Feasibility test of a liquid-metal micro-droplet arrays based bonding

Hybrid pixellated detectors are composed from two different elements: the detecting element (sensor) and the detector readout chip. There is an array of interconnections between the sensor and the readout chip, usually made by bump bonding using Indium or solder alloy. In the case of different material than Silicon - like CdTe - used for the sensor element, a mechanical stress will appear in the hybrid entity due to the mismatch of the thermal dilatation coefficients of the used materials. This induced mechanical stress could cause a series of problems, leading to drifts and reduced reliability. We propose to overcome this problem by replacing the solid bonding bump materials by a liquid conductor droplet. These droplets should remain in liquid state in the operation temperature range of the detector and such a way decuple the dilatation of the readout chip and the detecting element.