A new Physical Unclonable Functions based on measuring Power Distribution System resistance variations

Metal resistance variations in back-end-of-line processes can be significant, particularly during process bring-up. In this paper, I propose a simple method to measure resistance variations in the Power Distribution System (PDS) of an IC, and describe how these measurements can be applied to a Physical Unclonable Function (PUF). By applying a sequence of tests using small on-chip support circuits attached to the PDS, the resistance of components of the PDS can be obtained from the solution to a set of simultaneous equations, and be applied to hardware security by forming a PUF. We demonstrate that this PUF signature can then be used to uniquely identify each IC.