System FE-Gun alignment and adjustments have been performed. Users should encounter markedly better brightness and resolution.

James Conway jwc at
Wed Jul 16 18:08:24 PDT 2008

*Greetings SEM4160 Users:*

Responding to a swarm of unhappy User reports regarding brightness, a 
poor Secondary Electron signal to noise issue, and poor resolution in 
general I performed a mechanical FE-Gun alignment and redid all the 
column adjustments.  Users should encounter markedly better brightness 
and resolution.  Details are in the sem4160-pcs email attached below.

It is suggested that if you are not an expert operator to start your 
sessions at 10 mm Working Distance and begin at 10keV acceleration 
voltage using any aperture strip number to ensure you can obtain a 
suitable SEM image before changing any settings.

  The system is once again in Green light status on CORAL.  

Users desiring further support and assistance should visit me during my 
office hours.

Thank you for your interest in Ebeam Technologies here at the Stanford 
Nanofabrication Facility.


James Conway

-------- Original Message --------
Subject: 	Re: Problem sem4160 SNF 2008-07-16 11:45:53: Poor resolution 
and brightness
Date: 	Wed, 16 Jul 2008 16:53:32 -0700
From: 	jwc at
To: 	sem4160-pcs at

realigned the FE GUN using the four mechanical screws and then adjusted the column alignments.
Performed resolution test on Sn on Carbon stud at 300 and 100 kx magnification.  Ultimate resolution is 6 nm in X and 5.4 nm in Y at 300 kX magnification.
Brightness improved markedly after the FE-Gun realignment.

Optimized gun aperture alignment, movable aperture strip setting No. 4 for 10 - 11 mm Working distance at 10 keV Acceleration Voltage.
No other issues observed.
Users are asked to NOT translate or attempt to adjust the upper movable aperture plate which are the Beam Monitor apertures!
Only the lower movable aperture strip should be adjusted when doing aperture alignment.
Thank you for your user reports on this system.*

James Conway

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