This is an in-situ movie of electromigration in Al 0.1% Sc obtained
J. Doan, S. Lee, J. Bravman, P. Flinn of Stanford and T. Marieb of Intel.

Please go to their website for even more movies and information.

The line is 300 microns by 30 microns by 0.6 microns. The test
runs for 250 minutes. The sample has been coated with 0.4 microns of
PECVD Nitride. The test is at 250C and the current density is 20 mA/(square micron).

The color is a measure of the thickness of the conducting material---blue is
thick material and red is no conductor at all. The movie shows 6 segments as
rows, these form a continuous straight conducting path in the actual experiment.

You will see voids form and move due to electromigration: