Speaker
Description
The Selena experiment aims to search for neutrinoless double beta decay in ⁸²Se using hybrid amorphous selenium (aSe)/CMOS pixel sensors, in which a thick aSe layer is deposited directly over a fine-pitch CMOS readout chip. A high-voltage is applied across the aSe to drift and collect ionization. Current R&D devices are Topmetal-Se bare die, featuring 100×100 pixel array with exposed metal contacts, glued on a PCB. The connection between the die and the PCB has been an ongoing challenge, since any irregularity on the aSe surface distorts the electric field and introduces unwanted leakage-current paths. We present a possible solution by micro-extrusion printing of conductive silver traces between chip and PCB pads, resulting in a low-profile interconnect and a near-planar surface for uniform aSe deposition.