Local Deformation in Al Interconnects Measured During Thermal Cycling and Electromigration

In‐situ local measurement of thermal and sub‐threshold, electromigration‐induced strains in a 0.3 micron wide Al interconnect was performed using convergent beam electron diffraction (CBED) in a TEM. The CBED method offers the unique ability to probe local strain variations, in this experiment with 0.1 micron resolution. Spatially averaged strain measurements resulting from both thermal treatment and electromigration quantitatively agree with models and data from previous studies. Interesting observations emerged when comparing the local strain distribution within and between grains. Thermal cycling resulted in grain size dependent plastic behavior and electromigration testing led to strain redistribution within individual grains.