Thin, narrow, lines were reactive ion etched from a highly textured aluminum film deposited on (100) silicon substrates; some arrays of lines were covered with a passivation layer of silicon nitride. Passivated and unpassivated lines were heat treated at 400°C.
Voids were present in nitride covered lines which were aged for over three months at room temperature as well as in nitride covered lines examined immediately after heat treatment. Voids were not visible in bare, heat treated lines. Void nucleation occurred at the points of intersection of grain boundaries with line edges and growth appeared to follow grain boundaries.