Stress migration study of Cu interconnect with various low-K dielectrics

Three different kinds of low-K materials were selected for stress migration (SM) study. The critical temperature ranging from 150degreesC to 400degreesC was investigated. The difference of failure rate of stress migration among those three low-K materials has been observed. The resistance measurement for monitoring its change was executed at wafer level and package level. The experimental results showed the consistence between wafer level and package level testing. From the results of package level testing, we can screen out low-K material with better lifetime from failure rate. The failure analysis was done after thermal stress. Finally, the comparison of lifetime between low-K materials and FSG was examined.