Synopsys addresses FinFET defects, embedded-flash test at ITC

Synopsys chose the International Test Conference to highlight two significant initiatives: defect-detection enhancements in TetraMAX ATPG through slack-based cell-aware test capability, and a new STAR (self-test and repair) Memory System for embedded flash. 

The TetraMAX enhancements target subtle defects, including ones in FinFETs, and it achieves automotive-standard quality levels. The new STAR system offers high test coverage and in-field diagnostics, reduces test cost and integration effort, and is available now for UMC 55-nm eFlash technology. Robert Ruiz, senior product marketing manager, said the new capabilities complement Synopsys’s design and silicon product portfolio for mobile, networking, automotive, digital-home, implantable-medical, and Internet of Things applications.

Ruiz traced the evolution of TetraMAXo ATPG from stuck-at fault detection to slack-based and cell-aware techniques. He cited defects occurring today, including metal shorts, open vias, FinFET opens, and litho violations, echoing comments from Synopsys chairman and co-CEO Aart de Geus during his Tuesday keynote address. Ruiz said more than 50% of failures are not found with standard at-speed tests, with defects tested on short paths not detected. In addition, the majority of defects occurring inside library cells are not stimulated during test and are therefore not observed.

Overcoming these limitations, he said, requires the combined fault-model approach in the new TetraMAX slack-based cell-aware ATPG. The cell-aware portion sensitizes potential defects within a cell at the cell input, and the slack-based portion ensures that cell defects are tested on long paths. He elaborated, noting that a 30-ps delay defect will not be detected within a path having 50-ps slack, but it will be on a path having only 10-ps slack.

He said the enabling technologies for slack-based cell-aware test include StarRC extraction, HSPICE CircuitSim simulation, and PrimeTime timing analysis tools from Synospys. He said that initial results show that the slack-based cell-aware approach provides higher detection of small, transient faults within cells—raising coverage significantly with few additional test patterns.

Savita Banerjee, senior product marketing manager, described the DesignWare STAR Memory System as now offering the industry’s first commercial BIST solution for embedded flash, which is increasingly deployed in automotive, wearable, IoT, and other applications.

Testing embedded flash externally requires expensive test equipment and long test times, she said. The new STAR system, she said, offers a simple IEEE 1149.1 standard tester interface and provides on-ship pattern generation to cut embedded-flash test costs by 20%. It also enables fast silicon bring-up and debug, she added, and for automotive applications it enables in-field diagnostics in accordance with ISO 26262.

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