Mechanical BEoL Robustness Evaluation Using Variable Loading Strategies and Acoustic Emission Damage Monitoring

On-chip interconnect stacks (Back End of Line, BEoL) in modern heterogeneous microelectronic products are exposed to various micromechanical loads. Each can lead to different failure modes of the whole system. To locally probe the micromechanical robustness of BEoL stacks, it is necessary to precisely control the mechanical loading conditions there. Three micromechanical BEoL robustness evaluation designs are presented, enabling a load and failure mode-adapted damage induction and identification. Those enable to test BEoL structures below and in the vicinity of Cu-pillars in compression, shear, and tensile mode. Acoustic Emission sensing capabilities are implemented to detect the very early stages of mechanical failures.