Low-temperature bump bonding of Timepix readout chips and CdTe sensors at Different Sensor pitches

The article describes a low temperature bump bonding process to flip chip bond CdTe sensors on Timepix readout chips with two separate pixel pitches: 55 μm and 110 μm. Because the sensor properties of CdTe start to degrade around 150 °C, InSn (48-52) solder joints were used. The solder bumping process flow and flip chip bonding routine are described, and leakage currents and radiation images are compared at different pitches. The results show low leakage currents and a good bump bonding yield with both pitches.