Inorganic acid and ammonia emission factors in semiconductor processes

This study examines the emission factors (the amount of pollutant emissions per unit of chemical usage after passing through pollution control devices) of inorganic acids, and ammonia from nine semiconductor manufacturing facilities belonging to five different technological nodes: 1.2 μm, 0.6-0.18 μm, 0.18-0.13 um, 90-40 nm, 28-12 nm, for the years 2020 to 2022. It is found that the emission factors of hydrochloric acid, sulfuric acid, hydrofluoric acid, and ammonia are 0.0017 kg/L, 0.0002 kg/L, 0.0017-0.013 kg/L, and 0.002 kg/L, respectively, for the period of 2020 to 2022. It is also worth noting that the emission factors for inorganic acids, typically the 1.2 μm generation, are lower than those reported in the literature (hydrochloric acid: 0.0096 kg/L, sulfuric acid: 0.0016 kg/L, hydrofluoric acid: 0.0075 kg/L). Moreover, it is discovered that the emission factors for inorganic acids generally showed a decreasing trend with the advancement of the manufacturing process. On the contrary, the emission factor for ammonia rises with an increase in the NH₄⁺ ions concentration in the scrubbing water of the scrubber tower. Notably, ammonia emerges as the dominant emission species, and its proportion of overall emissions tend to increase as the manufacturing processes become more advanced. This research will help sheds light on the critical aspects of gas emission in the semiconductor industry.