Siemens Industry Software Gmbh

Mentor Graphics Corporation

Jakub Janicki

Szczepan Urban

Yu Jane Huang

Grzegorz Mrugalski

Janusz Rajski

Wu-Tung Cheng

Jerzy Tyszer

Nilanjan Mukherjee

Mark A Kassab

Manish Sharma

Huaxing Tang

Avijit Dutta

This application discloses a computing system implementing an automatic test pattern generation tool to perform scan chain diagnosis-driven compaction setting. The computing system can perform fault simulation on scan chains in a circuit design describing an integrated circuit, which loads test patterns to the simulated scan chains and unloads test responses from the simulated scan chains. The computing system can determine locations of sensitive bits and locations of unknown bits in each of the scan chains based on the test responses from the simulated scan chains, and generate a configuration for a compactor in the integrated circuit based, at least in part, on the locations of the sensitive bits and the locations of the unknown bits in each of the scan chains, wherein the compactor is configured to compact test responses from the scan chains in the integrated circuit based on the configuration.

Suspect resolution for scan chain defect diagnosis

Various aspects of the disclosed technology relate to predicting physical failure analysis-oriented diagnosis resolution. Fault simulation is performed on a circuit design to derive test responses for a set of faults and test patterns for testing circuits fabricated according to the circuit design. The set of faults is grouped into groups of equivalent faults based on the test responses. A group of equivalent faults consists of faults having the same test responses for all test patterns in the test patterns that can activate the faults. A PFA (physical failure analysis)-oriented diagnosis resolution evaluation value is computed by averaging weighted sizes of the groups of equivalent faults. The weight factors for the groups of equivalent faults with sizes greater than a certain number being smaller than the weight factors for rest of the groups of equivalent faults.

Physical failure analysis-oriented diagnosis resolution prediction

A circuit comprises a scan chain comprising one or more multi-bit flip-flops, a plurality of multiplexers, and new scan enable signal generation circuitry. Each of the plurality of multiplexers is associated with a particular bit of the one or more multi-bit flip-flops with an output of the each of the plurality of multiplexers coupled to a data input of the particular bit, which is configured to select, based on a scan direction control signal, between an input signal from functional circuitry of the circuit and an input signal from a data output of a bit of the scan chain immediately following the particular bit in a normal scan shift direction. The new scan enable signal generation circuitry is configured to generate a new scan enable signal for the one or more multi-bit flip-flops based on the scan direction control signal and a scan enable signal for the scan chain.

Reversible multi-bit scan cell-based scan chains for improving chain diagnostic resolution

This application discloses a computing system implementing an automatic test pattern generation tool can generate test patterns to apply to a reversible scan chain in an integrated circuit. The reversible scan chain can be configured to serially load and unload the test patterns in multiple directions to generate test responses. The computing system can implement a defect diagnosis tool to detect a presence of a suspected defect associated with the reversible scan chain based on the test responses, identify which of the multiple directions used to load and unload the test patterns corresponds to the suspected defect in the reversible scan chain based on the test responses, and determine a portion of the integrated circuit to inspect for a manufacturing fault corresponding to the suspected defect based, at least in part, on the identification of which of the multiple directions corresponds to the suspected defect in the reversible scan chain.

Diagnostic resolution enhancement with reversible scan chains

This application discloses a computing system implementing an automatic test pattern generation tool to generate test patterns to apply to scan chains in an integrated circuit. The computing system can implement a defect diagnosis tool to simulate a circuit design describing an integrated circuit, inject faults from a fault list into the simulated circuit design, and apply the test patterns to the simulated circuit design. The computing system implementing the defect diagnosis tool can determine fault responses to the test patterns read from the simulated circuit design, which indicate a detection of the faults injected in the simulated circuit design, compress, for each of the faults in the fault list, the fault responses into fault signatures, consolidate the faults from the fault list into fault groups based on the fault signatures, and estimate a diagnosis resolution for the integrated circuit based, at least in part, on the fault groups.

Diagnosis resolution prediction

Disclosed are representative embodiments of methods, apparatus, and systems for test scheduling and test access in a test compression environment. Clusters of test patterns for testing a plurality of cores in a circuit are formed based on test information that includes compressed test data, corresponding tester channel requirements and correlated cores. The formation of test pattern clusters is followed by tester channel allocation. A best-fit scheme or a balanced-fit scheme may be employed to generate channel allocation information. A test access circuit for dynamic channel allocation can be designed based on the channel allocation information.

Test scheduling and test access in test compression environment

Systems and methods for re-ordering test patterns for circuit design or testing. A method includes receiving a set of scan chains and associated test patterns, and computing a penalty score for each test pattern in the set of test patterns. The method includes selecting a first pattern of the set of test patterns that has a lowest computed penalty score in the set of test patterns, and removing the first pattern from the set of test patterns and adding the first pattern to a set of ordered patterns. The method includes, for each remaining test pattern, computing an accumulated penalty score for each remaining pattern, selecting a next pattern of the set of test patterns that has a lowest accumulated penalty score in the set of test patterns, removing the next pattern from the set of test patterns, and adding the next pattern to the set of ordered patterns.

Non-adaptive pattern reordering to improve scan chain diagnostic resolution in circuit design and manufacture

Disclosed are representative embodiments of methods, apparatus, and systems for test scheduling for testing a plurality of cores in a system on circuit. Test data are encoded to derive compressed test patterns that require small numbers of core input channels. Core input/output channel requirement information for each of the compressed test patterns is determined accordingly. The compressed patterns are grouped into test pattern classes. The formation of the test pattern classes is followed by allocation circuit input and output channels and test application time slots that may comprise merging complementary test pattern classes into clusters that can work with a particular test access mechanism. The test access mechanism may be designed independent of the test data.

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Poznan, Poland

Jakub Janicki