
3.4Optimizing the Electron Beam
3.4.1Selecting a Magnification Mode
High Mag Mode (HM) | : | × 300 to × 800,000 |
(The lowest and highest magnification will be changed depending on present | ||
accelerating voltage and working distance) | ||
Low Mag Mode (LM) | : | × 20 to × 10,000 |
Use the High Mag mode for usual observation, and the Low Mag mode for field searching.
Electron optical column conditions are set for both modes independently.
3.4.2Selecting Electron Optical Column Condition
Electron optical column conditions need to be selected before alignment and operation of the SEM begins.
For High Mag mode, use the
For Low Mag mode, use the Column tab of the Setup dialog window .
3.4.2.1 High Mag mode
Items need to be set frequently are placed on the
Probe Current mode selection box
Focus mode selection box
WD(Working distance) set / indicate box
WD range indication
Condition Load / Save button
Setup button
(1) Probe Current mode
Select Normal or High in the Probe Current mode selection box. Normal is for high resolution image observation. Use High for applications needs large probe current, such as EDX analysis.
(2)Focus Mode Select UHR or HR.
In UHR mode, full working distance range is available. At working distance range longer than about 8mm, the mode may cause somewhat rough focusing feeling.
In HR mode, working distance range is limited to about 5mm or longer. The mode is easier to use at long working distance.
(3)Working Distance (WD):
Working distance (WD) is the distance between the bottom face of the objective lens and the
3 - 15