Tip-enhanced probe design for nanometrology

Scanning near-field optical microscopy (SNOM) employs many different forms of optical probes to achieve sub-diffraction limited imaging. The first commonly used probes utilized optical fibers pulled or etched to a small end diameter. This technique has successfully demonstrated spatial optical resolution better than 100 nm. These original near-field probes utilized a coating of aluminum on the sidewalls to achieve field confinement. The fabrication process had problems with irreproducible coatings (leading to blockage or leakage of light), insensitive scanning surface interaction mechanisms, or taper issues leading to low throughput. To overcome these issues, a probe design which involved illumination of sharp metals with optimal polarization was developed to achieve higher topographic and optical spatial resolution. This technique has been termed tip enhanced near-field scanning optical microscopy (TENOM). Although this technique overcomes many of the issues with using fibers, it introduces other issues. This work will cover how one overcome some of the issues with metal probes as well as presenting show our latest results.