A New, Computationally Efficient “Blech Criterion” for Immortality in General Interconnects

Traditional methodologies for analyzing electromigration (EM) in VLSI circuits first filter immortal wires using Blech’s criterion, and then perform detailed EM analysis on the remaining wires. However, Blech’s criterion was designed for two-terminal wires and does not extend to general structures. This paper demonstrates a first-principles-based solution technique for determining the steady-state stress at all the nodes of a general interconnect structure, and develops an immortality test whose complexity is linear in the number of edges of an interconnect structure. The proposed model is applied to a variety of structures. The method is shown to match well with results from numerical solvers, to be scalable to large structures.