Liquid Droplet Stamp Transfer Printing

Despite the increasingly significant role of flexible electronics in information, energy, and medical treatment, their integration with a special-shaped interface remains an unresolved challenge. The traditional transfer method, as a core technology of device integration, is still unsuitable for thinned chips and 3D sensors. Solid-contact elastomer stamp sometimes causes cracks while non-contact method such as sacrificial layer method fails to achieve precise positioning transfer. Herein, the authors present liquid droplet stamp transfer printing (LSTP) with a high yield ratio which allows flexible devices to be transferred form silicon wafer to complex special-shaped interfaces. Following the transfer scheme, the regulation of interface force is demonstrated with different thin-film patterns. Besides, the liquid droplet stamp is designed as an efficient tool to transfer thinned inorganic flexible chips. A thinned micro light emitting diode, extensively used in large-scale manufacturing of flexible circuits, is transferred and lighted successfully. In addition, a new method to fabricate 3D sensors is proposed with the liquid droplet stamp, which provides a new way of manufacturing wearable antenna and reconfigurable devices. Consequently, the LSTP has great potential for future sophisticated and system-level flexible devices transfer printing and plays a vital role in the research of 3D flexible electronics.