In Situ SEM Observation and Interface Adhesion Strength Analysis of a Serpentine Interconnect on a Flexible Electronic Composite Film

The buckling deformation of a serpentine interconnect on a flexible electronic composite film is analyzed by a scanning electron microscope miniature tensile stage in situ observation workstation. The buckle formed at the junction of the interconnect pattern under a tensile load is observed. Combined with the buckle size and a theoretical model, the interface adhesion energy and shear stress are derived. The relationship between thickness of the interconnect Cu layer and interface performance is further analyzed. Results show that within the thickness range of 25–500 nm, a 75 nm thick serpentine interconnect has the best adhesion performance on a flexible substrate (about 10.09 J m–2).