Advisory Committee Chair
David L Littlefield
Advisory Committee Members
Arief Suriadi Budiman
A Abdollah Mirbozorgi
William D Nix
Dean Leo Sicking
Document Type
Dissertation
Date of Award
2022
Degree Name by School
Doctor of Philosophy (PhD) School of Engineering
Abstract
Reliability of today’s interconnect lines in microelectronic devices is critical to product lifetime. The metal interconnects are carriers of large current densities and mechanical stresses, which can cause void formation or metal extrusion into the passivation leading to failure. The modeling and simulation of stress evolution caused by electromigration in interconnect lines and vias can provide a means for predicting the time to failure of the device. Reliability and performance are equally important in the microelectronics industry of today. Product lifetimes are expected to be as high as 10 to 15 years of service. A typical microprocessor has millions of interconnect lines and the probability of line failure under operating conditions can be quite high. The interconnects in a modern microprocessor unit must be carefully engineered and tested to ensure that they are highly reliable. Electromigration has been modeled as momentum transfer between conducting electrons and lattice atoms in a current carrying metal line. Early microelectronic devices were manufactured with large line cross-sectional areas and therefore electromigration was not an issue due to the low current densities. As devices and interconnects scaled down in feature size, the current densities became extremely large and electromigration became a key reliability concern. The current densities in modern microelectronic devices can be as high as 10 mA per square micron. We investigate and present less researched electromechanical mechanisms that produce migration of lattice ions towards the anode of a current carrying conductor without the a priori assumption of only an electron wind force and stress gradient as driving the migration. i The work presented in this dissertation focuses on new models, their significance, new tools and newly suggested experiments to validate the derived models. We attempt to look at contemporary models of atomic flux during electromigration by incorporating forces on migrating ions that always existed but were left out in the models.
Recommended Citation
Morusupalli, Raghavendra Rao, "Electromechanical Mechanisms of Electromigration - Novel Approaches" (2022). All ETDs from UAB. 353.
https://digitalcommons.library.uab.edu/etd-collection/353