4096 x 4096 pixel CCD mosaic imager for astronomical applications

A large-format CCD imager to be used in a 2 X 2 mosaic array has been designed and fabricated. Each quadrant is an independent imager of 2048 X 2048 15 micrometers pixels, designed to be edge-butted on two sides. After sawing and mounting the individual dice in custom, buttable packages, the authors assembled a 4096 X 4096 mosaic array measuring more than 61 mm on a side with just 400 microns dead space between imaging areas. With this buttable package design, each quadrant of the mosaic can be separately tested, optimized, and, if necessary, replaced. Also described are smaller 2688 X 512 15 micrometers pixel CCD imagers designed for spectrographic applications that were fabricated using space in the chords of the same 100 mm silicon wafer containing the 2048 X 2048 edge-buttable devices.