ON THE MODELING OF TRANSPORT PHENOMENA IN CHEMICAL VAPOR-DEPOSITION AND ITS USE IN REACTOR DESIGN AND PROCESS OPTIMIZATION

The properties of thin films grown by chemical vapour deposition (CVD) are strongly determined by the interaction of transport phenomena and chemical reactions in the reaction chamber. These phenomena can be studied with the use of numerical simulation models, based on fluid dynamics and reaction chemistry and describing the reactor-scale properties of the process. Additional feature-scale models can relate macroscopic process conditions to microscopic film properties. The general features of reactor-scale CVD models are described in this paper and examples of some feature-scale models are given. The use of CVD models as an aid in reactor design and process optimization and as a valuable tool in the correct interpretation of experimental data is illustrated. Special attention is given to tungsten low pressure CVD processes in single-wafer reactors. It is described how the use of reactor-scale and feature-scale CVD models has led to the development of a highly improved blanket tungsten feature filling process, combining a high and uniform growth rate and step coverage with a very economic use of reactants.