Modeling and simulation of a Petri nets-based diffusion cell controller in an IC CIM system

We develop a systematic approach to analyze, model and simulate the diffusion cell controller (C/C) in a computer integrated manufacturing (CIM) system of an integrated circuit (IC) wafer by using Petri net theorem. A good C/C has the ability to handle and diagnose the complex procedures in the hybrid and dynamic system of IC production. First we use the IDEF0 method for the system specification analysis that makes us classify the procedures of IC production, and understand the resource sharing situation and the production control logic. Then the generalized stochastic Petri net (GSPN) is applied to model the system of a diffusion cell in IC CIM, which is a useful tool to model and analyze a discrete event dynamic system (DEDS). Based on this Petri net model, we can perform the system's qualitative and quantitative analyses. The model has been validated by comparing the simulation data with the real data. Also, we can find out the bottleneck of the cell and answer lots of "what-if" questions by doing sensitivity analyses. Here, we make some predictions for the system performance improvement based on the existing capacity.