Multi-scale modeling of chemical vapor deposition processes for thin film technology

Chemical vapor deposition (CVD) process and equipment models aim at relating set macroscopic process conditions (such as the used gases and their respective flowrates, the operating pressure and temperature) to macroscopic and microscopic film properties (such as thickness uniformity, conformality, crystallinity and morphology, and chemical composition and purity). The first analytical models, aiming at the prediction of growth rate and uniformity only, were published in the 1970s. Since then, multi-scale, multi-physics models have been developed, based on advanced computer simulations and aiming at the comprehensive description of all relevant physical and chemical phenomena occurring at lengtht scales from sub-micrometer to meters. CVD process and equipment simulation have been applied successfully not only to optimize hydrodynamic reactor designs with respect to deposition rate and uniformity, but also to predict and control formation and transport of particles, to scale-up existing reactors to larger wafer diameters, to optimize deposition conformality, to predict doping rates, to evaluate loading effects, and to study selectivity loss. Today, CVD simulation models are being used routinely by process engineers and equipment manufacturers, and many modeling features needed for comprehensive CVD simulation have been included in commercial software codes. In this review paper, the developments-over the past decades-in comprehensive multi-scale simulation of CVD processes and equipment are described and illustrated with examples from the work performed in the authors' group. (c) 2007 Elsevier B.V. All rights reserved.