Flexible Ultra-Thin Chip-Film Patch for Integration of Electronic Components for Biomedical Applications

Abstract:
Hybrid Systems-in-Foil (HySiF) comprise large-area thin-film electronics and ultra-thin, high performance CMOS chips integrated into a flexible polyimide film. Chip-film patch (CFP) technology is employed to realize HySiF integration. This study not only demonstrates the successful fabrication of a CFP that is part of the FLEXMAX project, but also investigates the electrical operation of the CFP ensemble and the mechanical stability under physiological aspects. The latter could be decisively improved by using an encapsulation strategy, namely a plasma enhanced atomic layer deposition (PEALD) process. Aluminum oxide and titanium oxide with two different layer systems ranging from 3 nm/7 nm to 5 nm/15 nm are sequentially deposited on a CFP to create a hermetic barrier that protects the CFP from water vapor and ion infiltration. The in vitro tests show extensive stability of the electrical signal response over several months compared to uncoated CFP samples. The results provide a solid platform for the fabrication of an ultra-thin flexible CFP system, which can equally be applied as an implantable variant in biomedicine.