Download Short user guide for scanning electron microscope (SEM)

Short user guide for scanning electron microscope (SEM)
Instrument: XL30 ESEM TMP (FEI Company, The Netherlands)
HIGH VACUUM OPERATION
Introduction:
Conventional high vacuum mode is used for dry and conductive specimens.
Secondary electrons are detected and used to form an image.
Lowest magnification about 20 x.
Start up procedure:
Typically no specific preparations are needed to use the instrument in high vacuum mode. The
system should always be ON, i.e. control software and vacuum pumps are operating.
Switch on the monitor if needed and localize Microscope Control software (should be on)
Open the valve of the nitrogen gas bottle for enabling ventilation of the vacuum chamber.
Inserting specimens in the chamber
Check in the software that the acceleration voltage is off; kV button in the Beam panel is grey
Press the Vent button and wait for a while so that nitrogen gas fills the vacuum chamber; Open
the vacuum chamber door by pulling the handle.
Insert your specimen stubs on the specimen stage by using special forceps.
- When using stage for 7 specimens, please note the stage vs. monitor orientation difference
- Set the height of the stage so that the inspected surface is at 10 mm (from the lower end of
the OL cover). Use the measure tool for determining the height (= working distance, WD).
Close the chamber door,
Check from the Settings/Vacuum panel that HiVac mode is chosen. Check also that hand
operated valve is in “Hivac”.
Press the Pump button and wait for a while so that VacOK appears in the Vacuum panel.
Generating an image
Press the HT button in the front panel of the equipment (if not ON)
Press the kV button in Beam panel to generate electron beam (kV button turns yellow)
Image should appear in the software and if not
- Use brightness and contrast controllers in the software to achieve an image
- Choose low magnification from the Magn menu (e.g. 50 x)
Please note the appearing warning box; you should check the image focus before clicking OK!
- Focusing the image; press the right mouse button (a double arrow appears) and while the
button is depressed move the double arrow to left or right. When the image is in focus,
release the right mouse button.
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Moving the specimen during imaging
Tools for moving the specimen are found in the top row of the software. Typically are used:
Get – a spot moves to the center of the image are after doubleclickking the spot on the
image.
Track – for surfing around by pressing the left mouse button and moving to various
directions while mouse button is depressed.
When changing to another the specimen on the stage, enlarge the Stage panel in the software
and double-click the desired specimen location.
sample stage moves “in large scale”
Changing the magnification
Choose the Magn menu and select the desired magnification
- Hint: You may also change the magnification easily by pressing (+) or (-) signs in the
keyboard: (+) sign doubles the magnification ans (-) sign halves the magnification
(i.e. 200x 400x or vice versa)
Issues affecting the image quality
Scanning speed; can be selected from the Scan menu. Typically Slow Scan 1 is used (i.e. 0.21 ms
scanning time/line and 484 lines/image)
TV-scanning speed can be chosen from the tool panel in software (fast update but
grainy image)
Image averaging; can be selected from Filter menu. Typically used values 2 or 4. (I.e. 2 or 4 images
are used to generate the live image). Image quality is better but the image updates slowly.
Acceleration voltage; you may change the acceleration voltage during live imaging by choosing
Beam menu
desired value for acceleration. Higher resolution could be achieved by higher
acceleration voltage. However, some specimens do not tolerate high energy electron beam.
Spot size; from Beam menu you may choose alternative spot sizes for the electron beam. Typical
values 3-5 (arbitrary units). The smaller the spot size the better resolution could be achieved. But at
the same time less signal is generated, especially noticeable during live imaging.
Capturing an image
Check image focus by pressing the right mouse button and moving the mouse
- Hint: Sometimes it’s better to check focus with higher magnification
Adjust brighness and contrast for each image by using controllers.
- If help is needed, choose a videoscope tool
- Adjust brightness and contrast so that the signal (curve) is located between
ESEM User guide
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the horizontal lines of videoscope. Try to achieve high amplitude (contrast) in the middle
level (brightness). Get rid of curves by clicking videoscope tool again.
Press F2 button in the keyboard to generate a slow scan image
- Slow scan image has higher quality than live image.
- Slow scan is “frozen” in the display for saving.
Choose In/Out menu
Image for saving the image file.
- You may add additional information to the image scale bar by selecting In/Out
Databar
and typing the information to User.
- Locate your personal folder from the hard disk; typically C:\XL\USR\[your name]. Save the
image file in .tiff format by typing the desired file name and clicking Save.
- NB! Only 8 characters is allowed for the file name (old WinNT OS!)
Finishing the operation
Switch off the acceleration voltage; press the kV button (in the Beam panel) so that it turns grey
Take your specimen(s) out from the vacuum chamber:
- Ventilate the vacuum chamber by clicking Vent button (in the Vacuum panel)
press OK
for the appearing window
- Wait for a minute so that pure nitrogen fills the vacuum chamber and open the chamber door
- Take your specimen(s) by using forceps and close the chamber door
Press the Pump button (in Vacuum panel) and wait the sign VacOK
If you are the last operator for the day, please follow the procedure:
- Enlarge the Vacuum panel and click the Rpm 60% button so that it turns yellow. (Then the
vacuum pumps do not operate at full power and they last longer)
- Close the nitrogen gas bottle
- Press the HT button in the front panel of the instrument
ESEM User guide
16.05.2012