Microflex: a new technique for hybrid integration for microsystems

This paper describes a new interconnection wire method which allows versatile multiple strand connections between microsensors: sensor arrays and integrated circuits (IC). The interconnection method is termed Micro Flex Interconnects (MFI). One example for this technology is the connection of implantable, highly flexible neural micro devices to electronics for interfacing to the external world. The interconnection technique is based on a novel multilayer process using polyimide (Du Pont PI 2611). The thickness of the polyimide structure ranges from 5 to 15 μm including the insulation layers. Several metallization layers can be embedded in the material. This approach exhibits same advantages. The involved material is non-toxic and the ICs do not need any additional bond pad metallization. The MFI technique has been proven long-term stable. The metallization material can be chosen accordingly for electrodes, conducting lines, and connection pads. An commercial ball wedge bonder is the only equipment needed to perform the MFI method