Zeiss GeminiSEM Series, Instruction Manual

Page: 111 / 164

ZEISS 5 Commissioning and First Operating Steps | 5.8 Working with Variable Pressure
à
The stage is moved down to give space for the beamsleeve to be inserted.
à
The beamsleeve is inserted under the objective lens.
à
The turbo pump isolation valve is closed and the gas flow valve is opened to introduce
gas into the chamber.
à A leak test is done at 30 Pa to check for vacuum tightness of the beamsleeve.
à
The EHT is turned on again, if it was on before the transition.
3. Wait until the system is ready for VP operation and Chamber Status = At Nano VP or
Chamber Status = At XVP is displayed. This takes approximately 60 s.
à
The transition is indicated in the status bar of the SmartSEM software.
à The system sets the chamber pressure to the value displayed in the VP Target field. If
you have not changed it, it is the value of the last VP session.
4. To change the chamber pressure, use the VP Target scroll bar.
Alternatively double-click into the VP Target field, enter desired pressure value and click
OK .
Refer to Working with Variable Pressure [
}
103] to determine the correct pressure value.
5.8.3 Returning to HV Mode
HV mode is the standard mode of a FESEM. It offers the possibility of analyzing and mapping con-
ducting specimens. In HV mode, the pressure in the specimen chamber is less than 10⁻⁶ mbar.
Info
When switching from VP to HV mode, the column chamber valve closes automatically, as a rel-
atively poor vacuum is available in the specimen chamber when opening the TIV.
Prerequisite
ü
The microscope is operating in VP vacuum mode
Procedure 1. In the GeminiSEM Control panel, select the Control tab.
2. In the
Variable Pressure section, click HV to start the pre-defined macro.
The macro automatically performs the following actions:
à
If EHT is on, it is turned off.
à
The column chamber valve is closed.
à
The gas flow valve is closed and the chamber is pumped down to 15 Pa.
à The turbo pump isolation valve is opened.
à
The stage is moved down.
à
The beamsleeve is retracted.
à
The EHT is turned on again, if it was on before the transition.
à The transition is indicated in the status bar of the SmartSEM software.
This takes approximately 60 s. If the chamber pressure was really high before, then it
takes a little bit longer.
Instruction Manual ZEISS GeminiSEM series | en-US | Rev. 2 | 349500-8138-000 111