Effects of self-heating on integrated circuit metallization lifetimes

The authors present simulation results, an experimental technique, and a model for estimating the temperature rise and time-to-failure (TTF) of interconnect. They introduce the concept of derating factor for electromigration TTF due to self-heating. The derating factor is the factor by which the lifetime is reduced by temperature rise in the interconnect. It is shown that in the limit of high frequencies, the temperature rise can be estimated in a straightforward manner using the root-mean-square current density after the thermal resistance of the structure has been determined from DC measurements. The implication of the temperature dependence on J/sub rms/ for the usually quoted J/sub ave/ design rule was examined. It was determined that self-heating is probably not significant for the usual design rule average current density of 1*10/sup 5/ A/cm/sup 2/ for operation at frequencies >10 MHz and duty factors >0.1%. However, if the design rule is increased to 1*10/sup 6/ A/cm/sup 2/, self-heating might become significant.<>