The Application of a Dynamic Technique to the Study of Electromigration Kinetics

A temperature-ramp technique is presented that enables determination of the kinetic parameters for electromigration processes. With this method, pre-exponentials and activation energies can be measured in a single experiment requiring a few hours. The technique is applicable to both practical and fundamental studies of electromigration. For example, in terms of the former, reliability factors for conductor lifetimes can be readily determined. As far as the latter, new conductor compositions can be rapidly screened to ascertain their electromigration behavior. Temperature-ramp Resistance Analysis to Characterize Electromigration (TRACE) has been applied to thin-film aluminum conductors. Results have yielded activation energies in agreement with literature values. Furthermore, the TRACE results have been used, along with resistivity results from the literature, to determine the current density effect on the pre-exponential factor. The value of the current density exponent thus determined is in accord with the range reported in the literature for Mean Time to Failure (MTF) experiments. The TRACE technique has also been used to determine the effect of hydrogen ambients on electromigration damage (EMD) kinetics for both aluminum and Al-2%Cu thin-film conductors. The effects of hydrogen ambients on EMD kinetics have been determined to be more complex than suggested by prior results in the literature.