Microstructure of thermal hillocks on blanket Al thin films

The microstructure of thermal hillocks on blanket Al thin films has been studied for the first time by several techniques, including sectioning and imaging in a focused ion beam system. It is found that the new material in the hillock area lifts the original film up and in some cases penetrates it. The micrographs also reveal the grain structures and give valuable insight into the mechanisms of hillock growth.