Collective hybridization of tantalum absorbers on a silicon thermistors array for X-ray spectro imaging devices

Abstract

We are developing a low temperature X-ray spectro-imaging camera for astronomy concerns. A key technology for the success of this development is the flip chip collective hybridization of tantalum absorbers elements on a silicon thermistors array with pure indium solder as the thermal and mechanical link. This paper first describes the structure of the detector. Then, the 4 mains challenging steps of the collective hybridization of tantalum elements are detailed. In particular is discussed the properties of a new Ti/Au UBM suitable for In hybridization. Finally, first mechanical mock-ups are presented, showing collective hybridization of 8*8 tantalum pixels array with a 500 mum pitch on 5 mum thin brittle silicon membranes.