A new approach for the fabrication of flexible copper microstructures via scratch-induced selective electrodeposition

Abstract Owing to their excellent mechanical compliance, flexible electronic components play a crucial role in diverse applications. Controllable fabrication of metal microstructures on flexible substrates remains challenging, particularly in achieving both low electrical resistance and site-controlled preparation. In this study, a novel method is proposed for fabricating high-quality flexible Cu microstructures via scratch-induced selective electrodeposition and structure transfer. The patterned Cu structures, electroplated on silicon scratches, were transferred onto flexible substrates using photoresist mask as sacrificial layer. It was found that crystal damage (amorphization and lattice distortion) generated during scratching significantly influences the electroplating quality on scratched areas. Reducing the thickness of the damaged layer leads to fine-grained and homogeneous deposition. Moreover, compared with SiO 2 mask, the scratch on photoresist mask-coated silicon surface promotes the formation of high-quality Cu structures. Furthermore, the effect of electroplating additives was investigated to obtain optimized surface morphology and structural integrity. It is also noted that, by using the photoresist as sacrificial layer, the fabricated Cu structures on silicon can be transferred onto polydimethylsiloxane substrates, presenting low electrical resistance and high flexibility. Through the above approach, we have successfully fabricated flexible Cu coils with sensitive magnetic response and transparent heating electrodes with rapid heating performance.