DfT optimization for pre-bond testing of 3D-SICs containing TSVs

This paper proposes to provide testability for the breaking point produced by the Through-Silicon-Vias (TSVs) of 3D-Stacked ICs (3D-SICs) during pre-bond testing with low Design-for-Testability (DfT) cost. Different from prior solutions which utilize two additional wrapper cells for the breaking point at each TSV, this paper proposes to provide the testability of two ends of the TSVs respectively by reusing the existing Primary-Inputs (PIs)/ Primary-Outputs (POs) and Pseudo-PIs/Pseudo- POs (PPIs/PPOs). To further reduce the hardware overhead and enhance the efficiency of the proposed method, this paper has also proposed the metrics and algorithm on deciding the selecting order of the TSVs and the PIs/PPIs (POs/PPOs) to be reused. The experimental results on larger ITC´99 benchmark circuits validate the effectiveness of the proposed method.