Effect of Al-trace dimension on Joule heating and current crowding in flip-chip solder joints under accelerated electromigration

Abstract

Three-dimensional thermoelectrical simulation was conducted to investigate the influence of Al-trace dimension on Joule heating and current crowding in flip-chip solder joints. It is found that the dimension of the Al-trace effects significantly on the Joule heating, and thus directly determines the mean time to failure (MTTF). Simulated at a stressing current of 0.6 A at 70 degrees C, we estimate that the MTTF of the joints with Al traces in 100 mu m width was 6.1 times longer than that of joints with Al traces in 34 mu m width. Lower current crowding effect and reduced hot-spot temperature are responsible for the improved MTTF. (c) 2006 American Institute of Physics.