Electromigration detection by means of low-frequency noise measurements in thin-film interconnections

Low-frequency noise power spectral densities associated with displacements of atoms caused by electromigration were measured on Al-Si (1 percent) resistors at various current densities in the frequency range 5 × 10^{-2 ÷ 2}Hz. The temperature of the resistors was the one set by the current density itself, all the samples having been tested at room temperature. After noise measurement, each resistor was subjected to the current density at which the measurement was performed up to failure. The total electromigration power, measured in the frequency interval 0.1 ÷ 1 Hz was plotted as a function of the failure time for three different series of resistors obtained by means of an RF sputtering process. The measurement system and the characteristic features of the electromigration spectra are described.