[NanoIC topic] Mechanics and characterisation of voiding in wafer-wafer bonding using synthetic Schlieren

Particle-induced bond defects manifest as relatively large voids trapped between wafers and split the oncoming bond front. Such voids not only create locally unbonded gaps in the vicinity of the particle, but also create a tail of voids downstream, in the direction of the front’s propagation, as the split- bond- fronts collide with each other in closing the unbonded region. We aim to visualize this parasitic effect of void-tail formation using high-speed imaging, and fully characterize their formation in terms of the mechanical parameters of the system.