A METHOD FOR PREPARING ATOM-PROBE SPECIMENS FOR NANOSCALE COMPOSITIONAL ANALYSIS OF METALLIC THIN-FILMS

A method for preparing atom probe field ion microscope (APFIM) specime ns for nano-scale characterization of metallic thin films was develope d. Magnetic thin films of Fe-Ta-C and Co-Cr were sputtered on a Cu coa ted glass substrate. Resist patterns with nearly the same width as the thickness of the film were printed on the film by a photolithography process. The resist coated film was, then, ion milled until the Cu buf fer layer appeared. After removing the remaining resist film by aceton e, the Cu underlayer was dissolved by a chromic acid solution. The fin e rods were picked up on top of tungsten wires with a precision goniom eter stage while observing by an optical microscope. These rods were t hen sharpened to FIM tips with a radius of approximately 10 nm by the pulsed micropolishing technique.