Browsing by Subject "Lithography modeling"
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Item Design for manufacturability and reliability through learning and optimization(2020-05-08) Ye, Wei, Ph. D.; Pan, David Z.; Sun, Nan; Touba, Nur A.; Liu, Qiang; Zeng, Zhiyu (Albert)Modern society relies on technologies with integrated circuits (ICs) at their heart. In the last several decades, as the performance and complexity of ICs keep escalating, the semiconductor industry has demonstrated an ability to develop new process techniques and product designs that are both manufacturable and reliable. However, as the transistor feature size is further shrunk into extreme scaling (e.g., 10 nm and beyond), large scale integration of transistors and interconnects brings ever-increasing challenges revolving around manufacturability and reliability. The major issues in manufacturability and reliability for modern ICs come from three aspects: (1) layout-dependent manufacturability (e.g., manufacturing yield sensitive to design patterns); (2) time-consuming process modeling (e.g., complex lithography systems); (3) design-sensitive reliability (e.g., lifetime related to layout designs). In order to close the gap between design and manufacturing and enhance design reliability, automated layout generation requires cross-layer information feed-forward and feedback, such as accurate process modeling and reliability-guided design optimization. This dissertation attempts to address the aforementioned challenges in manufacturing closure and reliability signoff through efficient machine learning techniques for lithography hotspot detection and lithography modeling, and synergistic design optimization for electromigration (EM). Our research includes efficient lithography hotspot detection, learning-based lithography modeling, and EM-aware physical design to achieve efficient manufacturing closure and reliability signoff. For lithography hotspot detection, due to the increasingly complicated design patterns, early and quick feedback for lithography hotspots is desired to guide design closure in early stages. Machine learning approaches have been successfully applied to hotspot detection while demonstrating a remarkable capability of generalization to unseen hotspot patterns. However, most of the proposed machine learning approaches are not yet able to answer two critical questions: model confidence and model efficiency. This study develops a lithography hotspot detection framework capable of providing modeling confidence with fewer training data and fewer expensive lithography simulations needed, and also provides a holistic measure for the intrinsic class imbalance in lithography hotspot detection. For lithography modeling, one of the major limitations in process modeling is considered: the trade-off between modeling efficiency and accuracy. The steady decrease of the feature sizes, along with the growing complexity and variation of the manufacturing process, has tremendously increased the lithography modeling complexity and prolonged the already-slow simulation procedure. Different modeling frameworks are proposed in this study, leveraging recent advancements in machine learning, particularly generative adversarial learning, to generate virtually simulated silicon image efficiently without running detailed optical simulations. With our proposed deep learning techniques, a significant improvement in modeling efficiency is achieved while maintaining high modeling accuracy. For EM-aware physical design, we demonstrate the limitation of conventional design and EM signoff flow when faced with the ever-growing EM violations in advanced technology nodes. Two essential directions are explored with practical algorithms and new design flows: (1) Power grid EM detection and optimization with several detailed placement techniques; (2) Learning-based signal EM prediction and mitigation at different physical design stages. The effectiveness of proposed design optimization and machine learning techniques is demonstrated with extensive experiments on industrial-strength benchmarks. Our approaches are capable of reducing turn-around time, saving modeling costs, and enabling fast manufacturing closure and reliability signoff.