Modeling for Sensor-Based Semiconductor Process Control

Modeling of semiconductor equipment is a prerequisite for advanced sensor-based real-time process control. Models for control design differ from those used for studying the detailed physics of these systems. Integrated Systems, Inc. (ISI) proposes to investigate several different modeling approaches for control system design of semiconductor processes and develop a software modeling tool. We propose to apply the techniques to a Rapid Thermal Processing (RTP) process. RTP is a state-of-the-art method for performing several important steps in semiconductor wafer fabrication. A physically-based model of the process will be derived using a method for modeling ther thermal process as a nonlinear passive network. The model will be linearized for control design. A standard input-output model will also be derived as a baseline. In Phase I, models will be developed and evaluated in a computer simulation. In Phase II, a set of comprehensive models and associated software will be developed and demonstrated on a new commercial RTP chamber. The chamber will be used to evaluate and compare the various models. Use of the models promises to yield significant improvements in process control performance (temperature uniformity, repeatability) compared to the existing methods.