Cohesion Failure Analysis in a Bi-layered Copper/Kapton Structure for Flexible Hybrid Electronic Sensing Applications

Cohesion failure analysis of a bi-layered flexible copper tape/Kapton polyimide structure (BL-FC/KP-S) for preventing failures in flexible hybrid electronic (FHE) sensing systems was investigated by analyzing adhesion and stress distribution. The T-peel and stretch deformation tests were used for studying the adhesion strength and the stress distribution in the overlayer copper, respectively, to understand the stability of the attached copper on Kapton polyimide substrate. Commercially available copper tape and Kapton polyimide were employed to form the BL-FC/KP-S. An adhesion strength of 1.29 kg/in was measured between the flexible copper tape and the Kapton substrate using a T-peel test method. A comparative stretch deformation technique on bare Kapton and the BL-FC/KP-S was implemented and a cohesion strength of 4 gr/mm was measured at the copper/Kapton interface, for an applied strain of 9% and 21% during the delamination process.