Applications of in-line oxygen monitoring to a rapid thermal processing tool: diagnosing gas flow dynamics and silicidation processes

Two types of application of real-time oxygen monitoring on a production-type rapid thermal processor (RTP) are reported. Diagnosing of gas flow dynamics in an RTP chamber is described by using a tracer technique. Deviation from plug flow, which decreases purge efficiency, was observed as a function of gas flow rate. Purge design is performed on the basis of the gas flow dynamics, and the efficiency of several purge patterns was comparatively studied. Monitoring of a typical two-step RTP process for silicidation of Ti or Co was then demonstrated. Both adsorption and desorption were found to take place during annealing. Oxygen desorbs first at lower temperature (during temperature ramp) and then starts to adsorb at higher temperature. A few monolayers of oxygen is adsorbed to Ti during annealing, while less oxygen is adsorbed during Co RTP.