Publications Details

FTIR spectroscopy for the determination of water in corrosive gases

Rowe, R.K.; Stallard, B.R.; Espinoza, L.H.; Niemczyk, T.M.

Internal corrosion in semiconductor gas delivery systems may lead to increased particle counts in downstream fabrication tools and to catastrophic failure of the delivery system itself. The problem is particularly acute since, once the corrosion begins, it becomes a moisture reservoir to further damage the system. To keep gas systems as moisture free as possible semiconductor manufacturers employ drying filters, usually located just after the source of the process gas. Even so, the piping for corrosive gases may need to be rebuilt every few years. Careful monitoring of the moisture in the process gases can provide valuable information about the state of the gas handling system and its effect on the process integrity. Presently there are several technologies costing $50K or less that are capable of detecting trace water vapor as low as 50 ppb in N{sub 2}. However, no one type of instrument has achieved universal acceptance. In particular, all have limited compatibility with corrosive gases such as HCl and HBr. The goal of this project is to develop an in-line instrument based on infrared spectroscopy for this purpose. Earlier results leave no doubt that FTIR spectroscopy can be successfully used for trace water detection. However, important questions regarding optimal data analysis and instrument design are not yet fully answered. It is the goal of this research effort to answer these questions and to incorporate the findings into a prototype device suitable for commercialization.