"Microflex" - A new assembling technique for interconnects

A new interconnection technique has been developed that allows versatile mu ltiple strand connections between microsensors, sensor arrays, and chips de signed for wire bonding. The new technique has been termed "Microflex inter connection" technique (MFI). Conventional wire bonding technique is commonly restricted to planar interc onnects with a limited degree of freedom for placing microsystem components in hybrid assemblies. The MFI technique has overcome this limitation by in terconnecting microsystem components through custom designed flexible subst rates with embedded metallized conductors, pad arrays for integrated circui ts' assembly and substrate integrated electrodes. Standard CMOS components without additional pad metallization can be used. The integration density o f the MFI technique corresponds to one of the flip-chip technology. Special advantages of the MFI technique are three-dimensional interconnects, the f lexibility in design and shape, and easy visual inspection of alignment qua lities. The method is especially suitable for small volumes of customer spe cified devices and biomedical implants because all materials used are bioco mpatible. Within this paper, the MFI technique is introduced, described in detail, an d tested according to international standards. The evaluation of the electr ical and mechanical properties of the interconnection sites exhibited promi sing results regarding stability and reliability. First applications in the biomedical field were presented on the example of a neural implant and a s ensorized cardiac catheter.