Characterization of silicon/glass anodic bond initiation toughness

We describe an approach to characterize the initiation toughness (resistance of anodic bonded interfaces to crack initiation) of silicon/glass anodic bonds. The approach is based on the existence of a universal stress state at the most common site of fracture initiation, the silicon/glass interface corner. In order to validate the approach we designed and fabricated relatively simple anodic bond test specimens and carried out mechanical test program to characterize the initiation toughness. We find that while failure stresses vary significantly with bond area, the initiation toughness is independent of bond area