Development of a bridge fault extractor tool

Bridge fault extractors are tools that analyze chip layouts and produce a realistic list of bridging faults within that chip. FedEx, previously developed at Texas A&M University, extracts all two-node intralayer bridges of any given chip layout and optionally extracts all two-node interlayer bridges. The goal of this thesis was to further develop this tool. The primary goal was to speed it up so that it can handle large industrial designs in a reasonable amount of time. A second goal was to develop a graphical user interface (GUI) for this tool which aids in more effectively visualizing the bridge faults across the chip. The final aim of this thesis was to perform FedEx output analysis to understand the nature of the defects, such as variation of critical area (the area where the presence of a defect can cause a fault) as a function of layer as well as defect size

Ultra Reliable Computing Systems

For high security and safety applications as well as general purpose applications, it is necessary to have ultra reliable computing systems. This dissertation describes our system of self-testable and self-repairable digital devices, especially, EPLDs (Electrically Programmable Logic Devices). In addition to significantly improving the reliability of digital systems, our self-healing and re-configurable system design with added repair capability can also provide higher yields, lower testing costs, and faster time-to-market for the semiconductor industry. The digital system in our approach is composed of blocks, which realize combinational and sequential circuits using GALs (Generic Array Logic Devices). We describe three techniques for fault-locating and fault-repairing in these devices. The methodology we used for evaluation of these methods and a comparison with devices that have no self-repair capability was simulation of the self-repair algorithms. Our simulations show that the lifetime for a GAL-based EPLD that uses our multiple self-repairing methods is longer than the lifetime of a GAL-based EPLD that uses a single self-repair method or no self-repair method. Specifically, our work demonstrates that the lifetime of a GAL can be increased by adding extra columns in the AND array of a GAL and extra output ORs in a GAL. It also gives information on how many extra columns and extra ORs a GAL needs and which self-repairing method should be used to guarantee a given lifetime. Thus, we can estimate an ideal point, where the maximum reliability can be reached with the minimum cost