A 64 x 48 BSI SPAD sensor based on 8"" wafer 3D stacking technology

A 3D stacking process by direct wafer bonding and the resulting sensor are presented to emphasize the potential of this technology for future sensor developments. By using the Fraunhofer IMS own 0.35 mm CMOS and micro systems technology, a 64 x 48 pixel sensor containing back-side-illuminated low-noise single-photon avalanche diodes and in-pixel time-to-digital converters was fabricated. It is being applied om light detection and ranging applications as well as quantum imaging and characterized in both photon timing and counting mode.