Packaging concepts for neuroprosthetic implants

A wireless neuroprosthetic implant is under development to provide a device which is able to amplify, transmit, receive and apply data for max. hundred neurons. The brain interface consists of a 100 channel amplifier, data compression, RF communication, power recovery module, two 60-turn planar coils (Au on Polyimide) on a ferrite substrate, SMD components and a 10×10 Electrode Array. The Array is the Utah Array which is a Silicon based structure with tapered Si spikes which have a length of 1.8 mm. For the mentioned components biocompatible wafer level integration and interconnect technologies have been developed based on stacking the coil/ferrite combination of the amplifier IC which is itself flip chip bonded onto the array. The SMD components were reflow-soldered beside the stack as well as special designed ceramic spacer which ensured an electrical interconnection between coil and chip. The whole assembly will finally be coated by a Parylene layer to ensure the bio compatibiliy. Test assemblies and in-vivo experiments showed already the proof of concept. An additional capping technology is under development to ensure very high reliability.