Implementation of an in situ moisture sensor to improve utilization and performance of a rapid thermal processor

A novel in situ moisture sensor based on tunable diode laser spectroscopy has been used to monitor water vapor during titanium silicide formation and annealing. The relationship between water vapor level and sheet resistivity in titanium silicide formation was discussed in another recent publication. In this paper we show that the sensor is useful in optimizing purge procedures and also as a safeguard against accidental ambient contamination and similar incidents. It can be anticipated that the sensor output will eventually be fed back to the tool in order to be used directly in control of purging and other process steps.