Electromigration critical length effect in Cu/oxide dual-damascene interconnects.

Electromigration tests at temperatures between 340 and 400 °C and current densities between 1.0 and 3.0 MA/cm[sup 2] have been performed to determine the temperature dependence of the critical length effect in 0.5-μm-wide Cu/oxide dual-damascene interconnects with 0.1 μm silicon nitride (SiN[sub x]) passivation. A focused-ion-beam-induced contrast imaging technique is used to locate failure sites of critical length test structures. Statistical analysis [E. T. Ogawa et al., Appl. Phys. Lett. 78, 18 (2001)] yields a threshold-length product (jL)[sub c], of 3700 A/cm, and a temperature dependence is not observed within the temperature range 340–400 °C. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]