WTM-Aware Shift Direction Selection for Low Power Bidirectional Scan Testing

초록

With the growing complexity of AI accelerators and high-performance SoCs, reducing power consumption during scan testing has become a critical challenge. This paper proposes a WTM-aware shift direction selection method for bidirectional scan architectures. The proposed method computes the Weighted Transition Metric (WTM) for both forward and reverse shift directions on each test pattern and scan chain and selects the direction yielding the lower WTM. Since the bit-reversed input produces identical flip-flop values regardless of direction, the original fault coverage is fully preserved. The direction selection is performed entirely offline in ATE software, requiring no additional hardware beyond the existing bidirectional scan infrastructure. Experimental results on ISCAS'89 benchmarks demonstrate average WTM reductions of 11-17% and peak WTM reductions of 10-15%. © 2026 IEEE.

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