Interfacial competing fracture in peeling of bi-interface film-substrate system

Abstract

In transfer printing technology, the stamp, device, and substrate together form a typical bi-interface film-substrate system. Understanding the interfacial peeling and competing fracture behaviors of this structure is crucial for optimization of the transfer printing process. Current researches often focus on how the interfacial characteristics, such as interfacial strength, toughness, and defect, influence the interfacial fracture path, however, non-interfacial factors within the system are frequently overlooked. This oversight may result in challenges such as low yield rates and overreliance on empirical knowledge in practical transfer printing. In present study, we develop a theoretical peeling model for the bi-interface film-substrate system, taking into account the arbitrary peeling angle and the finite scale of the device. Based on the model, we systematically analyze the system’s interfacial competing fracture behavior during peeling and the factors that influence it. An analytical solution is derived for the cohesive zone length, which is shown as a function of the peeling angle, film bending stiffness, and interfacial properties. The interfacial competing fracture map is also obtained to identify the fracture path. The present study highlights the effects of non-interfacial factors, such as film bending stiffness, peeling angle, and device scale, on the interfacial competing fracture. It is found that increasing the film's bending stiffness, decreasing the peeling angle, and reducing the device scale would promote fracture at the device/substrate interface, while the opposite conditions favor fracture at the film/device interface. These theoretical findings are further validated through finite element simulations and experimental methods. The results of this study are beneficial for optimizing the transfer printing processes to improve yield rates and may also inspire the development of new transfer printing technologies.