Wide line, low current electromigration in Al-Cu metallization with refractory underlayer

A one-year electromigration experiment was performed on an 8.9 /spl mu/m wide serpentine metal structure, at stress current densities from 0.3 to 1.3 MA/cm/sup 2/. Resistance decreases were observed and explained, and used to estimate a drift velocity which is linearly proportional to the difference between the stress current and the current threshold. The activation energy was found to be approximately 1.1 eV.<>