| 英文摘要 |
Since the negative impact of airborne molecular contamination (AMC) on yield rate in manufacturing process and human health has been substantially approved, the improvement of indoor air quality in clean room has attracted much attention in the recent years. This project was focused on the removal of AMC, including hydrofluoric acid, hydrochloric acid, sulfuric acid, nitric acid, tetramethylammonium hydroxide, isopropanol, acetone, propylene glycol monomethyl ether acetate, and dimethyl sulfoxide, as usually seen in most clean rooms in semi-conductor and photonic industries by using ozone and catalytic oxidation technology, which was designed and developed for the improvement of indoor air quality by our research group.
Two phases were carried out in this project. The first phase was focused on the fundamental investigation and the second phase was on the design of treatment system and equipment assembly as applied practically in clean room in Feng Chia University. In the first phase, inorganic acids and bases, and organics were optimally removed by adjusting different experimental conditions. CatalystA manufactured by our collaborated company was found to be able to efficiently decompose hydrofluoric acid, hydrochloric acid, sulfuric acid, and nitric acid more than 90 percent under the situation of packing 150 grams of absorbent catalystA and controlling inflow flowrate as 1,223 mL/min. Inorganic base, such as tetramethylammonium hydroxide, was found to be completely removed by packing 100 grams of catalystB and controlling inflow flowrate at 937 mL/min. To better enhance the removal efficiency of organic AMC compounds, heterogeneous ozonation combining ozone (8.12±0.02 ppm) and goethite catalyst (60 g) at gaseous flowrate 730 mL/min was employed in our lab experiment. Under this situation, it is found that more than 98% removal rate could be achieved for all organic compounds.
After all optimal parameters were established from our lab work, a full-scale treatment system was thus fabricated to conduct a series of tests at the clean room in Engineering College in our university. When the system was operated at an air exchange rate at 5.5 ach (air change per hour) and air flowrate at 0.18 m3/sec, it is found all inorganic acids, inorganic base, and organic AMC molecules in the indoor air were eliminated more than 90 percent within the period time of three hours, where the residual concentration of gaseous ozone was detected less than 0.01 ppm that meets the standard of OSHA regulations for indoor working place. Based on these results, the indoor air treatment system developed for the AMC purification in clean room could be potentially applied in high-tech industries, thus providing a better environment for enhancing yield rate in manufacturing process. In addition, the operating cost of the catalytic oxidation equipment is approximately estimated to be NT$ 31,633 per year.
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