ABSTRACT 9500290 Lesser, Michael Techniques have been developed to produce thinned, black illuminated charge-coupled device (CCD) detectors for astronomical observations. These techniques have matured to the point where they are now routinely applied to detectors of many different formats from several different manufacturers. This project extends this development into several new areas of importance to the scientific community, and particularly to astronomy. New techniques will be developed to thin and optimize the very large format CCDs (> 10 cm 2, > 2048x2048 pixels) which are now at the forefront of semiconductor manufacturing technology. These large format devices are necessary for the construction of CCD mosaics to cover the huge focal planes of large telescopes and large telescope spectrographs. The new techniques to be developed include very large area thinning, methods to package large devices for flat and often buttable operation with simplified electrical interconnections, and the capability to characterize the detectors at cryogenic temperatures prior to thinning. Second, the processes will be extended to thin and optimize the very small, high speed readout devices required for the active and adaptive optics instrumentation planned for nearly all large telescopes. These detectors must have the highest possible quantum efficiency in the visible and near-IR to obtain sufficient signal-to-noise in the extremely short exposure times required. The techniques to be developed will be available to the entire scientific community. Back illuminated devices are of great important to many scientific disciplines other than astronomy. Physics, chemistry, engineering, and medicine are all in need of the low light level, wide bandpass imaging detectors which will be developed here. ***