Pair-Grouping Scan Chain Architecture for Multiple Scan Cell Fault Diagnosis

Abstract

The need for scan chain diagnosis is increased because the normal operation of scan chain is prioritized to ensure reliability of the scan test results that performed on most circuits. For most scan architectures, only single stuck-at fault can be diagnosed. Even if multiple fault diagnosis is possible, it does not show good resolution. In this paper, a new scan chain architecture with pair-grouping is proposed which enables multiple stuck-at fault diagnosis with higher diagnostic resolution. An ideal diagnostic resolution is shown in a scan group if at least one normal scan chain exists in paired scan group. The experimental result shows that the diagnostic performance only relates to scan group size, which represents a great advantage in the large circuit.