SIM：Scanning Ion Microscope
Features.
Secondary electrons are generated when a solid sample is irradiated with an ion beam.
Secondary electrons produce dark and bright image regions depending on the orientation of each crystal grain. The resulting image is called scanning-ion microscopy (SIM) image. Electron beam irradiation also produces images, but ion beam images have higher contrast is more pronounced. It is possible to obtain information on the size and distribution of crystal grains in metal polycrystals. Features include:
- High spatial resolution (4 nm at 30 kV acceleration voltage)
- Information on the polar surface layer (more than SEM image)
- Observation of metal grains, e.g., Al, Cu
In addition, the SIM equipment at MST has the following characteristics:
- Support for standard wafers up to diameters of 300 mm.
- Acquisition of successive cross-sectional SIM images in conjunction with focused ion beam (FIB) processing ("Slice &View").
Application Examples
- Visualization of conductivity in cross-sectional regions (conductive contrast)
- Observation of crystal grains in Al, Cu, Fe, and other metals (channelling image)
Principle
The sample surface is scanned by a beam of Ga ions that is focused to a submicron diameter. Upon radiation of the sample, secondary electrons are emitted from the surface, which are detected and imaged.
Data Example
In poly-crystalline samples of metals, such as Cu, the image grey level depends on the crystal grain orientation as shown in Fig. (channelling contrast image). Channelling contrast images can be seen even with electron irradiation. However, Ga ions produce images with higher contrast, though the spatial resolution is smaller compared to electrons. Due to the higher contrast, SIM is more suitable for observation of crystal grain boundaries in metals such as Al and Cu.
Data delivery format
- Tag image file format (TIFF) and/or joint photographic expert group (JPEG) files
Specifications
Items for enquiries
- Purpose and contents of measurement
- Sample information
・ Number of samples, and availability of preliminary samples
・ Shape, dimensions, layer structure, film thicknesses, expected composition and surface roughness of the outermost surface, availability of cutting the sample, desired regions of interest (ROI) and observation points
・ Handling instructions
- delivery date
- Details on delivery
・ Preferred due date for preliminary analysis report
・ Due date for delivery of final report
- Any other issues
Caution
Contact MST in advance to verify the compatibility of sample dimensions.
Click here to see a case study of the [SIM] scanning ion microscopy method.