Analytical and experimental studies are carried out to evaluate interface strength between submicron structures and substrates on the basis of the fracture mechanics concept. Finite element analyses reveal that the stress intensity near the interface edge between a dot and substrate greatly increases with an increase of the aspect ratio of the dot. Delamination tests for submicron chromium (Cr) dots with different aspect ratios on a silicon dioxide (SiO_2) substrate are conducted by means of a modified AFM. The results show that the smaller load is required to separate the dots with higher aspect ratio from the substrate. This is desirable to evaluate the interface fracture toughness.