A Software-based Scan Chain Diagnosis for Double Faults in A Scan Chain
Hyeonchan Lim, Seokjun Jang, Sungho Kang · 2018
This paper presents a simulation-based scan chain diagnosis algorithm for double faults in a scan chain. With an ordinary flush test pattern, only the last fault can be observed while the others are masked by the last fault. Considering the multiple faults, the forward fault and the rearward fault are decided by analyzing signatures of a faulty chain and good chains, separately. The results of analysis are upper bound (rearward fault) and lower bound (forward fault). If only one fault exists, there is only a candidate in the boundary. The proposed technique can be applied for both stuck-at and transition faults. ISCAS'89 benchmark circuits verify the proposed method and the experimental results show that the diagnosis resolution is increased compared to the conventional method.