3-D electronics interconnect for high-performance imaging detectors

We describe work that extends three-dimensional (3-D) patterned overlay high-density interconnect (HDI) to high-performance imaging applications. The work was motivated by the rigorous requirements of the multiple-pulse imager for dynamic proton radiography. The optical imager has to provide large (>90%) optical fill factor, high quantum efficiency, 200-ns inter-frame time interval, and storage for >32 frames. In order to accommodate the massively parallel electronics including the signal storage for a large number of frames, it is necessary to provide novel 3-D interconnect and packaging architectures. Recently, a 3-D interconnect technology was successfully demonstrated to assemble a stack of 50 signal-processing chips into a cube. Each chip contained test connections (interconnect continuity only) simulating 166 channels of pixel read-out electronics. Test cube assemblies, based on these mock-up integrated circuits, have been fabricated to explore the feasibility of constructing functional cube arrays. A novel 3-D integrated sensor-electronics (mirror-cube) imager architecture is proposed. We also briefly review progress in the custom fast image-processing electronics.