The concentrations and characteristics of major components in inorganic gases and fine particles were measured at the photo and etch cleanroom areas in a Taiwan semiconductor factory. The results showed that the major inorganic gases, as expressed in terms of volume concentration, were NH3 and HF at 7-10 and 4-6 ppbv, respectively. The average PM2.5mass concentration were 17.52 and 18.23 μg/m3 at the photo and etch areas, respectively, with species of Na+, NH4 +, and SO4-2 had the highest concentrations in the PM2.5 mass. And the inorganic species account for 56% and 62% of the particulate mass, respectively, at the photo and etch areas. Relatively stronger correlations were observed between NH4 + and SO4-2 with the correlation coefficient R2 of 0.62 and 0.82, respectively, at the photo and etch areas; this indicates their common source was possibly from the gas to particle formation process. And NH3 was found to co-exist with HF at the etch area due to their common source as process chemicals (NH4OH and HF) in the wet bench. In the predominant NH3-rich environment, ammonia is the basic neutralizing agent to form the ammonium aerosol in a cleanroom.
- AMCs (Airborne Molecular Contaminants)
- Diffusion denuder system (DDS)
- Semiconductor device