The objective of this 2 year project is to study, develop, and demonstrate a non-hermetic, biocompatible micro- package technology for microfabricated wireless implantable devices or systems used in bio-medical research and clinical care. The volume and weight of these micropackages shall be as small as possible, with a total thickness of the conformal package layers being less than 0.25 mm and the added volume only ~20-80% of the original system before packaging (compared to ~10x or more volume increase in conventional hermetic packages). The implant life time will be from a few months to a few years. Advances in integrated circuits, micro- and nano-electromechanical systems (MEMS/NEMS), as well as thin film rechargeable batteries and other miniaturized devices, make it now possible to realize the great potential of microfabricated implantable or surface-attached biomedical instruments for life science research and health care beyond what microelectronics alone could offer. The volume and weight of these microsystems are reduced and the performance is enhanced over several orders of magnitude as compared with their macroscale counterparts of two decades ago. However, a critical challenge, and thus a bottle neck to clinical implementation, is the lack of a suitable micropackage that is on the same size scale as these micro-systems. The conventional hermetic box package used to protect microelectronics is too restrictive to meet the needs of next-generation implantable microsystems. This project aims to explore and validate the following hypotheses: (i) A non-hermetic thin film micropackage technology for microfabricated implantable devices can be developed. (ii) A package made from multilayered thin film coatings will have a significantly reduced density of coating faults and a greater life time as compared with a single layer of the same thickness. (iii) A multilayer consisting of nano-meter thin brittle ceramic films interlaced with ductile films can be an excellent, flexible vapor barrier with mechanical flexibility. (iv) Micropackaging techniques for functional implantable micro-system can be developed using standard MEMS fabrication tools combined with additional MEMS-friendly processes such as laser cutting, ultrathin film deposition (i.e., atomic layer deposition), surface cleaning methods, and clean chemical processing chambers. This two-year research effort will primarily focus on the following tasks: (i) Developing the micropackage concepts and techniques to verify the aforementioned hypotheses using micropackaged PCBs. (ii) Designing and packaging RF recharge and controlled pilot telemetry devices for evaluation in the accelerated lifetime test set-up (e.g., immersion in 85 C saline solution). (iii) Implant functional telemetry units in animal models to demonstrate the merits of the micropackage technology in functional implantable micro-systems for biomedical research and health care, where the device size, weight, package cost and turn-around time are important.
Project Narrative This proposal aims to develop a novel, non-hermetic, low-profile packaging technology designed for long-term protection of environmentally-sensitive components in wireless, implantable microdevices, thus addressing the most significant technical bottleneck inhibiting the clinical implementation of these technologies in applications such as neural interfacing, cardiac care, and urinary control to name a few.