Realistic modeling of electromigration in today’s ULSI interconnections.
Date of Issue2008
School of Electrical and Electronic Engineering
Systems on Silicon Manufacture Co. Pte. Ltd.
IC architecture makes extensively use of multiple interconnect levels with many vias that enable electrical current to flow between each level. A common failure mechanism in interconnections is the formation and the growth of voids and/or hillocks which may span across the line width and sever (or short) the electrical connections. The process of mass transportation is called Electromigration (EM). In contrast to a pure diffusion process due only to concentration gradients, the kinetic of EM in metal thin film is rather complicated and it is a mass transportation process controlled by various driving forces such as the electron wind, temperature gradients, stress gradients and the surface tension. Reliability evaluation and improvement of new interconnects require a more thorough understanding of the physics of EM, but experimental investigation can be too costly and too slow to cope with the changing interconnect systems. Physics-based modeling of the EM becomes necessary to complement the experimental investigation. In the first part of this dissertation, a comprehensive review on the EM models for the interconnections and their evolution over the last three decades is presented. The different EM models are categorized according to their respective simulation methodologies. The primary objective of the review is to re-examine the different EM simulation methodologies and provide a good reference starting point for researchers who are new in the field of EM modeling.
DRNTU::Engineering::Electrical and electronic engineering::Integrated circuits