Application of carbon nanotube probes in a critical dimension atomic force microscope

The ever decreasing size of semiconductor features demands the advancement of critical dimension atomic force microscope (CD-AFM) technology, for which the fabrication and use of more ideal probes like carbon nanotubes (CNT) is of considerable interest. The recent progress in the precise control of CNT orientation, length, and end modification, using manipulation and focused ion beam processes, allowed us to implement ball-capped CNT tips and bent CNT tips for CD-AFM. Such CNT tips have been tested for the first time in a commercial CD-AFM to image a grating and line edge roughness samples. We found out that CNT tips can reasonably scan the pattern profiles including re-entrant sidewalls with the CNT tip geometries we used and with the available range of scan parameters. There still remain important issues to address - including tighter control of tip geometry and optimization of scan parameters and algorithms for using CNT tips.