HYBRID CASCADE MODEL BASED PREDICTIVE CONTROL SYSTEM, ESPECIALLY WITHOUT EXCESSIVE CALCULATION

摘要

PROBLEM TO BE SOLVED: To provide a control system comprising thermal processing equipment of semiconductor substrates, such as a hybrid cascade MBPC (Model-Based Predictive Control) for a vertical thermal reactor and conventional control system.;SOLUTION: In order to achieve effective dynamic linear models, a target temperature control range is divided into a plurality of temperature sub-ranges. For every temperature sub-range, and for every heating zone, a corresponding dynamic model is identified. During temperature ramp up/down, the control system is provided with a fuzzy control logic and inference engine for automatically switching the dynamic models according to the actual temperature. When thermocouple (TC) temperature measurement fails, a software soft sensor based on dynamic model computing is used to replace an actual TC sampling in a fixed position for a control system input. Consequently, when a TC failure occurs during a process, the process can be completed without loss of the semiconductor substrate being processed.;COPYRIGHT: (C)2004,JPO