Abstract: An integrated circuit (IC) test engine generates N-cycle at-speed test patterns for testing for candidate faults and/or defects of a first set of transition faults and/or defects of an IC design. A diagnostics engine that receives test result data characterizing application of the N-cycle at-speed test patterns to a fabricated IC chip based on the IC design by an ATE, in which the test result data includes a set of miscompare values characterizing a difference between an expected result and a result measured by the ATE for a given N-cycle at-speed test pattern. The diagnostics engine employs a fault simulator to fault-simulate the N-cycle at-speed test patterns against a fault model that includes a first set of transition faults and/or defects and fault-simulate a subset of the N-cycle at-speed test patterns against a fault model that includes multicycle transition faults and/or defects utilizing sim-shifting.

Abstract: An apparatus and method for visualizing faults in a circuit design includes simulating faults for a circuit design in a layout and a schematic, editing the layout and schematic to include the simulated fault, and linking the layout and schematic with the fault simulation.

Abstract: A method for diagnosing failures within an integrated circuit where known diagnostic fault simulators are unable to detect failure mechanisms which do not conform to known failure models. Basic boolean equations are used to describe the internal nodes forming the logic. These equations are then evaluated by way of a good machine simulation to determine which of the equations are (most) true for failing test patterns and (most) false for passing patterns. At the end of the good machine simulation a score is calculated to determine the number of times (or percentage) for which the equation is true for failing patterns and false for passing patterns. The method is particularly effective for finding shorted nets pairs in which the failure mechanism does not fall within known models. The method described is instrumental in greatly reducing the time required for manual analysis of failure mechanisms not conforming to known models.

Abstract: A method to improve the testability and analysis of a hierarchical semiconductor chip design formed from a plurality of macros, each macro identifying a particular portion of a semiconductor chip design. This method includes providing a first macro netlist that identifies a logical description of a first portion of the semiconductor chip design and performing RPT analysis on the first macro netlist. The method also includes providing a second macro netlist identifying a logical description of a second portion of the semiconductor chip design and performing an RPT analysis on the second macro netlist. The first macro netlist is combined with the second macro netlist and an RPT analysis is performed on the combination of the first and second macro netlists.

Abstract: A method for diagnosing failures within an integrated circuit where known diagnostic fault simulators are unable to detect failure mechanisms which do not conform to known failure models. Basic boolean equations are used to describe the internal nodes forming the logic. These equations are then evaluated by way of a good machine simulation to determine which of the equations are (most) true for failing test patterns and (most) false for passing patterns. At the end of the good machine simulation a score is calculated to determine the number of times (or percentage) for which the equation is true for failing patterns and false for passing patterns. The method is particularly effective for finding shorted nets pairs in which the failure mechanism does not fall within known models. The method described is instrumental in greatly reducing the time required for manual analysis of failure mechanisms not conforming to known models.

Abstract: This invention teaches a system (10) and method for analyzing a fault within a model of a logic circuit. The method includes the computer executed steps of (a) building a fault model of the circuit model; (b) for each modelled fault that is determined to be untestable, (b) building a discrete node set comprised of nodes of the circuit model that are relevant to the untestable fault; and (c) outputting the discrete node set for analysis. The step of building a fault model includes a step of classifying the untestable faults into at least three categories including unobservable faults, excitation conflict faults, and reverse and forward implication (RFI) conflict faults. Faults from each of these three classifications are processed differently so as to build a relevant discrete node set for subsequent analysis.