Liquid Metal based Stretchable Room Temperature Soldering Sticker Patch for Stretchable Electronics Integration

Researchers are eagerly developing various stretchable conductors to fabricate devices for next‐generation electronics. Most of the major problems in stretchable electronics happen at the connection between rigid and soft parts and the development of reliable soldering material is a major hurdle in stretchable electronics. Though there are attempts to devise new soldering processes for integrating chips and stretchable conductors, they still possess limitations such as mechanical stability, mass production, sophisticated processes, and restricted candidates for conductors and substrates. Here, this study presents a room‐temperature universal stretchable sticker‐like soldering process that can stretchably solder multiple spots at once and directly fabricates a stretchable device in an in situ manner while a target conductor is installed on one's body. The solder developed in this research possesses high conductivity with a unique freestanding feature enabling the process. It can be elongated when directly positioned between a rigid chip and a rigid conductor, demonstrating its extraordinary stretchability. It is expected that this simple but unique stretchable soldering technique utilizing the invented solder will allow the integration of functional stretchable conductors with highly advanced rigid chips for next‐generation stretchable electronics. Major challenges in stretchable electronics occur when connecting rigid chips and soft parts. Thus, a reliable solder and soldering process are necessary. To solve the issue, this study presents a room‐temperature universal stretchable sticker‐like soldering process that solders multiple spots at once and directly fabricates a stretchable device while a target conductor is installed on one's body.