Fault Clustering Technique for 3D Memory BISR

Tianjian Li1,a, Yan Han1,b, Xiaoyao Liang1,c, Hsien-Hsin S. Lee2 and Li Jiang1,d
1Department of Computer Science & Engineering, Shanghai Jiao Tong University.
2Taiwan Semiconductor Manufacturing Company, Ltd.


Three Dimensional (3D) memory has gained a great momentum because of its large storage capacity, bandwidth and etc. A critical challenge for 3D memory is the significant yield loss due to the disruptive integration process: any memory die that cannot be successfully repaired leads to the failure of the whole stack. The repair ratio of each die must be as high as possible to guarantee the overall yield. Existing memory repair methods, however, follow the traditional way of using redundancies: a redundant row/column replaces a row/column containing few or even one faulty cell. We propose a novel technique specifically in 3D memory that can overcome this limitation. It can cluster faulty cells across layers to the same row/column in the same memory array so that each redundant row/column can repair more ``faults''. Moreover, it can be applied to the existing repair algorithms. We design the BIST and BISR modules to implement the proposed repair technique. Experimental results show more than 71% enhancement of the repair ratio over the global 3D GESP solution and 80% redundancy-cost reduction, respectively.

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