4.3.1.1 Post Processing

After the topography simulation has completed, a polygonal representation of the modified simulation domain has to be generated. The post processing algorithm aims at taking over unchanged elements from the original Wafer, thereby restricting conversion errors between cellular and polygonal representations to the modified area.

In order to reduce the huge number of resulting triangles^4.3 and also to improve the quality of the triangulated etch front two post processing algorithms are applied.

• The Manhattan like structure that results from the etching algorithm is smoothed by moving each point of the surface a small distance. The direction and width of the movement is thereby determined as the sum of displacements of this point to all points of adjoining triangles. The displacements are indirect proportional to the distance of a point and are set to 0 if the distance exceeds a certain limit. This algorithm is performed for a certain number of iterations and shows good smoothing qualities.

• The number of triangles is reduced by removing edges that are shared by triangles that are almost (given as an angle tolerance) coplanar.

2003-03-27