Large-Area High-Resolution Imaging
Challenge of High-Resolution SEM Imaging
Highest-resolution, accurate SEM imaging of “large samples” exceeding a single typical field of view (in the order of a few tens of μm) is a challenging procedure. A set of several hundreds or thousands of images have to be stitched together in order to display a surface spanning several millimeters or even centimeters as a “Google Earth”-style map. Any standard mechanical stage will have visible stitching errors, and thus yield distorted images.
The Raith systems are different: By reversing the functionality of a professional electron beam lithography tool, the sample surface is not exposed; instead, existing nanostructures are seamlessly imaged using the extreme placement accuracy of the tool infrastructure.
Users can benefit e. g. from the “on-board” Laser Interferometer Controlled Stage technology, related write field alignment functionality, and drift correction algorithms. These features deliver ultra-precise and fully automated image acquisition for generating highly accurate and undistorted “land maps” of large samples with highest resolution and stitching accuracy in the 10 nm range – and in 2D and in 3D in case several (sequentially deprocessed) layers are involved.
Reverse Engineering and Connectomics
Chip makers are not the only users to rely on Raith technology for reverse engineering applications and identification of counterfeiting or parasitic chips. Nanobiologists too, can use all these features to reveal the brain circuitry in connectomics. Here, analysis of the connectivity of neurons is the driver for (3D) brain mapping.
Images: Christine A. Brantner, et al., George Washington University