CHAPTER 7 TRACE WATER VAPOR ANALYSIS IN SPECIALTY GASES: SENSOR AND SPECTROSCOPIC APPROACHES MARK W. RAYNOR, 1 KRIS A. BERTNESS, 2 KEVIN C. COSSEL, 3 FLORIAN ADLER, 3 AND JUN YE 3 1 Matheson, Advanced Technology Center, Longmont, Colorado 2 National Institute of Standards and Technology, Boulder, Colorado 3 JILA, National Institute of Standards and Technology, and University of Colorado, Depart- ment of Physics, Boulder, Colorado 7.1 Introduction The analysis of water vapor impurity (often also referred to as moisture) is important in a number of specialty gas applications. However, the main driver for the development and advancement of trace moisture analysis techniques has been the microelectronics industry. The International Technology Roadmap for Semiconductors (ITRS) details the gas purity requirements for various wafer fabrication processes on their website (www.itrs.net). Oxygenated contaminants such as water vapor in the materials used and in the wafer environment are primary causes of defects and process variations that compromise yield. Because even trace levels of water in the process gases can seriously decrease device performance, analytical techniques must be capable of detecting water vapor from ppmv (umol/mol) down to the low and even sub-ppbv (nmol/mol) range. Measurement of water vapor at trace levels is quite challenging not only due to the adsorptive nature of the water molecule on metal and other surfaces, but also because of the range of gas matrices (including inert, oxide, halide, hydride, corrosive, hy- Trace Analysis of Specialty and Electronic Gases. 195 By William M. Geiger and Mark W. Raynor. Copyright © 2 0 1 3 John Wiley & Sons, Inc.