Recent Progress in Understanding the Imaging and
Metrology using the Helium Ion Microscope
Michael T. Postek. Andras E. Vladar and Bin Ming
1
National Institute of Standards and Technology,
100 Bureau Drive Gaithersburg, MD 20899
ABSTRACT
Nanotechnology is pushing imaging and measurement instrument technology to high levels of required performance. As
this continues, new barriers confronting innovation in this field are encountered. Particle beam instrument resolution
remains one of these barriers. A new tool for imaging and metrology for nanotechnology is the scanning Helium Ion
Microscope (HIM). The HIM is a new approach to imaging and metrology for nanotechnology which may be able to
push this barrier lower. As a new methodology, it is just beginning to show promise and the number of potentially
advantageous applications for nanotechnology and nanometrology has yet to be fully exploited. This presentation will
discuss some of the progress made at NIST in collaboration with the manufacturing community in understanding the
imaging and metrology for this new technology.
Keywords: Helium ion, microscopy, HIM, scanning electron microscope, SEM, nanomanufacturing, nanometrology
1. INTRODUCTION
The scanning helium ion microscope (HIM) is a new tool for nanotechnology. As reported in earlier papers [1,2,3,4], the
HIM is a new approach to imaging and metrology for nanotechnology which may be able to push the current resolution
barrier lower. This instrument also promises the potential for new imaging modes, as well as, charge free imaging
without the need for conductive coating. But, successful imaging and metrology with this instrument entails new ion
beam/specimen interaction physics which must be fully understood. As a new methodology, HIM is beginning to show
promise and the numerous potentially advantageous applications for nanotechnology have yet to be fully exploited.
NIST was fortunate to receive the first commercial HIM [2] and this paper will discuss some of the progress made at
NIST in improving its performance and to understand the science and capabilities of this new instrumentation. In
addition, it is the NIST goal to understand potential differences between HIM and contemporary scanning electron
microscope (SEM) instruments. Clearly, this is a difficult task since the SEM and the HIM appear similar in that both are
scanned particle beam instruments but are quite different in their overall operational parameters.
2. MATERIALS and METHODS
The scanning helium ion microscopes used in this work were either a Zeiss Orion Plus installed in the NIST Advanced
Measurement Laboratory or an engineering instrument installed at the Zeiss facility in Peabody, MA.
3. INSTRUMENT RESOLUTION
Imaging of the smallest details on a nanomaterial sample being viewed and then measuring it accurately is the goal of
both the NIST Manufacturing Engineering Laboratory’s Nanomanufacturing and Next-Generation Metrology Programs.
Understanding the overall behavior and performance characteristics of particle beam instruments (SEM and HIM) is
highly critical. For example, it is well known that at high accelerating voltages, particle beam instruments perform better
than at low accelerating voltage. There are a number of reasons for this characteristic difference [5]. In the SEM, low
1
Contribution of the National Institute of Standards and Technology; not subject to copyright. Certain commercial
equipment is identified in this report to adequately describe the experimental procedure. Such identification does not
imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the
equipment identified is necessarily the best available for the purpose
Scanning Microscopy 2009, edited by Michael T. Postek, Dale E. Newbury, S. Frank Platek, David C. Joy,
Proc. of SPIE Vol. 7378, 737808 · © 2009 SPIE · CCC code: 0277-786X/09/$18 · doi: 10.1117/12.824533
Proc. of SPIE Vol. 7378 737808-1