LETI has always played a major role in the development of Mercury Cadmium, Telluride (CMT) detectors, and in the flip-chip technology that goes with the packaging of such infrared arrays. Today with the increasing demand for better spatial resolution we observe the emergence of very large arrays detectors with a very fine pitch. However the hybridization of such fine pitch detectors onto a readout circuit may be very challenging and represents one of the major limiting factors for the development of these detectors. At LETI we have developed a wafer scale flip chip technology to perform large Infrared Focal Plane Arrays (IRFPA) up to 1024x1024 pixels with pitches down to 15 µm. In this paper we describe this hybridization technique which includes bonding, underfilling and polishing steps. The detectors are interconnected to a CMOS readout circuit using very uniform Indium bumps, then all hybridized onto a wafer in one step using a collective method. With our expertise we achieve very high interconnection efficiency, good functionality and a low cost package. We are also presenting reliability results and the optical IR performance of the detectors to further prove the effectiveness of this flip-chip technology. With the emergence of new packaging challenges regarding size, material, and performance this technology may be used for other applications.

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