Modeling of and experiments characterizing electromigration-induced failures in interconnects

As interconnect linewidths continue to scale downward, a detailed knowledge of stress evolution and void growth processes enables a determination of the electromigration-induced failure times of these interconnects. This thesis provides this knowledge through the development of an electromigration simulation MIT/EmSim and through experiments. The stress effect on diffusivity and alloying effects were incorporated into the MIT/EmSim model for Al-based interconnects, demonstrating Cu transport effects consistent with experiments by IBM. The void nucleation and growth process was modeled in long and short lines, and current density exponents for Black's equation determined for several failure conditions. Interconnects can also be immortal, either without void nucleation or by resistance saturation. This complex reliability behavior can be catalogued in the form of failure mechanism maps using simulation or analytical approximations, plotting failure or immortality mode as a function of current density and line length. To extend the MIT/EmSim model to Cu interconnects, experimental observation of void phenomenology and measurement of Cu-based electromigration parameters were performed using Cu/Ta interconnects specifically designed and fabricated at MIT. The knowledge gained from these experiments was used to develop an electromigration model for Cu, and incorporated into MIT/EmSim. Simulations comparing void growth in Al and Cu interconnects indicate that differences in failure times of these interconnects observed in accelerated tests may not necessarily be apparent at service conditions.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Materials Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2001

Author dc:creator

• Andleigh, Vaibhav K. (Vaibhav Kumar), 1973-

Advisor dc:contributor.advisor

• Carl V. Thompson.

• Materials Science and Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/8429

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8429