Flexible Integrated Circuits via Stress-minimized Layout and Ultra-thin Chip

Flexible electronics can conform to curved surfaces, playing an essential role in biomedical and industrial electronics. Real-time and wireless data acquisition is crucial for flexible electronics to achieve intelligent functions. Previous works mainly focus on improving the flexibility of front-end sensors, whereas back-end integrated circuits for data acquisition become the bottleneck for developing flexible electronic systems. This work reports flexible integrated circuits (FIC) with stress-minimized layout and ultra-thin chips. 25 μm-thick chips are integrated into the FIC, significantly improving the flexibility of the FIC system. A dispersed layout of chips is proposed to reduce additional stress on the substrate caused by chips during deformation. An optimization model based on mechanical principles is also proposed to minimize the stress endured by ultra-thin chips. The FIC adopts a system-level package method to promote its mechanical reliability essentially. FIC is small, lightweight, and can monitor multiple signals in real-time. The demonstration of FIC opens up new prospects for flexible integrated electronics in biomedical and industrial fields.