Using Dummy Bridging Faults to Define Reduced Sets of Target Faults

To address the large numbers of bridging faults in a circuit, several approaches have been proposed for the selection of subsets of bridging faults as targets for test generation. A different approach that can be viewed as a fault collapsing method based on dominance relations between faults is investigated. It is enhanced by the introduction of dummy bridging faults, which are not real faults but whose tests detect large numbers of real faults. This approach is applied to nonfeedback four-way bridging faults. When no approximations are made, the proposed approach selects a subset of faults such that if they are detected all the nonfeedback four-way bridging faults are guaranteed to be detected. When this subset is too large, the proposed approach can also be applied to a subset of bridging faults preselected using other methods, e.g., realistic bridging faults or hard-to-detect bridging faults. In this case, it allows more bridging faults to be preselected. A new selection criterion and issues related to test generation for the selected faults are also investigated