Structural Test Generation for AI Accelerators using Neural Twins

We present a neural twin-based structural test pattern generation method for stuck-at faults in systolic array-based AI inferencing accelerators. The neural twin is a neural representation of the gate-level netlist of a processing element and it provides a one-to-one topological correspondence with the PE netlist. We leverage neural twin-enabled backpropagation for gradient computation to determine an input pattern that sensitizes a fault in the netlist. Our framework also supports pattern compaction for a batch of faults. Consequently, GPU-accelerated test-pattern generation is achieved with the proposed framework that can potentially detect hard-to-detect and random-pattern-resistant faults in AI accelerators. Experimental results for 4-bit, 8-bit, and 16-bit fixed-point accelerator arrays show the effectiveness of the proposed method.