Improving Electronic Circuit and System Reliability Using Embedded Prognostics

65672 Manufacturing methods for CdZnTe gamma and x-ray pixel detectors, used in medical imaging, are relatively immature. One difficulty with CdZnTe as a detector material is that CdZnTe is more brittle than silicon, so standard bonding approaches frequently result in craters in the detector as well as bond failures. This has forced detector manufacturers to resort to more labor-intensive and costly indium bump bonding techniques. This project will develop mass production techniques for CdZnTe-silicon readout assemblies at low cost. The encapsulated CdZnTe-silicon assembly will be based upon previously developed pre-encapsulated flip chip fabrication technology and low-temperature soldering techniques, with particular emphasis on large quantity manufacturing at low cost. Phase I will develop, qualify, and build test assemblies of CdZnTe into silicon-based array detector electronics, adaptating the flip chip technology with a pixel pitch of 380 microns. Improvements to the solders used to assemble the devices will also be developed, and the devices will be tested at a gamma-ray imaging center. Commercial Applications And Other Benefits as described by awardee: In nuclear medicine, arrays of CdZnTe array detectors can create superior images of injected radiotracers, aiding in removal of tumors. Other applications range from mammography to brain activity monitoring. In nuclear non-proliferation, the imaging of gamma sources has the potential to detect illicit transport of fissile materials.