We employ the vibrating tip of an atomic force microscope as a lithographic tool to mechanically pattern a thin photoresist layer covering a GaAs–AlGaAs heterostructure. High aspect ratio electron beam deposited tips, additionally sharpened in an oxygen plasma, are used to minimize the dimensions of the fabricated quantum electronic devices. The fabrication parameters of the tips and the sharpening process are investigated. With these ultrasharp tips we are able to produce lines and holes with periods down to 9 nm in photoresist. In addition, the very sharp tips yield substantial improvements in the imaging mode. ©1995 American Institute of Physics.