Liquid Droplet Stamp Transfer Printing

Abstract 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.