Using Weighted Scan Enable Signals to Improve Test Effectiveness of Scan-Based BIST
Using Weighted Scan Enable Signals to Improve Test Effectiveness of Scan-Based BIST
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DOI：
10.1109/tc.2007.70767
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发表时间：
2007-12
影响因子：
3.7
通讯作者：
D. Xiang;Mingjing Chen;H. Fujiwara
中科院分区：
文献类型：
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作者：
D. Xiang;Mingjing Chen;H. Fujiwara
常规的每扫描内置的自我测试（BIST）方案需要多个换档周期，然后需要一个捕获周期。扫描触发器收到的故障效应在下一个测试向量（如扫描测试）中移动时会移出。与确定性测试不同，不必在扫描链中应用完整的测试矢量。通过正确控制扫描链的扫描信号，提出了一种新的基于扫描的BIST方案。在单独的扫描链中，将不同的加权值分配给扫描信号。如有必要，可以在任何时钟周期插入捕获周期。提出了根据建议的测试方案进行的新可检验性估计程序。提出了一个贪婪的程序，以选择每个扫描链的重量。实验结果表明，所提出的方法可以大大提高基于扫描的靠背的测试有效性，并且大多数电路都可以获得完全的故障覆盖范围或非常接近完全故障覆盖率。
The conventional test-per-scan built-in self-test (BIST) scheme needs a number of shift cycles followed by one capture cycle. Fault effects received by the scan flip-flops are shifted out while shifting in the next test vector, like scan testing. Unlike deterministic testing, it is unnecessary to apply a complete test vector to the scan chains. A new scan-based BIST scheme is proposed by properly controlling the scan enable signals of the scan chains. Different weighted values are assigned to the scan enable signals of scan flip-flops in separate scan chains. Capture cycles can be inserted at any clock cycle if necessary. A new testability estimation procedure according to the proposed testing scheme is presented. A greedy procedure is proposed to select a weight for each scan chain. Experimental results show that the proposed method can improve test effectiveness of scan-based BIST greatly and most circuits can obtain complete fault coverage or very close to complete fault coverage.