Deep Clustering and Regression Ensemble Network for Lot Cycle Time Prediction in Semiconductor Wafer Fabrication

Abstract

Accurate cycle time (CT) prediction is crucial in semiconductor manufacturing. Hybrid models integrating classification and prediction models can enhance CT prediction accuracy. However, existing methods have limitations, including challenges in capturing the dynamic conditions of the production line and optimizing job classification to ensure high CT prediction performance. In this study, we propose a novel hybrid framework for predicting process step-level CT in semiconductor wafer fabrication, thereby addressing the limitations of previous methods. Moreover, the paper formalizes and introduces dynamically changing manufacturing environment attributes as variables that contribute to CT. The proposed method combines deep embedded clustering (DEC) with a regression ensemble network. First, the DEC extracts cluster-friendly representative features from high-dimensional CT datasets and classifies jobs accordingly. Then, a weighted ensemble approach merges regression networks based on cluster membership probabilities. Unlike existing methods that separately handle feature extraction, job classification, and CT prediction, the proposed unified network synchronizes these processes. Experimental results using real-world operational data from a semiconductor manufacturing system indicate that the proposed prediction method considerably outperforms previous approaches in terms of prediction accuracy. To the best of our knowledge, this is the first study to integrate deep clustering with a regression ensemble network for predicting cycle time at the process step level in semiconductor manufacturing. By synchronizing feature extraction, clustering, and prediction tasks, the proposed framework achieves enhanced accuracy and robustness in dynamically changing manufacturing environments.