Today, ion beam etching is the most widely used method for preparing samples for electron microscopy. In this process, the sample material is bombarded with a high-energy argon-ion beam. The ion energy and the milling angle depend on the corresponding application.
For preparing samples for scanning electron microscopy (SEM), etching is used to improve or modify the quality of surfaces.
One can clean, polish or alter the contrast of these surfaces. The quality of the surfaces after the ion beam treatment is so good that they can also be used for surface sensitive methods, such as EBSD.
Another special application of ion milling involves the preparation of sample cross-sections using ion beam slope cutting.
The Leica EM TIC 3X is an ion beam etching unit that is used for preparing samples for scanning electron microscopy. Sample cross sections can be produced and larger surfaces can be processed.
The cross-sections can be treated again in an additional process using a low-energy ion beam. This applies both to cleaning as well as contrast enhancement.
Additionally, it is also possible to improve the quality of mechanically polished surfaces via a final ion polishing process. The maximum size of the processed sample surface is 25 mm in diameter, the maximum size of the samples to be processed is 38 mm in diameter.
The surface of samples can be cleaned, polished and have its contrast altered. This makes it possible for all preparation types for scanning electron microscopy to be carried out in a single instrument.
The instrument is setup in a modular system and uses 5 different samples stages for the respective applications: a standard stage, cooling stage, multiple stage, rotary stage and a vacuum lock to transfer cryogenic samples or samples sensitive to oxidation. These sample stages can be changed very easily.
The standard stage is suitable for a wide application of samples that have different sizes, shapes and material. Samples with thermal sensitivity are prepared in a special cooling stage to prevent the samples from being destroyed due to overheating. Finally, the multiple stage makes it possible to prepare 3 samples successively without intervention by the operator. This guarantees a high level of sample throughput.
The rotary stage can handle the surface treatment of samples that measure up to 38 mm in diameter. The preparation process and progress can be observed at any time using a stereomicroscope. As an option, images can also be stored using an integrated camera.
The TIC 3X is a compact tabletop instrument that combines all components in one housing. The instrument uses a unique triple beam technique. Three ion beams intersecting at the mask edge shape a milling sector of 100°. The instrument uses saddle-field ion sources
that together attain milling rates up to 300 µm/h at 10 kV and 3 mA.
The triple beam technique eliminates the need to move the sample during ion milling. This creates myriad benefits that will be discussed in greater detail below. All of these advantages guarantee a high level of preparation quality.