The time-dependent temperature distribution induced by electric-current heating in a double edge-cracked, unpassivated thin aluminum or gold film interconnect lines is monitored using a high-resolution infrared imaging system. A pure aluminum or gold film of 0.2 micron thickness is deposited by high-vacuum evaporation coating and patterned into test structures of varying widths. The operative mechanisms of mass transport are assessed in view of the monitored temperature profile. The pre-cracked aluminum film showed fine crack growth toward the positive electrode, which originated from the initial crack tips. The crack-tip temperature was close to melting, during propagation. A hot spot was formed afterward between the two elongated cracks and led to failure. The crack growth generated a backward mass flow toward the negative electrode. The gold film showed a different pattern where the original cracks propagated toward each other with a slight tilt toward the negative electrode. The tip temperature was lower than the melting temperature.

This content is only available via PDF.
You do not currently have access to this content.