Collecting diagnostic information through dichotomic search from Logic BIST of failing in-field automotive SoCs with delay faults

Embedded nano-electronic devices have spread in daily life over the past ten years. Chip and embedded system manufacturing has thus become more challenging in recent years.When safety-critical sectors like the automobile are considered, addressing system anomalies and faults is crucial. Therefore, it is necessary to develop and research innovative ways to maintain high reliability in safety-critical sectors despite the complexity of present Systems-on-Chip (SoCs).In order to ensure high reliability, and be compliant with reliability standards, designers started to add additional circuitry to perform on-device tests. Built-In-Self-Test (BIST) is a technology that allows to conduct exhaustive tests within devices and, most importantly, without the need for external equipment. BIST can detect faults by outputting a signature at test end, which can be compared with a known value. Thus such known signatures are key, and in case of a signature mismatch it is not trivial to understand the root cause of the failure.This paper proposes a methodology to find the first failing pattern which causes the BIST’s signature to deviate and a way to collect good signatures from in-field devices, at key on/off, where BISTs are programmed and executed by the firmware at maximum frequency for an industrial case study produced by STMicroelectronics.The transition delay fault model is the primary target for the described work.