A Metal-Via Resistance Based Physically Unclonable Function with 1.18% Native Instability
Beomsoo Park, Mark Mohammad Tehranipoor, Domenic J. Forte, Nima Maghari · 2019
A physically unclonable function (PUF) leveraging the parasitic resistance created by the metal-via interconnection as entropy source is proposed in this paper. Metals 2 through 6 of a 65nm process is used to create the necessary parasitic resistance. Instead of using additional stabilization techniques, an incremental analog-to-digital converter is implemented to precisely measure the voltage difference between two branches consisting of the metal-via interconnection based parasitic resistances. The fabricated PUF, without using any post processing algorithm, achieves a native instability of 1.18% with 1000 repeated evaluations. The worst-case instability for voltage and temperature ranging from 0.8V to 1.3V and 0°C to 85°C, respectively is below 2.5%. The distance ratio between intra-die and inter-die Hamming Distance is above 310X.