MML researchers, in collaboration with the University of New Mexico, recently applied a new reliability modeling approach, peridynamics, to the problem of electromigration in microelectronic interconnects, which are found in nearly all today’s electronics, including computers, cell phones, and digital cameras. Electromigration is a major failure mode of microelectronic interconnects. In this process, voids are created when atoms in the conducting material are dislodged by momentum transfer from the electron current running through it. These voids can collect to sever microcircuits, resulting in device failure. In order to avoid this effect, microelectronic chip designers seek accurate mathematical models of the electromigration process, which they can use in conjunction with physical tests, to ensure the reliability of the nearly 2000 meters of circuitry in a typical device.
The peridynamics modeling method, originally developed by Sandia National Laboratories for modeling fracture, offers advantages over other mathematical modeling methods such as finite element analysis, which cannot easily capture the spontaneous formation cracks and voids. Electromigration void formation is especially difficult to model because it results from the interaction of four different physical processes: electrical current, heat flow, atom migration, and mechanical deformation and stress. Using a 1-dimensional model, this research has demonstrated that the electrical current, as well as flows of heat and atoms, can be successfully incorporated into the peridynamic approach to model electromigration phenomena.
A detailed description of this modeling approach was recently published: W. Gerstle, S. Silling, D. Read, V. Tewary, and R. Lehoucq, “Peridynamic Simulation of Electromigration,” CMC: Computers, Materials & Continua, Vol. 8, No. 2, pp. 75-92, October, 2008.