Increase in mechanical strength by scalloping removal

We investigated the effects of scalloping structure on mechanical strength. We used cantilever specimens having and not having scalloping whose widths, thicknesses, and lengths were 10 μm, 20 μm, and 1.0 mm, respectively. The cantilevers were fabricated by performing the Bosh process with a resist mask. The height and pitch of the scalloping that was formed were 214 nm and 900 nm, respectively. A 50%-KOH (40°C) chemical wet etching was applied to remove the scalloping. The cantilevers were bent in the lateral direction by using a manipulator. The numbers of the cantilevers having and not having scalloping were 7 and 8, respectively. By removing the scalloping, the maximum stress in the cantilever at the fracture increased by 1.2 times. There was no big difference in the fractures between the two types of cantilevers.