Atomistic model of void nucleation and growth during electromigration

Void formation due to electromigration is among the most significant reliability problems in the semiconductor industry. To help gain a better understanding of the atomistic processes involved in void formation under electromigration conditions we have used the Embedded Atom Method (BAM) to determine the structure and formation energies of small voids (up to 20 vacancies) in aluminum and copper both in bulk and at several special grain boundaries. We find that small voids at grain boundaries have a tendency to form diffuse clusters rather than voids with hollow cores. We also show that void energies are described qualitatively by a simple geometric model involving surface and grain boundary energies. We have used the results of our BAM calculations to guide the construction of a kinetic Monte Carlo (KMC) model of void nucleation and growth during electromigration. Our KMC code includes the effects of grain boundaries, grain boundary junctions, stress biased vacancy formation, current biased vacancy diffusion, and vacancy-void interactions. The code can simulate micron scale interconnects for time scales of seconds. We give a complete description of the KMC model and the rates for all events and demonstrate its potential with proof-of-principle calculations.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2012

Author dc:creator

• Richards, David Frank

Contributors dc:contributor

• Adams, James B.

• atomistic model
• void nucleation
• electromigration
• reliability problems
• semiconductors
• Embedded Atom Method
• Kinetic Monte Carlo method

Statement dc:rights

• Copyright 1999 David F. Richards

Language dc:language

en

Identifier

4266042

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/31231