Real-time in-situ chemical sensing, sensor-based film thickness metrology, and process control in W CVD process

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Xu, Yiheng
A real-time in-situ sampling system has been implemented for chemical sensing in tungsten chemical vapor deposition process (W-CVD) using mass spectrometry. Sensor integration was realized to allow synchronous capture of equipment state signals and process signals (chemical information from mass spectrometry). <p>Wafer state metrology from integrated mass spectrometry signals of different gaseous chemical species in the reaction was established with an uncertainty of 2-7 percent depending on the conversion rate of the process, which is determined by the process chemistry and processing conditions. The mass spectrometry-based wafer state metrology obtained was applied to implement fault detection and W film thickness process control: run-to-run control in H2 reduction W-CVD and real time end point control in SiH4 reduction process. <p>The results demonstrate the benefit of combining real-time mass spectrometry sensor data with equipment state information for process control. The important generic issues regarding real-time in-situ chemical sensing using mass spectrometry in the context of a multi-component chemical reaction system like W-CVD have also been discussed. <p>The accomplishments of this research demonstrate the value of in-situ chemical sensing in complex manufacturing process systems and provide clear pathways toward advanced process control methodology.