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 important issue. We present a fully three-dimensional model for the feature scale 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 topography simulation, meshing, and finite element method tools, and allows simulations over arbitrary geometries such as structures resulting from nonuniform underlying physical vapor deposition films. This enables the examination of film profile variations across the wafer for multistep processes consisting of low- and high-pressure parts such as Ti/TiN/W plug-fills, Additionally, the model allows a very flexible formulation of the involved gas chemistry and surface reactions and can easily be extended to process chemistries 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 transition from transport to reaction limited process conditions.