Wafer-Level Processes for the Manufacturing of Encapsulated Flexible Polymer-Based Implants

This study is motivated by the demand for advanced neuroelectronic flexible polymer-based implants in medical technology. Using a 200 mm wafer-level packaging (WLP) line, the research produces implants with biocompatible polymers, an application-specific integrated circuit (ASIC), high-performing neural electrode materials and barrier layers of Al2O3 and Parylene for moisture protection, all seamlessly incorporated into a single hermetically packaged system, ensuring both functionality and reliability in a compact design. The methodology employs fine gold lines (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$10 \mu ~\mathrm{m}$</tex>) and small vias for high routing density, alongside nanoporous graphene electrodes that provide high-performance bidirectional neural interfacing. A low-temperature bonding process assembles an ASIC onto the flexible substrate, utilizing nanoporous gold pads. Key findings demonstrate the potential for large, flexible sealed devices, with prototypes up to 7 cm, paving the way for advancements in microfabricated brain implant technologies and improved patient outcomes in neurological conditions like Parkinson's disease.