High-density hybrid interconnect technologies

The ultra-high density hybrid flip chip integration of an array of detectors and its dedicated readout electronics can be achieved with a variety of solder bump techniques such as pure Indium of Tin alloys, (In, Ni/PbSn), but also conducting polymers, etc. Particularly for cooled applications or ultra-high density applications, Indium solder bump technology (electroplated or evaporated) is the method of choice. The state-of-the-art of solder bump technologies that are to a high degree independent of the underlying detector material will be presented and examples of interconnect densities between 5e4/cm2 and 1e6/cm2 will be demonstrated. For several classes of detectors, flip-chip integration is not allowed since the detectors have to be illuminated from the top. This applies to image sensors for EUV applications such as GaN/AlGaN based detectors and to MEMS-based detectors. In such cases, the only viable interconnection method has to be through the (thinned) detector wafer followed by a based-based integration. The approaches for dense and ultra-dense through-the-wafer interconnect "vias" will be presented.