Patent ID: 6484305
Filing Date: 2002-11-19
Classification: G06F

Abstract:
In semiconductor device process simulation, an impurity quantity transfer device which transfers, according to deformation of a semiconductor device, an impurity value defined on a first mesh generated on said semiconductor device before the deformation to a second mesh generated on said semiconductor device after the deformation, comprising:control volume generation means for generating, on said second mesh, a grid-based control volume region bridging a plurality of mesh elements, said plurality of mesh elements sharing a grid point on said second mesh as a vertex, and said grid-based control volume region being a polygon having circumcenters of each of the bridged plurality of mesh elements on said second mesh as vertices; subdivisional control volume generation means for subdividing, on a mesh element basis on said first mesh, a region of a mesh element, and thereby generating at least one mesh-based control volume, wherein: said subdivisional control volume generation means generates, on said first mesh, a first-mesh grid-based control volume region, bridging a plurality of mesh elements sharing a grid point on said first mesh, said first-mesh grid-based control volume region comprising a polygon having circumcenters of each of the bridged plurality of mesh elements on said first mesh as vertices, each mesh element on said first mesh is a polygon having grid points of said first mesh as vertices, and said region of a mesh element, which is subdivided by said subdivisional control volume generation means, is that portion of the respective mesh element within said first-mesh grid-based control volume region; impurity quantity calculation means for calculating a sum of impurity quantities corresponding to each grid point on said first mesh based on a total area of each mesh-based control volume surrounding the grid point and an impurity concentration at the grid point; impurity quantity setting means for initially setting, with respect to each mesh-based control volume, an impurity concentration of the mesh-based control volume by using an impurity concentration of each vertex of mesh elements on said first mesh which overlaps the mesh-based control volume, as well as determining an impurity concentration of each mesh-based control volume as a function of the initial set value of the impurity concentration multiplied by a conversion coefficient; impurity quantity comparison means for accumulating, based on an area of each mesh-based control volume connected to a grid point on said first mesh and the corresponding impurity concentration initially set by said impurity quantity setting means of a respective mesh-based control volume, impurity quantities corresponding to the grid point on said first mesh, as well as comparing a sum of impurity quantities calculated by said impurity quantity calculation means and said accumulated impurity quantities to obtain said conversion coefficient allowing the compared values to agree with each other; and impurity quantity transfer means for calculating, with respect to each mesh-based control volume, an area of an overlap region between said mesh-based control volume and said grid-based control volume region on said second mesh, and transferring an impurity quantity of said mesh-based control volume to said grid-based control volume region on said second mesh, according to the calculated area, to calculate an impurity quantity corresponding to each grid point on said second mesh.