イオン化と静電分離を利用したガス純化技術 [in Japanese] High Purification Technique for Gasses by Ionization and Electrical Migration [in Japanese]
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Various high purity process gases are used in the semiconductor manufacturing process. Contamination of process gases by molecular contaminants from pipe wall and gas transport system is inevitable. In order to ensure the high purity of process gas, direct purification technique at the point of use is required. We propose a new separation technique for molecular contamination, which utilizes preferential ionization and electrical migration of ions. In the present work, gas flow containing volatile organic compound (VOC) vapor is divided into two flows while irradiating the flow with alpha-ray or soft X-ray under DC electric field. Ionized VOC vapor in one flow electrically migrates into the other flow causing VOC rich and poor flows. The maximum VOC separation efficiency is 67 % from the nitrogen gas containing toluene vapor of 0.15 ppm. The VOC separation efficiency increases with decrease in VOC concentration. The separation of VOC is affected by carrier gas components. The effective separation of VOC requires a given irradiation time for VOC molecules to acquire the electrical charge from carrier gas ions. When the irradiation zone is sufficiently large, the VOC separation efficiency is determined by the separation efficiency of cations.
- Earozoru Kenkyu
Earozoru Kenkyu 17(2), 115-121, 2002-06-20
Japan Association of Aerosol Science and Technology