LOW-TEMPERATURE THERMAL-OXIDATION SHARPENING OF MICROCAST TIPS

The authors report the fabrication of sharp tips by casting a tip material into a sharpened silicon mold whose original shape was modified by the growth of a nonuniform, low temperature, thermal oxide. The addition of the oxide layer is the only significant difference between this process and processes currently being used by the majority of commercial producers of atomic force microscope force sensing cantilevers. While commercially available molded tips typically have radii of curvature of approximately 500 angstrom and aspect ratios of 0.5 or less, tips made in the modified molds have radii of curvature as low as 110 angstrom and aspect ratios of 0.95. This technique is useful when sharpness, uniformity, and low cost are required.