Conformal Peeling of Device-on-Substrate System in Flexible Electronic Assembly

Continuous peeling of thin chips and flexible devices from a donor to an acceptor is critical for high-efficiency roll-to-roll (R2R) manufacturing of flexible electronics. Here, we propose an R2R conformal peeling technique for the flexible device-on-substrate electronic assembly. First, a mechanical model is established for flexible multilayer structures conformed on curved surface, such as peeling blade, and the corresponding analytical solution of the interfacial shear stress and peeling stress of the adhesive layer is given. Then, the influence of material property and geometrical size of the device (Young's modulus of different layers and thickness of various layers), the geometric shape of peeling blade (peeling radius and conformal angle), and R2R process parameters (tension and speed of substrate) are analyzed by the theoretical model and experimental test. The peelability law of delaminating devices from the substrate is established for the conformal peeling process. Finally, the design method for a peeling blade is proposed, and the core is to determine the diameter of the peeling blade. It is proofed by the peeling experiment of multilayer electronic devices in the packaging of radio-frequency identification tags.