Runtime Stress Estimation for Three-dimensional IC Reliability Management Using Artificial Neural Network

摘要

Heat dissipation and the related thermal-mechanical stress problems are the major obstacles in the development of the three-dimensional integrated circuit (3D IC). Reliability management techniques can be used to alleviate such problems and enhance the reliability of 3D IC. However, it is difficult to obtain the time-varying stress information at runtime, which limits the effectiveness of the reliability management. In this article, we propose a fast stress estimation method for runtime reliability management using artificial neural network (ANN). The new method builds ANN-based stress model by training offline using temperature and stress data. The ANN stress model is then used to estimate the important stress information, such as the maximum stress around each TSV, for reliability management at runtime. Since there are a variety of potential ANN structures to choose from for the ANN stress model, we analyze and test three ANN-based stress models with three major types of ANNs in this work: the normal ANN-based stress model, the ANN stress model with hand-crafted feature extraction, and the convolutional neural network-(CNN) based stress model. The structures of each ANN stress model and the functions of these structures in 3D IC stress estimation are demonstrated and explained. The new runtime stress estimation method is tested using the three ANN stress models with different layer configurations. Experiments show that the new method is able to estimate important stress information at extremely fast speed with good accuracy for runtime 3D IC reliability enhancement. Although all three ANN stress models show acceptable capabilities in runtime stress estimation, the CNN-based stress model achieves the best performance considering both stress estimation accuracy and computing overhead. Comparison with traditional method reveals that the new ANN-based stress estimation method is much more accurate with a slightly larger but still very small computing overhead.