Cell Aware and stuck-open tests
Cell Aware and stuck-open tests
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Cell Aware 和卡住开路测试
DOI：
10.1109/ets.2016.7519316
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
A. Singh
中科院分区：
文献类型：
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作者：
A. Singh
近年来，细胞感知测试（CAT）受到了广泛的关注，有一些成功的案例报道了传统的卡滞和过渡延迟故障（TDF）测试所遗漏的缺陷。例如，在ITC 2012上，Hapke等人报告了32nm笔记本处理器部件的885 DPPM测试逃逸，尽管进行了工业强度卡滞和5检测TDF测试。据报道，对于已经经过严格“零缺陷”标准筛选的汽车零部件，电池感知测试也会产生显著的额外沉降物。重要的是，在实际的系统应用程序中，这些测试转义中的绝大多数被观察到会导致失败，这指出了一个严重的字段可靠性问题。这就提出了一些重要的问题：由细胞感知测试检测到的这些新缺陷是什么？为什么传统的粘滞测试和TDF测试忽略了它们？为什么这个问题直到最近才被发现？是否可以增强传统的单元无意识测试生成以检测这些故障？本教程介绍了对单元感知测试生成方法的详细研究，以回答这些问题。其目的不仅是分析和理解传统测试所遗漏的现代标准单元库中的缺陷，而且是这种新的测试方法唯一覆盖的，而且还包括这些测试逃避中哪些必须需要单元布局信息进行检测，以及哪些可以通过增强的卡滞和双模式测试生成以布局不知道的方式系统地定位。从单元感知测试中产生的大部分附加影响似乎来自主要针对开放缺陷的延迟模式。然而，即使使用CAT，扫描DFT的结构限制也会限制开放缺陷的可检测性。通常采用的LOC延迟测试不足以筛选所有能够产生错误电路输出的开放缺陷。我们表明，在系统级测试（SLT）中，甚至在用CAT筛选零件之后，危险激活的开放缺陷是至少一些被观察到的失败的可能原因。
Cell Aware testing (CAT) has received much publicity in recent years, with several reported success stories in screening defects missed by traditional stuck-at and transition delay fault (TDF) testing. For example, at ITC 2012, Hapke et al. reported 885 DPPM test escapes in a 32 nm notebook processor part despite industrial strength stuck-at and 5-detect TDF testing. Significant additional fallout from cell aware tests has also been reported for automotive parts already screened to stringent “zero-defect” standards. Importantly, the vast majority of these test escapes were observed to cause failure in actual system application, pointing to a serious field reliability issue. This raises some important questions: What are these new defects that are being detected by cell aware tests? Why are they missed by traditional stuck-at and TDF testing? Why has this problem only recently been discovered? Can traditional cell unaware test generation be enhanced to detect these faults? This tutorial presents a detailed study of the cell aware test generation methodology to answer these questions. The aim is not only to analyze and understand the defects in modern standard cell libraries missed by traditional tests that are uniquely covered by this new test approach, but also which of these test escapes necessarily need cell layout information for detection, and which can be systematically targeted in a layout unaware manner by enhanced stuck-at and two-pattern test generation. The large majority of the additional fallout from cell aware tests appears to be from the delay patterns that primarily target open defects. However, the structural limitations of scan DFT can limit the detectability of open defects even with CAT. Commonly employed LOC delay tests are not sufficient to screen all open defects capable of generating erroneous circuit outputs. We show that hazard activated open defects are the likely causes of at least some of the failures being observed in system level tests (SLT) even after parts are screened with CAT.