Microbumping technology for hybrid IR detectors, 10μm pitch and beyond

In order to assess the feasibility of a more mass-manufacturable process, IMEC has developed microbump technologies down to 10μm pitch. The micro bumps are based on Cu/Ni/Sn semi additive plating and built at wafer level using a process fully compatible with standard packaging infrastructures. Different test materials with 15, 10 and even 5μm pitch Sn microbumps were processed for a total amount of 640 × 512 (VGA), 1024 × 768 (XGA) and 3072 × 3072 pixels respectively. The microbumped Si chips were assembled with glass chips, InGaAs and HgCdTe compounds and subjected to thermocycling reliability evaluation.