Three-dimensional simulation of HPCVD - Linking continuum transport and reaction kinetics with topography simulation

For wafer sizes in state-of-the-art semiconductor manufacturing ranging up to 300 mm, the uniformity of processes across the wafer becomes a very impo rtant issue. We present a fully three-dimensional model for the feature sca le simulation of continuum transport and reaction determined high-pressure chemical vapor deposition processes suitable for the investigation of such nonuniformities. The newly developed three-dimensional approach combines to pography simulation, meshing, and finite element method tools, and allows s imulations over arbitrary geometries such as structures resulting from nonu niform underlying physical vapor deposition films. This enables the examina tion of film profile variations across the wafer for multistep processes co nsisting of low- and high-pressure parts such as Ti/TiN/W plug-fills. Addit ionally, the model allows a very flexible formulation of the involved gas c hemistry and surface reactions and can easily be extended to process chemis tries including gas phase reactions of precursors as observed in deposition of silicon dioxide from tetraethylorthosilicate (TEOS), We show simulation examples for a tungsten deposition process, which is applied as last step in a Ti/TiN/W plug-fill. For filling of an L-shaped trench, we show the tra nsition from transport to reaction limited process conditions.