Abstract: A failure diagnostic apparatus includes a path calculation unit which calculates, for each input pattern to a diagnosis target cell, a path affecting an output value of the diagnosis target cell when a failure is assumed as an activation path, a path classification unit which classifies the activation path associated with the input pattern for which the diagnosis target cell has passed a test and the activation path associated with the input pattern for which the diagnosis target cell has failed the test, a path narrowing unit which calculates a first failure candidate path, a second failure candidate path and a normal path of the diagnosis target cell based on classified activation paths, and a result output unit which outputs information on the first failure candidate path, the second failure candidate path and the normal path.

Abstract: A failure diagnostic apparatus includes a path calculation unit which calculates, for each input pattern to a diagnosis target cell, a path affecting an output value of the diagnosis target cell when a failure is assumed as an activation path, a path classification unit which classifies the activation path associated with the input pattern for which the diagnosis target cell has passed a test and the activation path associated with the input pattern for which the diagnosis target cell has failed the test, a path narrowing unit which calculates a first failure candidate path, a second failure candidate path and a normal path of the diagnosis target cell based on classified activation paths, and a result output unit which outputs information on the first failure candidate path, the second failure candidate path and the normal path.

Abstract: A fault location estimation device includes: a faulty scan chain identification unit that identifies a faulty scan chain and its fault type based on result of operation verification test; a faulty scan FF narrowing unit that compares test result of the faulty scan chain with simulation result for determining a faulty scan FF range beginning at the location of a scan FF where both results differ; and a path trace narrowing unit that references logic circuit configuration information, signal line expected value, a failure-observed scan FF, and test result of a defective circuit to extract a scan FF on the faulty scan chain, which may be reached from a failure-observed scan FF observed on a normal scan chain by tracing back a failure propagation path while performing implication procedure for an input side, and thereby further narrows the faulty scan FF range determined by the faulty scan FF narrowing unit.

Abstract: A fault location estimation device includes: a faulty scan chain identification unit that identifies a faulty scan chain and its fault type based on result of operation verification test; a faulty scan FF narrowing unit that compares test result of the faulty scan chain with simulation result for determining a faulty scan FF range beginning at the location of a scan FF where both results differ; and a path trace narrowing unit that references logic circuit configuration information, signal line expected value, a failure-observed scan FF, and test result of a defective circuit to extract a scan FF on the faulty scan chain, which may be reached from a failure-observed scan FF observed on a normal scan chain by tracing back a failure propagation path while performing implication procedure for an input side, and thereby further narrows the faulty scan FF range determined by the faulty scan FF narrowing unit.

Abstract: A fault location estimation system includes single-fault-assumed diagnostic unit nodes; error-observation node basis candidate classification unit; inclusion fault candidate group selection unit; inter-pattern overlapping unit; and multiple-fault simulation checking unit.

Abstract: A fault location estimation system comprises single-fault-assumed diagnostic means that assumes a single fault and stores fault candidates, fault types, and detected error-observation nodes at which an error arrives from the fault candidates; error-observation node basis candidate classification means that classifies error propagating fault candidates into groups according to error-observation nodes using the fault candidates and the error-observation nodes and stores the groups as fault candidate groups; inclusion fault candidate group selection means that acquires a relation between each fault candidate group and a fault output, calculates an inclusion relation among the fault candidate groups, and, if path information on one fault candidate group includes path information on another fault candidate group, deletes the inclusion fault candidate group; inter-pattern overlapping means that calculates combinations of fault candidate groups that can reproduce a test result in all test patterns by referencing the