PREDICTION OF ELECTROMIGRATION FAILURE IN W/AL-CU MULTILAYERED METALLIZATIONS BY 1/F NOISE MEASUREMENTS

Low frequency noise measurements were performed on five different wafers of multilevel W/Al-Cu metallization layers fabricated following the same process. The purpose of the study was to establish a correlation between the mean-time-to-failure (MTF) and low-frequency noise-magnitude and spectral shape-observed in these thin films. The spectral shape was found to be in the form 1/f(gamma) where 0.8 < gamma < 1.6 and independent of the interconnect failure time. An inverse relationship was observed between MTF and both the voltage noise magnitude and the total r.m.s. noise in the 1-100 Hz frequency range. 1/f Noise parameters such as the current exponent and the noise magnitude coefficient extracted from the data using the recently proposed model agree closely with those obtained from independent noise measurements on similar samples from the same wafers.