A novel array-based test methodology for local process variation monitoring

As process technologies continually advance, local process variation has greatly increased and gradually become one of the most critical factors for IC manufacturing. To monitor local process variation, a large number of DUTs (device-under-test) in close proximity must be measured. In this paper, we present a novel array-based test structure to characterize local process variation with limited area overhead. The proposed test structure can guarantee high measurement accuracy by utilizing the proposed hardware IR compensation and voltage bias elevation. Furthermore, the DUT layout need not be modified for the proposed test structure so that the measured variation exactly reflects the reality in the manufacturing environment. The measured results from the few most advanced process-technology nodes demonstrate the effectiveness and efficiency of the proposed test structure in quantifying local process variation.