Seeing is Believing

Microscopes have been an integral part in the development of modern science and medicine by providing a closer perspective to witness phenomena on a microscopic level.  The technology behind them has also grown immensely, with the current scanning electron microscopes and helium ion microscopes able to gather images at a resolution of 1 nm; however, a major drawback behind these microscopes are that they do not provide good quality when trying to scrutinize matter that is not a good conductor of electricity and they can cause damage to samples via the high energy required to power the beams.

Comparison in resolution between LIB microscope (left) and SEM microscope (right) in lead and tin components.

Comparison in resolution between LIB microscope (left) and SEM microscope (right) in lead and tin components.

Enter researchers from the National Institute of Standards and Technology who have developed an answer to the flaws of the SEM microscope by proposing an alternative low-energy focused ion beam. The suggested microscope would reduce the amount of electron volts from 30,000 eV to 500-5,000 eV by cooling neutral lithium gas to 600 microkelvins, slightly above absolute zero, using lasers and magneto-optical traps to hold the atoms in place. The next step is to accelerate the atoms by ionizing them and then changing the electric field.

In comparison to the microscopes used today the resolution of low-energy focused ion beam microscope is less than SEM and HIM microscopes for most samples, but for nonconductive materials the picture is more defined. Another possibility that can be explored is using a different element other than lithium within the microscope, with up to 20 other elements that could be potentially used.

A specific use in the near-future for this microscope could be to analyze silicon chips. These chips are essential in electronics programming and they are made by stenciling patterns via nanoimprint lithography. Before they can stencil the silicon, manufactures  must make sure there is not residue that could interfere with the pattern. SEM and HIM microscopes utilize too much energy and would damage the silicon, but the low-energy focused ion beam could get the job done. Although the current applications are limited to a small range of uses, the technology behind the LIB microscope is promising for future microscope developments and for the ability to look at things that are too small for us to see now.

For more information visit: http://www.sciencedirect.com/science/article/pii/S0304399114000679

 

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