Electrical Reliability and Bending Test Methodologies of Metal Electrode on Flexible Substrate

Abstract

To develop highly reliable flexible electronics, mechanical reliability during mechanical deformation such as repeated bending is an important issue. Bending test methodologies to estimate long-term reliability during repeated mechanical deformation are attracting substantial interest from related researchers and industry insiders. In this study, four representative bending test methodologies for testing flexible electronics are introduced: free arc bending test, variable radius bending test, sliding plate test, and variable angle test. Correct name and characteristics of each method are also explained. Furthermore, electrical reliability of Cu film on polymer substrate samples was investigated in each bending test method through in situ monitoring of electrical resistance. With different bending test methodologies, different electrical resistance changes were observed. Fatigue damages occurred at different areas. Obtained electrical reliability and failure modes were analyzed by observing crack morphologies.