Grahame Rosolen, nanofabrication expert at CSIRO, Sydney, Australia, will present the following seminar from the Pacific Rim Conference in Nanoscience (7-11 September 2004). The seminar will be available for viewing and discussion through the Nanotech Hub at http://nanotech.colayer.net/
Nanolithography with a Modified Scanning Electron Microscope
Electron Beam lithography offers the ability to expose patterns with nanoscale dimensions. It may be used to directly fabricate individual nanostructures or to make nanoscale masters for mass production of nanoscale devices. A direct-write electron beam lithography instrument has been developed based around the electron optics, sample stage and vacuum system of a scanning electron microscope (SEM). The instrument has been used to write a variety of devices with nanoscale dimensions including nanowires, optical detectors, surface acoustic wave devices, high electron mobility transistors, diffraction gratings and optically variable devices. A computer controlled pattern generator and pattern alignment system has been developed and interfaced to the deflection coils, electron detector and beam blanking of the SEM. This provides digital control of the electron beam for exposing patterns and also allows images to be acquired for use in pattern alignment prior to exposure. A novel image correlation technique is used to align the exposed patterns with structures already on the sample. The ability to prepare the pattern data, exposure the nanoscale patterns and subsequently image the fabricated devices, all with the one instrument, enables rapid prototyping and study of a wide range of nanoscale devices.