Outdoor airborne contamination control for semiconductor manufacturing process

Semiconductor process can be adversely affected by airborne molecular contamination, which may arise from sources in the outdoor environment or from sources in the fab. In Taiwan, environment air pollutants could be carried in by seasonal wind from overseas or could arise from domestic agriculture and industry sources. Potential air pollution chemicals include NH₄, SO₂, H₂S, DMS or dimethyl sulfoxide (DMSO), and SF₆. Without proper defense system, these chemical contaminants could enter into the fab air circulation and interact with the processed wafers. This paper demonstrated correlation of physical and electrical defects with several potential air pollutants from the local environment in Taiwan. Furthermore, a novel UV/catalyst based system was tested for decomposition of molecular contaminant. Such system may supplement the chemical filter based filtration system in which filter replacement cost could be significant.