3.2 Set a specimen
3-6
3.2 Set a specimen
3.2.1 Caution on specimen preparation
Note the followings descriptions while fixing a specimen to a specimen stub.
NOTE:● Do not touch the specimen or specimen stub with bare hands. Make sure to wear
clean gloves for handling. When sebum is adhered to the specimen or specimen
stub, it can cause of contamination.
● Make sure to select appropriate specimen stub size. If the inappropriate specimen
stub size is selected, the specimen cannot be protected properly, and it can cause of
damaging the specimen or instrument.
● When double-side conductive tape is used for fixing the specimen, cut the tape to
the minimum size. However, the FOV can be drifted during the SEM observation
when fixing a specimen with the double-side conductive tape.
● When conductive paste is used for fixing a specimen, use the minimum amount of
paste. Too much paste can release a large quantity of gas into the vacuum, which
can cause the contamination. Ensure that the paste has dried enough before setting
the specimen to the specimen chamber.
● Blow excessive powder of specimen with a blower after sprinkling the specimens on
the double-sided conductive adhesive tape. The unfixed specimens contaminate the
column and can cause of image deterioration.
● The moisture or oil contained the specimen will contaminate the column. Minimize
the amount of water and oil and set the specimen on the specimen chamber.
NOTICE:● In case of observing an insulating specimen with a project part (Dielectric
material) or a field-emitting specimen (such as a carbon nanotube), the specimen
may discharge due to the electric field of objective lens.
The scintillator of Middle detector can be damaged, and observation will not be
performed when the discharge is occurred repeatedly. Thus, to observe with
WD=6 mm or more is recommended for observing the specimen which is
mentioned as above.
If the specimen is discharging when setting the WD at 6 mm or more, set the
probe current at smaller value (set spot intensity at smaller value) or fix the
specimen with conductive paste or perform metal coating for the insulating
specimen with projection part (Dielectric material). Whereas, for the
field-emitting specimen, re-consideration of the fixing method is required.
The field emission can be suppressed by fixing the specimen surface evenly when
observing a carbon nanotube. In addition, the specimen can be fixed to be flat by
fixing it with conductive tape or paste and lightly press from the top, dispersing it
into solution and dropping it on the base then, drying it out, or removing the
uneven part while observing with an optical microscope.
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