Damage evolution during cyclic tension–tension loading of micron-sized Cu lines

Abstract In this study, the low-cycle fatigue properties (1–15,000 cycles) of electrodeposited Cu, which is frequently used as metallization in the semiconductor industry, is analyzed with respect to its microstructure. Freestanding Cu tensile samples 20 μm × 20 μm × 130 μm were fabricated by a lithographic process. The grain size of the samples was modified by using three different process conditions for electrochemical Cu deposition. All samples were subjected to cyclic tension–tension testing performed with a miniaturized stress-controlled stage in situ in a scanning electron microscope until failure occurred. The number of cycles sustained prior to failure depends on the accumulated creep strain and can be related to the failure strain in a tensile test. It will be shown that the microstructure influences the number of cycles to failure and the failure mode.