Development of a bump bonding interconnect technology for GaAs pixel detectors

Pixel detectors made of semi-insulating GaAs have already been successfully tested for their application as tracking detectors in high energy physics experiments. For the operation of large arrays of pixel sensors, a technology allowing a two dimensional interconnect with a high yield is necessary. For this purpose an indium based bump bonding process has been developed. Especially the generation of the indium bumps on the surface of the GaAs pixel detector was optimized. The development of these processing steps is described. In order to investigate the influence of these steps and of the bonding procedure on the detector performance, I–V-characteristics of bump bonded GaAs pixel detectors were analyzed.