High resolution specification of a Scanning Electron Microscope is traditionally defined by
visual separation of two gold grains on a carbon substrate. In order to achieve this a very high
magnification is used (above 400 000×), that will give some image noise but allows clear
measurements between the two respective particles. Although this method has been used for
decades it remains extremely subjective to interpretation.
In order to assure high standards in the FEI factory system assembly and test procedure, FEI
has defined a new process of high resolution specification determination that aims at
removing the subjectiveness from the final assembly and test procedure. The process is as
follows.
1. FEI Application specialists produce representative high resolution Gold on
Carbon images. These images are typical of what our applications specialists
believe are images that contain the resolution specified for the instrument in
question, based on visual separation inspection.
2. The sharpness of the gold grain edges in the reference images is measured with
FEI software. This program calculates the resolution across the edge of all gold
grains in the image. The edge resolution depends on the contrast threshold
values set in the program. An example of a threshold setting is 35/65. Threshold
35/65 was found to produce resolution values that correspond best to the
resolution values determined by the visual separation method.
3. For the system acceptance test, collect high resolution images from the
instrument and measure them with the software (threshold 35-65) – press
Ctrl+R. If the outcome of the calculation is equal to or less the value of the
specification in table below, then the system passes the high resolution test.
Proper measurement must consist the image quality evaluation (CTRL-Q) that
assesses how reliable the measured resolution is. The values must correspond
to following:
a. Clipping < 2%
b. Resolution measurement > Valid
4. System (chamber and resolution specimen) has to be clean without any
contamination. If not clean chamber at first, then clean specimen. Contamination
significantly degrade resolution especially at low kV.
5. High resolution image should be taken under chamber vacuum 10-3 Pa.
6. If needed, use plasma cleaner to clean the chamber to avoid contamination
during hires imaging.
7. Avoid sample plasma cleaning as it may damage your sample.
8. Put the resolution sample (S1987) to the heater (upper position)
貨物類號：Scios
貨物庫存：本商品現貨庫存3PCS
貨物貨期：到中國80-320工作日，全球DHL送達260工作日。
貨物儲存：NL