Modeling and Simulation of A

Title of Dissertation: MODELING AND SIMULATION OF A TUNGSTEN CHEMICAL VAPOR DEPOSITION REACTOR Hsiao-Yung Chang, Doctor of Philosophy, 2000 Dissertation directed by: Assistant Professor Raymond A. Adomaitis Department of Chemical Engineering Chemical vapor deposition (CVD) processes are widely used in semiconductor device fabrication to deposit thin lms of electronic materials. Physically based CVD modeling and simulation methods have been adopted for reactor design and process optimization applications to satisfy the increasingly strigent processing requirements. In this research, an ULVAC ERA-1000 selective tungsten chemical vapor deposition system located at the University of Maryland was studied where a temperature di erence as large as 120 C between the system wafer temperature reading and the thermocouple instrumented wafer measurement was found during the manual processing mode. The goal of this research was to develop a simpli ed, but accurate, three-dimensional transport model that is capable of describing the observed reactor behavior. A hybrid approach combining experimental and simulation studies was used for model development. Several sets of experiments were conducted to investigate the e ects of process parameters on wafer temperature. A three-dimensional gas ow and temperature model was developed and used to compute the energy transferred across the gas/wafer interface. System dependent heat transfer parameters were formulated as a nonlinear parameter estimation problem and identi ed using experimental measurements. Good agreement was found between the steady-state wafer temperature predictions and experimental data at various gas compositions, and the wafer temperature dynamics was successfully predicted using a temperature model considering the energy exchanges between the thermocouple, wafer, and showerhead. MODELING AND SIMULATION OF A TUNGSTEN CHEMICAL VAPOR DEPOSITION REACTOR