Method for evaluating sharpness of tip apex of a cantilever for the atomic force microscope

A chemically textured alumite disk with micropillar posts on its surface is found to be a good standard sample to evaluate sharpness of atomic force microscope tips in the range of a few to a few tens of nm. The tips evaluated were silicon nitride cantilever with a normal pyramidal tip, one with a carbon microtip deposited by the electron beam method and one with a microtip formed by the focused ion beam method (FIB tip). The FIB tip has a fairly sharp tip apex so it can show very fine ridges around micropillars precisely.