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|3D Packaing Technique for a Flexible and Biocompatible Antenna using Z-Axis for Wireless Monitoring of Intraocular Pressure (IOP)|
|Keywords: Nitinol , 3D packaging, Z-axis ACA|
|In this paper, a self-expandable antenna using 3D packaging technique on liquid crystal polymer (LCP) to accomplish miniaturized implantable biomedical sensors for monitoring the intraocular pressure (IOP) within mice eyes is introduced. Limited space of a mouse eye makes the packaging of the sensor system very challenging. Furthermore, in accordance to the incision of the device implantation, minimally invasive surgery is highly demanded. The overall size of the packaged sensor must be less than 12 mils cubed and incision size should be less than 40 mils. In order to achieve the desired dimension, two novel approaches are utilized. First, superelastic alloy Nitinol is used as a flexible antenna to enable the minimally invasive surgery and receive the RF power. Second, the magnetically aligned Z-axis anisotropic conductive adhesive (ACA) and micro-vias through LCP are utilized as a method for the 3D vertical interconnects. The Z-Axis ACA provides a biocompatible alternative for electrical connection between Nitinol and the circuits on LCP because the current soldering method for Nitinol is not biocompatible. To demonstrate the performance of antenna and 3D interconnection using Z-axis ACA and micro-vias, the rectifier connected to LED incorporates with Nitinol antenna on the different layer of LCP. The DC voltage output from the rectifier will be characterized for the ultimate application, powering up back-end IC chip. This 3D packaging technique enables the integration of the whole sensor system in an extremely small form factor and minimizes the incision for surgery to monitor the IOP remotely.|
|Tse-Yu Lin, Research Assistant
West Lafayette, IN