Flip Chip Bonding

Advacam team has been involved in in the flip chip assembly of hybrid pixel detectors with various pitches and sizes since 2002 and a special competence has been developed over the years. Today a commercial flip chip service is provided in small-scale production for customers’ high-value components. In addition to production-oriented work, small R&D projects are continuously done for the customers.

Standard flip chip bonding

Most of the flip chip commissions are about bonding CMOS ASICs on silicon sensor modules, but compound semiconductor sensors (GaAs, CdTe & CdZnTe) are becoming more and more popular. Advacam has developed its own wafer bumping and flip chip processes for these sensors, and nowadays they can be routinely flip chip bonded with high success rate. Typical solder structure is such that the solder bumps are deposited on the ASIC readout wafer with the UBM and the sensor wafer has a solderable UBM pads.

SEM image of a cross section of a flip chip bonded Si sensor to the CMOS readout ASIC.

Special flip chip bonding

In special components e.g. CMOS chips with Cu Through Silicon Vias (TSV), it is beneficial to deposit the solder bumps on the sensor wafers instead of the very expensive CMOS wafer with TSV’s.

Edgeless sensor flip chip bonded to thin MPX3 TSV ASIC chip