A cost-effective and solderability stretchable circuit boards for wearable devices

Abstract Soft/stretchable electronics accompanied by the nature of matching nonplanar and dynamic surfaces have wide application prospects in the fields of information, energy, medical, and national defense. Current soft/stretchable electronics suffer from high cost, low yield, and poor solderability due to the limitation of fabrication process capabilities of soft electronic materials. We thus present a cost-effective and solderable fabrication process for manufacturing stretchable circuit boards (SCBs). The excellent solderability of the SCBs is demonstrated. The shaped polyimide (PI) layers, which served as solder masks and support layers, allow electronic components with different packages to solder onto the SCBs. The feasibility of the SCBs for application in wearable embedded systems is demonstrated by developing a soft wireless pressure monitoring prototype and a soft posture detection and control system on the SCBs. The tests of stretchability and durability of SCBs and SCB-based embedded systems are carried out. The results reveal that SCBs and SCB-based embedded systems are robust enough for application in wearable systems. The proposed process has been demonstrated as a novel, state-of-the-art manufacturing process for SCB fabrication. It has the potential to extend to other types of soft wearable embedded systems.