomposition fraction in an oxygen-based RF plasma environment.
Clean procedure is one of the major emitters of perfluorinated compounds (PFCs) in semiconductor manufacturing. Nitrogen trifluoride (NF(3)) is increasingly the process gas of choice for eliminating PFC emissions. However, its toxic to human and similar global warming potential compared to most other PFCs made NF(3) warranted much more investigation. This study demonstrated a radio-frequency plasma system for decomposing NF(3). The effects of experimental parameters: input power, O(2)/NF(3) ratio, operational pressure and NF(3) feeding concentration on NF(3) decomposition fraction (eta(NF3)) and energy efficiency E(NF3) were examined in detail. The analytical results demonstrated that the NF(3) was almost completely decomposed (>99%) at input power=30W, [NF(3)](in)=1.0% and eta(NF3) increased with input power. However, adding O(2) to the system inhibited NF(3) decomposition and decreased E(NF3). Moreover, eta(NF3) and E(NF3), decreased with gradually increasing operational pressure. Notably, increasing the NF(3) feeding concentration increased molecule density, reducing eta(NF3), but increasing E(NF3). Furthermore, the products detected in the NF(3)/O(2)/Ar plasma system were NO(2), NO, N(2)O, SiF(4), N(2) and F(2). Potential reaction pathways in the oxygen-based NF(3) plasma environment were built-up and elucidated.
Wang
Ya-Fen
YF
Department of Bioenvironmental Engineering, Chung Yuan Christian University, No. 22, Pu-Jen, Pu-Chung Li, Chung-Li 320, Taiwan, ROC. yafen@url.com.tw
Wang
Lin-Chi
LC
Shih
MinLiang
M
Tsai
Cheng-Hsien
CH
D004787:Environmental Pollution / Q000517:prevention & control*; D005459:Fluorides / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D007221:Industry; D007700:Kinetics; D017672:Nitrogen Compounds / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D011846:Radio Waves; D012666:Semiconductors; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods
D017672:Nitrogen Compounds; D005459:Fluorides; D010100:Oxygen