4.MAINTENANCE
4.1Maintenance of Electron optical Column
4.1.1Maintaining Vacuum of Electron Gun and Intermediate Chamber
The electron gun shall be continuously evacuated. Keep ion pump power supply ON even when SEM is not operated.
If ion pump vacuum degraded than the following value, perform gun baking. Refer to <4.10 Gun Baking operation>
IP1: 2 ×
IP2: 2 ×
IP3: 5 ×
4.1.2Replacement and Cleaning of Objective Lens Aperture
Contamination of the objective lens aperture plate may cause increase of astigmatism or poor resolution especially at low accelerating voltage.
To replace or clean up the aperture plate, use following steps.
If you use low accelerating voltage and high magnification condition, coating with
(1)Turn off high voltage.
(2)Press down the S.C. AIR switch on the evacuation control panel 3 second or longer. The lamp of the switch will begin blinking. If aperture heater was ON, 30 minutes wait time for cooling down begins. While the cooling period, the Numeric / Character display on the panel indicates APXX (XX is rest of wait time in minutes). After cooling time ha passed, TMP will
be shut down and air introduction will begin. It will take about 10 minutes.
NOTICE
Wear gloves for the following steps. Do not touch to parts inside of vacuum area with your hand directly.
(3) Place aluminum foil of about 20 × 20 cm on a table.
All parts to be removed in the following steps should be placed on the foil.
