FEI Scios 2, Руководство пользователя

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Operating Procedures : Optimizing Imaging
C O N F I D E N T I A L – FEI Limited Rights Data 5-18
Column Use Cases
The electron column can be operated in different Use Cases
optimized for specific applications. To select desired Use case
use the toolbar /
Use Case module drop down list box.
You can immediately switch from one Use Case to the other. If
high voltage or beam current is out of the operating range of the
new Use Case, it sets automatically to the closest possible value.
If the newly set conditions do not allow imaging, (e.g. it is not
possible to focus), transition is not allowed and warning is shown
in the application status window.
In the OptiTilt and OptiPlan Use Cases primary electrons are
accelerated by the potential of the Acceleration tube (A-Tube)
and pass through the column at high energy. They are
decelerated back in between the T1 detector and the sample.
Secondary as well as backscattered electrons are also collimated
into the final lens by the A-Tube electrostatic field and detected
by the Trinity detectors (T1, T2, T3).
• Standard
This is the survey and TEM sample preparation mode. It is
ideal for navigating and reviewing sites at lower
magnifications. The A-Tube is on the ground potential and the
default detector is the ETD in the Secondary Electron mode.
Maximum probe current is limited to 13 nA.
Note

For detailed Cross section preparation workflow see the Help menu /
User Guidance item / Cross Section preparation.
• OptiPlan
This mode is used for ultrahigh resolution electron imaging of
the sample at short working distances (1 – 2 mm). The A-tube
is at the highest potential and the T1 and T2 detectors should
be used. Full range of the Beam Deceleration mode (if
installed) is available for this Use case.
• OptiTilt
The OptiTilt Use Case is optimized for operation at eucentric working distance. It is ideal for FIB cross section
preparation and subsequent ultra-high resolution electron imaging at low accelerating voltages. The A-Tube is
on the high potential, the T2 or ETD detectors are used to obtain topographical images and T1 to gain the
composite information. Small positive stage bias to improve the image quality is applied automatically when the
stage is tilted.
Note

For detailed high resolution electron imaging see the Help menu / User Guidance item / High Resolution Imaging.
Model difference
The LoVac mode can be used only with OptiPlan and Standard Use Cases.