Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

Abstract. Grain size determination in advanced metallization structures requires a technique with resolution ~2nm, with a high signal-to-noise ratio and high orientation-dependant contrast for unambiguous identification of grain boundaries. Ideally, such a technique would also be capable of high-throughput and rapid time-to-knowledge. The Helium Ion Microscope (HIM) offers one possibility for achieving these aims in a single platform. This article compares the performance of the HIM with Focused Ion Beam, Scanning Electron and Transmission Electron Microscopes, in terms of achievable image resolution and contrast, using plan-view and cross-sectional imaging of electroplated samples. Although the HIM is capable of sub-nanometer beam diameter, the low signal-to-noise ratio in the images necessitates signal averaging, which degrades the measured image resolution to 6-8nm. Strategies for improving S/N are discussed in light of the trade-off between beam current and probe size, accelerating voltage, and dwell time.