Estimating the Job Cycle Time in Wafer Fabrication with Distributed Sensors

Estimating the job cycle time is very important for the control of a factory. However, the uncertainty in the job cycle time is not easy to deal with. In order to effectively estimate the job cycle time in a wafer fabrication factory, a group of distributed sensors are used in this study. In the proposed methodology, each sensor monitors the factory conditions, and uses a fuzzy neural network to estimate the job cycle time, based on its local observation. Each sensor communicates its view and estimates to other sensors with the aid of the central control unit. According to the experimental results, the aggregate estimation performance was considerably improved through the sensors’ collaboration.