Qualitative Simulation of Semiconductor Fabrication

As part of a larger effort aimed at providing symbolic, computer-aided tools for semiconductor fabrication experts, we have developed qualitative models of the operations performed during semiconductor manufacture. By qualitatively simulating a sequence of these modele we generate a description of how a wafer is affected by the operations. This description encodes the entire history of processing for the wafer and causally relates the attributes that describe the structures on the wafer to the processing operations responsible for creating those structures. These causal relationships can be used to support many reasoning tasks in the semiconductor fabrication domain, including synthesis of new recipes, and diagnosis of failures in operating fabrication lines.