Abstract: Physical unclonable function (PUF) is a novel method to extract "secret" from complex physical systems.It is expected to be widely used in many fields such as mobile device authentication, key generation and storage.But existing silicon PUF circuits consider only on-chip logic device delay and ignore global interconnect delay that has already become the dominant factor of timing model, thus behaving differently with corresponding physical circuits.In this paper, a new silicon PUF circuit is proposed by considering state-of-the-art IC manufacturing process variations and incorporating global interconnect delay model into PUF building.Experiments are conducted on Synopsys Hspice C-2010 analog design platform, on which PUF circuits' parameters of inter-chip and intra-chip variations are measured for evaluating the performance of a 128-bit PUF.Experiment results show that this PUF circuit is effective and is expected to support applications of identity authentication in mobile computing and of protecting core chips from intrusive attack.