Using Laser Scanning Microscopy to Determine Electromigration in Molybdenum Disilicide.

With increasing the current density and decreasing the size of chips electromigration becomes more and more important. Electromigration is the movement of atoms in an electrically conductive material caused by current flowing. For aluminum and copper the electromigration parameters and their dependencies have been investigated by a multitude of people and methods. For other materials, this is not the case. Electromigration experiments often use very long times to stress the lines under test in the median to failure experiments. These experiments only give surface-level information about electromigration. More sophisticated methods look at the microscopic or nanoscale effects and influences. Usually, expensive equipment such as scanning electron microscopes (SEM), synchrotrons, or X-ray microtomography are used for these investigations. A workflow enabling the investigation of electromigration on the microscopic scale by using a laser scanning microscope has been developed. With this laser scanning technique, it is possible to achieve results with slightly less accuracy than SEM but with much less effort in preparing the samples. With the electromigrated volume being known, the same procedures as with the electromigrated volumes determined via SEM can be used to calculate electromigration parameters. By varying different experimental variables, a multitude of information about electromigration can be achieved. In this work determining the length for the onset of electromigration is shown.