Trace Water Vapor Determination in Nitrogen and Corrosive Gases Using Infrared Spectroscopy

The generation of particles in gas handling systems as a result of corrosion is a major concern in the microelectronics industry. The corrosion can be caused by the presence of trace quantities of water in corrosive gases such as HCl or HBr. Presently there are several commercial instruments that are capable of detecting trace water vapor with detection limits as low as 50 ppb in N2. However, none of these commercially available instruments are compatible with corrosive gases. FTIR spectroscopy has been shown to be a method that can be made compatible with corrosive gases and is capable of detecting low ppb levels of water vapor. Furthermore, the use of chemometric multivariate calibration has been shown to improve detection limits compared to conventional calibration methods that employ peak heights or areas. In this report, the application of FTIR spectroscopy combined with classical least squares multivariate calibration to detect trace H2O in N2, HCl, and HBr is discussed. Chapter 2 discusses the gas handling system and instrumentation required to handle corrosive gases. This system is used for the generation of samples used in the development of the infrared method.