Alignments: E-Column: Supervisor Alignments
4-11
C O N F I D E N T I A L
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User Manual
Revision A
Feb 2018
Source Tilt & Shift
This procedure takes from 2 to 3 hours and should be executed when necessary. It centers the electron beam in the
column using three variables:
•
DPA
(Differential Pumping Aperture – separates the high vacuum column part from the chamber vacuum) –
centers the electron beam to pass through the column without any cutoff.
•
Tilt
– centers the beam on the optical axis.
•
Shift
– centers the beam on the center of the final lens.