| Abstract: |
We report tests to failure of 300 nm wide damascene copper interconnect lines in silicon oxide dielectric, under high amplitude, low frequency alternating current. The cyclic minimum and maximum resistances were obtained from the measured voltage and current waveforms, and remained essentially constant over the lifetime tests. In the lines tested to failure under voltage control at the highest current levels, observed features of the remaining copper deposits seemed to indicate repeated melting over multiple cycles of current. The lifetimes, plotted against temperature, formed a nearly straight line on a semi-log plot, even though the failures, particularly those run under voltage control, became considerably less catastrophic for the longer lifetimes. Understanding the individual and combined effects of the temperature, current, and thermomechanical stresses will open up the possibilities for utilizing these electrical tests in systematic assessments of interconnect reliability and quality control. |
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