In-Situ Oxygen Monitoring of Rapid Thermal Process Chamber: Diagnosis of Gas Flow Dynamics and Wafer Processing

Abstract

ABSTRACTTwo types of real-time oxygen monitoring are investigated for RTP applications, i.e. addressing the basis for a state-of-the-art clean ambient technology and understanding its impact on real processes. Diagnosing of gas flow dynamics in the chamber is carried out by tracer experiments. Deviation from plug flow, which decreases purge efficiency, is found to be a function of gas flow rate. The monitoring of a typical two-step RTP process for silicidation of Ti or Co show that both adsorption and desorption take place. Oxygen is desorbed first at lower temperatures (during temperature ramp) then starts to be adsorbed at higher temperatures. In the case of Ti, a few monolayers of oxygen is adsorbed during the first RTP but less oxygen is adsorbed during the second RTP. The amount of oxygen adsorbed during Co RTP is found to be not as high as during Ti RTP.