Published online by Cambridge University Press: 25 February 2011
A new method is presented to evaluate the resistance to electromigration (EM) of on-chip interconnects. The method is based on high resolution in-situ electrical measurements. In this way, the electrical resistance is measured with high accuracy during electromigration at high temperature. After careful analysis of the isothermal results, it was found that the metallization can be characterized by one parameter: the rate of resistance change (RRC). It is shown that the RRC is very sensistive to the electromigration performance. The performance level of the different metallizations can easily be detected and can be qualified in a quantitative way. The results are also compared with classic Mean Time To Failure (MTTF) results and it is found that there exists an almost linear relationship between the RRC results and the MTTF results. However, the in-situ technique offers the benifit that a metallization can be characterized on a time scale as short as a few days, which is certainly not the case for the classical techniques.