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Title: Focal depth measurement of scanning helium ion microscope

When facing the challenges of critical dimension measurement of complicated nanostructures, such as of the three dimension integrated circuit, characterization of the focal depth of microscopes is important. In this Letter, we developed a method for characterizing the focal depth of a scanning helium ion microscope (HIM) by using an atomic force microscope tip characterizer (ATC). The ATC was tilted in a sample chamber at an angle to the scanning plan. Secondary electron images (SEIs) were obtained at different positions of the ATC. The edge resolution of the SEIs shows the nominal diameters of the helium ion beam at different focal levels. With this method, the nominal shapes of the helium ion beams were obtained with different apertures. Our results show that a small aperture is necessary to get a high spatial resolution and high depth of field images with HIM. This work provides a method for characterizing and improving the performance of HIM.
Authors:
 [1] ; ;  [2] ; ;  [3]
  1. Global Research Center for Environment and Energy based on Nanomaterials Science, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)
  2. Active State Technology Research Group, Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology (AIST), 1-1 Umezono 1-Chome, Tsukuba, Ibaraki 305-8568 (Japan)
  3. Nano Characterization Unit, Advanced Key Technologies Division, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)
Publication Date:
OSTI Identifier:
22311097
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 2; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; APERTURES; ATOMIC FORCE MICROSCOPY; BEAMS; ELECTRONS; HELIUM IONS; IMAGES; INTEGRATED CIRCUITS; MICROSCOPES; NANOSTRUCTURES; PERFORMANCE; SPATIAL RESOLUTION