Thin section lift-out refers to a sample preparation technique that is usually carried out in FIB-SEM.
It makes use of the capability of material milling by the ion beam, and also the GIS and nano-manipulator, to prepare thin lamella that can be imaged in TEM or the transmission mode of SEM.
Compared to ultramicrotomy, this is site-specific and beneficial for certain materials, e.g. the geological samples.
The process starts with preparing a thick section (relatively compared to the final thin section) by milling two large cavities, then in-situ deposition is used to weld the section with the tip of nano-manipulator attached to the top surface.
Then the section is cut free to be mobile with the manipulator so that it could then be welded to a special holder grid.
Once the thick section is welded with the needle-like manipulator, it could be then attached to a special grid of the shape like a half moon.
Again, it's fixed by GIS welding and then cut free by FIB milling.
The final step is then to thin down the fixed thick section on the grid to the desired thickness by gentle ion beam polishing.
For this reason, it is normally recommended to have a protective layer deposited on the top surface of the thick section.
With the ability of SEM imaging while ion beam milling, the thinning process can be monitored lively to make certain of the section's quality.
