Method and apparatus for string model simulation of a physical semiconductor process including use of specific depth angles and segment list with removal of redundant segments

Abstract

A simulation method and a simulation apparatus suppress a parabolic increase in depth angle calculation time to a linear increase at most with respect to an increase in the number of depth angle calculation points on a surface string that represents a processing surface to be simulated. The simulation method and apparatus are applicable to a deposition process that deposits metal such as aluminum on a semiconductor substrate in a vacuum with the use of physical adsorption. The simulation method and apparatus are effective, in particular, to quickly calculate depth angles on a two-dimensional shape to a processing surface to which the deposition process is applied. The depth angles are angles in which particles fly toward the processing surface during the deposition process. The simulation method and apparatus trace a surface string representing the processing surface from the origin to the terminal thereof and find depth angles at all points on the surface string. If a supplement of adjacent segments on the surface string is negative, a depth angle at a node of the adjacent segments is calculated at once according to the supplement and a maximum or minimum angle already found at the preceding point. If a depth angle at a given point is not calculable based on the preceding point, a point that determines the depth angle is found in a segment list according to a bisection method.