5 OPERATION
EM210F-1
5-29
5.3.3 Condenser Lens Astigmatism Correction
When astigmatism exists in the condenser lens, the shape of the electron beam when
converged maximally on the screen is elliptical and image brightness is insufficient.
Making the converged electron beam circle performs astigmatism correction.
1.
Select “Maintenance” on the “TEN Controller” main menu to display the
“Alignment Panel for Maintenance” screen.
2.
Insert a condenser aperture in the beam path.
3.
Converge the beam as small as possible using the BRIGHTNESS (L1-
⑥
).
4.
Depress the COND STIG switch (L1-
⑤
) or Depress the “DEF Select-CL
STIG” button on the “Alignment Panel for Maintenance” screen.
5.
Manipulate the DEF/STIG knobs (L1-
⑩
, R1-
⑤
) to make the beam circle
appearing just before and after the beam is converged.
?
When the BRIGHTNESS (L1-
⑦
) is turned slowly back and forth from the
position where the beam is maximally converged, the electron beam appearing
just before and after the beam is converged is elliptical if astigmatism exists in
the condensed lens.
5.3.4 Beam Deflector Adjustment
5.3.4a Tilt
adjustment
This is to adjust the ratio of the current in the condenser lens beam deflector upper coil
and lower coil so that the electron beam deviation when tilting the beam is minimum.
1.
Select “Maintenance” on the “TEN Controller” main menu to display the
“Alignment Panel for Maintenance” screen.
2.
Set the magnification to 10,000 times.
3.
Converge the beam as small as possible using the BRIGHTNESS (L1-
⑥
).
4.
Center the beam using the SHIFT knobs (L1-
⑧
, R1-
③
).
5.
Depress the “Wobbler-TiltX” button on the “Alignment Panel for Maintenance”
screen.
The beam spot is divided into two now.
6.
Depress the “compensator-Tilt” button on the “Alignment Panel for Mainte-
nance” screen.
7.
Make the divided spot a single spot using the DEF/STIG X knob (L1-
⑩
).
8.
Turn off the “compensator-Tilt” button on the “Alignment Panel for Mainte-
nance” screen by depressing the button.
9.
Center the beam using the SHIFT knobs (L1-
⑧
, R1-
③
).
10.
Depress the “Wobbler-TiltY” button on the “Alignment Panel for Maintenance”
screen.
The beam spot is divided into two now.
11.
Depress the “compensator-Tilt” button on the “Alignment Panel for Mainte-
nance” screen.
12.
Make the divided spot a single spot using the DEF/STIG Y knob (L1-
⑩
).
13.
Turn off the “compensator-Tilt” button on the “Alignment Panel for Mainte-
nance” screen by depressing the button.
