AVS 62nd International Symposium & Exhibition
    Helium Ion Microscopy Focus Topic Thursday Sessions
       Session HI+AS+SS+NS-ThM

Invited Paper HI+AS+SS+NS-ThM3
Nanofabrication Using Gas-Assisted Focused Ion Beams

Thursday, October 22, 2015, 8:40 am, Room 211B

Session: Focused Ion Beam Technology (08:00-10:00)/Fundamentals of Helium Ion Microscopy (11:00-12:20)
Presenter: Chad Rue, FEI Company
Correspondent: Click to Email
A brief introduction to gas-assisted etching for Focused Ion Beams (FIBs) is given, including typical chemical precursors for various applications, and appropriate beam control parameters such as pixel overlap, dwell time, and refresh time. These factors are reasonably well-understood for pattern dimensions that are large compared to the size of the ion beam. However, for applications such as nanofabrication, which require high milling precision over small areas, the limiting size of the ion beam and its associated activated volume begin to influence the milling performance. The remainder of the discussion will focus on the relatively-unexplored regime in which the size of the pattern dimension is comparable to the size of the ion beam itself. The influence of various beam control parameters, particularly refresh time, becomes critically important to the milled profile of the desired structure. Redeposition effects, peripheral erosion, and mill rate trends are discussed. Operating tips and tricks are described, including the use of drift compensation strategies. The minimum physically achievable via size is examined. For a 10 pA Ga+ beam at 30 keV, used to mill a via in a SiO2 substrate with XeF2-assist, the minimum achievable via size (FWHM) is found to be 50 ± 10 nm, and is relatively independent of depth or aspect ratio. Implications for nanofabrication are discussed and examples are shown.