A reference-based virtual metrology method for material removal rate prediction using convolutional neural network

The research of Virtual Metrology (VM) for Chemical Mechanical Planarization (CMP) process occupies an essential role in semiconductor manufacturing. This paper proposes a novel VM model to predict average Material Removal Rate (MRR) which is the crucial characteristic to indicate the productivity of CMP process. The proposed model is developed based on the integration of Convolutional Neural Network (CNN) and a reference-based feature extraction strategy, which is capable to combine the temporal knowledge, and the high complexity involved during CMP process. The proposed Reference-CNN model extracts temporal features by examining the sensor recordings to detect the changing trends, from which the references are created for further prediction. Afterwards, CNN models are constructed to interpret the comprehensive relations between data. The public datasets of 2016 Prognostics and Health Management (PHM) Data Challenge are used to evaluate model performance compared with the benchmarks selected from literature. Experimental results show that the proposed model is capable to output superior prediction accuracy.