As a high-dielectric-constant material, hafnium oxide is one of the promising gate oxides to replace SiO2 for future applications in microelectronics. By atomic force microscopy (AFM), we investigate the AFM-induced anodic oxidation on a hafnium oxide surface and compare the wet etching property of this local oxide with the as-deposited 3 nm HfO2 film in dilute HF solution. Oxide patterns can be reproducibly fabricated and their protruded feature mainly results from the local oxidation of the Si(100) substrate. The AFM-induced oxide pattern has a higher etch rate than the as-deposited HfO2 film due to a greater amount of oxygen.