A Hilbert curve-based delay fault characterization method for FPGAs

With the increasing process variations in advanced technologies, delay faults pose a significant issue in FPGAs. In manufacturing testing, it becomes important to quickly and accurately locate the delay defect area. Conventional delay testing methods do not take into account the spatial information of process variation induced delay faults, thus cannot accurately limit the delay defects to a well restricted area. Based on the superb locality preserving feature of space-filling curves, we develop a method to locate delay faults in much finer resolution. The method uses a Hilbert curve to guide the test configuration of FPGAs. Depending on the number of observation points inserted to the curve, different levels of locating resolution can be achieved. Compared with normal curves, our method obtained around 60% increase in delay faults locating resolution.