In the previous study, crack initiation from a free edge along an interface between Cr microdot and SiO₂/Si substrate was experimentally investigated and theoretically analyzed within the framework of fracture mechanics. Since the size of stress concentrated zone confined to a nanoscale, it was questionable whether the fracture mechanics was still valid or not. The cohesive zone model (CZM) has advantages in describing cracking behavior along an interface. However, its 3-D applicability in nanoscale components has not yet been investigated. In this study, a three-dimensional cohesive zone model of exponential type is used to extract the toughness for the crack initiation along the interface between Cr microdot and SiO₂/Si substrate with the nanoscale stress concentration. After the CZM parameters for the Cr/SiO₂ interface cracking are calibrated by an experiment, its validity is examined by other experiments. This study demonstrates the applicability of the three-dimensional CZM to the characterization of interface fracture behavior in nanoscale components.