running auto alignment first select an area on the sample or sample holder that has
homogeneous brightness at moderate magnification (1-5 kx) to get the best beam
alignment.
18.
Select a spot size, usually initially between 30 and 40. Click
to
get dialog box with slider control. Usable range is about 10~75.
19.
If desired, chose a pre-defined
Recipe
to set microscope conditions
(you may
switch to LV mode by selecting an LV recipe). This is a very good way to set
appropriate SEM parameters if you don’t know what you want.
Select the desired recipe and click execute.
20.
Click
View
{sets fast scan (same as Scan 2) at very low magnification (30X)}.
At this point, you could also select Scan 2 and move stage to area of interest an select
a relatively low magnification (features still visible although they may be out of
focus).
21.
Click
ACB
(auto contrast brightness).
22.
Focus and check the objective aperture centering
, especially for high
magnification work.
23.
Fine focus and correct the astigmatism the image manually
or click
Auto Focus
or
Auto Stigma
(auto focus and auto stigmator). On many samples
auto focus and auto stigmate actually will fail or will not be exact. Usually you need
to manually focus and stigmate especially at higher magnifications.
Almost always
you need to fine tune focus and stigmators manually!!
These functions are, of
course, available on the knob pad. You also need to check and, if needed, adjust the
objective aperture centering
. See the next step and individual procedures in the rest
of the manual for details on how to perform these operations.
24.
Observe your sample
a.
If the image shifts when manually focusing, align the objective aperture.
Adjusting this will always cause the astigmatism correction to change!
b.
If the image focuses asymmetrically or with stretching or streaks, correct the
astigmatism.