||Semiconductor and TFT-LCD processes use a significant amount of special gases. Most of these special gases are halogenated acid gases, e.g., Cl2, HCl, ClF3, and HBr, etc… The special gases are toxic to human and cause corrosion on pipes and process tools. Major treatment processes for those gases are wet scrubbing, burn + wet scrubbing and dry scrubbing processes. However, some gases have low solubility in water and burn process could cause fire hazard and consume significant energy. Semiconductor Industry Association recommends the dry local scrubber for CVD cleaning and etching as well as ion implantation. The objective of this study was to investigate the treatment ability of toxic gases from semiconductor processes by dry local scrubbers. Low pressure chemical vapor deposition process (LPCVD) was the primary target of this study and the ClF3 is used as the cleaning gas for wafer.|
Three dry local scrubbers were studied, including the regular activated carbon, activated carbon coated with NaOH and CaOH, and FeOOH catalyst. A FTIR was used to detect the target gas and byproducts from the LPCVD process as well as the byproducts after the dry local scrubbers. Results showed that the major gases from the LPCVD process are SiF4, HCl, HF and CO. ClF3 was consumed during the process. Those gases were removed by the three types of dry scrubbers with efficiency higher than 99%. However, CFCs (chlorination fluorinated carbons) and methanol were detected in the effluent gases of the two activated carbons of local scrubbers, but negligible for FeOOH. Cost comparison of the three dry scrubbers showed the waste treatment cost are major problems for the dry scrubbers. The FeOOH can be recycled locally and therefore, the operation cost of the FeOOH was lowest.
Based on these observation, it were concluded the dry local scrubbers are high efficiency, and have low maintenance, no wastewater and toxic gases and low risk on fire hazard on special gas treatment. However, the activated carbon type of local scrubber can produce significant amount of by-products and waste treatment is major problem. The FeOOH type local scrubber can overcome those problems.
||1. 余榮彬 ‘半導體工業全氟化物排放控制技術與機會 ‘TSIA, 1998|
2. 余榮彬 ‘第七屆國際半導體安全衛生環保研討會報’, 2000/09/30
3. US EPA, 1998；Global Semiconductor Industry Conference on Perfluoro Compound Emission Control, Proceeding, Monterey, CA, USA.
4. Jerry Meyers, 1998；〝Emissions Characterization Package〞, Rev 2.4, Intel
5. VOC Newsletter 1-10Issuses,KWS 2000-Project Bureau,the Netherland, 1990-1993
6. 有害空氣污染物最佳可行控制技術(BACT)電子半導體實例分析，P135， 工業污染防治 第58期 , 1996.4
7. Jacoby, William A ; Blake, Daniel M. ; Noble, Richard D. ; Koval, Carl A. “Kinetics of the trichgloroethylene in air via heterogeneous photocatalysis” Physical Organic Chemistry, CA section 22 ,1995
8. Matthews, R.W. “Photooxidation of Organic Impurities in Water Using Thin Films of Titanium Dioxide.” J. Phys. Chem., 91, 3328, 1987.
9. Ollis, D.F.; Serpone, N.; and Pelizzetti, E. 浶eterogeneous Photocatalysis in the Environment: Application of Water Purification.” In Photocatalysis Fundamentals and Applications. Serpone, N.; and Pelizzetti, E., ed.; John Wiley & Sons: New York, 1989; 603-638.
10. Akata, A., Oxidation of Water Pollutants by Ozone Photolysis Studies of Nitrobenzeneas a Model Compound. Ph.D Dissertation; Drexel University: Philadelphia, PA., 1994.
11. Bhowmick, Ｍ. And Semmens, M. J.,” Ultraviolet photooxidation for the destruction of VOCs in Air” Wat. Res., 28, p 2407,1994.
12. Lin, Shu-sung, “Interaction of H2O2 with Iron Oxides for Oxidation of Organic Compounds in Water”， Ph.D. Thesis, Drexel University, Philadelphia, PA., USA, 1997.
13. Gurol, M. D.; Lin, S.-S.; and Bhat, N. “Granular Iron Oxide as a Catalyst in Chemical Oxidation of Organic Contaminates”in “In merging Technologies in Waste Management.” ACS, edited by F. Pohland and W. Tedder, 1996.
14. Taiwan Semiconductor Industry ESH Workshop，1998,5.
15. B. Dhandapani, S.T. Oyama, “ Gas phase ozone decomposion catalysts”, Applied Catalysis B: Environmental 11 , 1997, 129 – 166.
16. Chou, C. C. and Lin, S., “Characterization of Plume Opacity of Semiconductor Wet Central Scrubbers”, paper presented at 6th Annual International Environmental, Safety and Health Conference, June 13~15, 1999.
17. Williams, M.E., Baldwin, D.G. and Manz, P.C., “Semiconductor industrial hygiene handbook”, Noyes, NJ, 1995.
18. Rand, S. D. “The Semiconductor Industry’s Model Strategy for Global Climate Protection”, Semiconductor Fabtech, 10, 99-102, 1999.
19. Beu, L., Brown P. T., Latt, J., Rapp, J. U. , Gilliland, T., Tamayo, T., Harrison, J., Davison, J., Cheng, A., Jewett, J. and Worth, W. "Current State of Technology: Perfluorocompound (PFC) Emissions Reduction. SEMATECH Technology Transfer #98053508A-TR, 1998.
20. Vartanian, V., Beu, L., Stephens, T., Rivers, J., Perez, B., and Tonnis, E., Kiehlbauch, M. and Graves, D., ”Long-Term Evaluation of the Litmas "Blue" Plasma Device for Point-of-Use (POU) Perfluorocompound and Hydrofluorocarbon Abatement”, SEMATECH Technology Transfer # 99123865A-ENG, 2000.
21. 行政院環境保護署 “污染防治技術開發與推廣專案研究：電子產業及特定行業空氣污染改善輔導示範推廣及管制標準研訂專案工作研究報告” 2001.