Micromechanical robustness tests of 28nm BEOL layer stacks

The paper describes two micromechanical stress tests, which evaluate the robustness of Back End Of Line (BEOL) layer stacks under mechanical stress, by applying bending stress to FIB prepared pillars and by using nanoindentation in previously prepared cross sections. Conclusions about mechanical robustness of BEOL integration schemes and particular design features are drawn.