Re-think stress migration phenomenon with stress measurement in 12 years

We measured Internal residual stress change in the copper interconnect in 12 years to confirm the phenomenon that is occurred in acceleration test are equivalent with that is occurred in use condition or not. We have compared the stress change results and void feature and acceleration test results. With these results, we think same phenomenon (void generate on the surface of the interconnect) occur in the room temperature long time storage with high temperature storage. Also, we reviewed the FEM result of residual stress. There are not so large stress at the surface of the line. However void occurs on the surface especially for the Wide Pattern. That suggests diffusion path plays important role in accelerated and use condition.