Fast Temperature Control in Semiconductor Vertical Furnace with Time-Optimal Control and Iterative Experiments

The semiconductor manufacturing industry continues to develop to meet the demand of semiconductor devices. Among various processes during manufacturing semiconductor devices, the oxidation and layer deposition process conducted by semiconductor vertical furnace is known to be economic, yet due to its large size, has a relatively long process time. To raise the productivity rate of the semiconductor vertical furnace, faster and high-precision properties in the temperature control are needed simultaneously. However, the presence of nonlinearity from radiation heat transfer in the semiconductor vertical furnace caused the coexistence of fast and high-precision control by model-based approach to be more challenging. Therefore, the aim of this paper is to achieve faster temperature control in the semiconductor vertical furnace while maintaining its precision by introducing a data-based approach in the time-optimal control framework. The data-based approach is implemented as an iterative process of model recalculation based on experimental results. Experiments with full-scale semiconductor vertical furnace verified that the proposed method was able to raise the temperature accurately from 300°C to 400°C in less than 10 minutes.