A Quantitative Study of Void Nucleation Times in Passivated Aluminum Interconnects

Abstract

AbstractAccelerated electromigration tests were performed in a High Voltage SEM (HVSEM). These experiments were conducted on 10 identical, passivated Al interconnect test structures at a temperature of 237°C and a current density of 30mA/µm2. Simultaneous testing and observation of the entire structure allowed the void nucleation times to be measured. Two normal distributions fit the nucleation times. The second of these distributions coincides roughly with the distribution of failure times of the test structures. Fracture of the passivation is hypothesized as the mechanism that causes the concurrent late nucleation and failure processes.