Scientists are investigating new uses for helium-ion microscopy in nanopatterning. Since it is not limited by the proximity effect of conventional electron-beam lithography, helium-ion technology seems to be an attractive alternative, especially when it comes to printing ever finer features.

For more than two years, the Orion Plus helium-ion microscope from Carl Zeiss has been known for its excellence in imaging uncoated insulating samples and soft materials with subnanometer resolution (resolution specification <0.35 nm). Now – with a growing installed base of Orion instruments – academic and industrial R&D microscopists are extending the diversity of applications to include nanofabrication.

Researchers have patterned 5-nm dots on a 14-nm pitch while other teams have demonstrated well-delineated L-bar lines in hydrogen silsesquioxane (HSQ) resist. This new regime of pattern fidelity is enabled by the large depth of field of the microscope and by the short range of the ion-initiated secondary electrons in typical resist materials. Helium-ion defined patterns in HSQ can easily be obtained without the usual narrow process window constraints often associated with conventional optical and electron-beam lithography.

According to Wei Wu, a senior research scientist in Stan William's Information and Quantum Systems Lab at HP Labs in Palo Alto, Calif., “We look forward to furthering our research regarding the fabrication and imaging of the smallest possible nanoelectronic and nanophotonic features. We see the Orion instrument as a unique, powerful tool that will enable us to continue our record-breaking research.”

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