To mitigate airborne molecular contamination through ultra-pure air system

Abstract

Airborne Molecular Contamination (AMC) has become one of the major problems in nano-technology development and manufacturing facilities. To deal with this problem, a prototype Ultra-Pure Air (UPA) system with a targeted air quality level of 10 ppt impurity was experimentally developed.The prototype UPA system presently composes two process modules; pre-treatment and post-treatment. In order to deal with the hard-to-remove airborne organic molecular substances, UV185+254nm is first used in the pre-treatment module to provide the energy needed for breaking the molecules into smaller transitional compounds. Meanwhile aerosol water droplets are introduced; these combine with the transitional compounds to form hydrophilic substances. After the “Immersing Photochemical Oxidation” reaction, the hydrophilic contaminants go through compression and condensation processes, which comprise the post-treatment module. During the air compression and condensation processes, the collision probability of the contaminants and aerosol water droplets is highly increased. Later, a dehumidification process removes the water droplets within the condensed air; this removes both the water and the dissolved contaminants. These pre and post-treatment processes yield air quality levels of less than 1 ppb of volatile organic compound (VOC); the minimum detection limit for a measuring analyzer.The purpose of this paper is to introduce the developed UPA system and to present its experimental results.