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7.1.4 Surface Propagation

For the surface propagation according to the deposition rates resulting from
the previously described FEM calculations a rate dependent isotropic model for
the cell-based topography simulator was used.
In contrast to the low-pressure model from the previous chapter the deposition
rates for the high-pressure model are not calculated internally within the
topography simulator but read from the external AMIGOS result file.
The file contains the vertices of the triangles generated with the surface
extraction from Section 7.1.1 and an additional rate value for each vertex
resulting from the diffusion/reaction FEM calculation. The rate values of the
triangle vertices which are located in the center of the exposed faces of the
surface cells are directly assigned as deposition rates to the corresponding
surface cells. Due to the coarsening applied in the surface extraction
the triangles are in general much bigger than the cube surfaces of the cellular
surface representation (cf. Fig. 7.2) and not all surface cells find a
corresponding rate value at a vertex of the triangulated surface. Therefore the
rate of these cells is assigned by a linear interpolation of the deposition
rates at the triangle vertices.

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W. Pyka: Feature Scale Modeling for Etching and
Deposition Processes in Semiconductor Manufacturing