一种测试SRAM失效的新型March算法

Novel March Sequence for Testing Process Variation Induced Failures

随着工艺偏差的日益增加,新的失效机制也在亚100 nm工艺的CMOS电路里出现了,特别是SRAM单元。SRAM单元的故障由晶体管阈值电压Vt差异引起,而Vt差异又是由工艺偏差造成的。对于这类SRAM失效机制,需要把它映射成逻辑故障模型,并为检测出这类故障研究出新的March测试序列。针对这些逻辑故障模型,提出了一种新型的March算法序列;并通过验证,得到了很高的测试覆盖率。

With increasing process variations in process technologies, new failure mechanisms are emerging in CMOS circuits, especially SRAM cells. The source of the failure mechanisms in SRAM is the threshold variation of transistors （Vt）, which results from process variations. For detecting those SRAM failures, it＇s necessary to map them to logic fault models and develop a new March test sequence to address the emerging failure mechanisms with minimal overhead on test time. A new March test sequence is proposed for these logic fault models and high test coverage is obtained.