Subject: Re: hi, please help NEW THREAD NAME ---> FAQ NO 1: How to improve your SEM imaging and see the features on the CRT clearly...
From: "James W. Conway" <jwc@snf.stanford.edu>
Date: Tue, 18 Sep 2012 11:18:33 -0700

HI Kathy,

Thanks for giving it your best efforts!

This is a common issue with many users so lets make this thread now called --->  FAQ NO 1: How to improve your SEM imaging and see the features on the CRT clearly


Getting acceptable SCREEN resolution likely is a result of your scanning speed during image acquisition.  The higher the scan speed Number i.e., speed 1 to 2, followed by No 3 to 4 the more dwell time per pixel gives you more information and the image appears denser and with reduced signal to noise levels. 

If you are not getting enough signal, first reduce brightness and then increase contrast to a level just below where noise becomes more apparent.  You can also set the contrast to between 20 and 80% using the monitor function button. Contrast in the monitor signal is the width between high and low peaks in the waveform and brightness is the relative position of the waveform.  Best focus is obtained when the waveform appears the most  jagged with narrowest peaks.

The five lines from bottom to top are 0, 20, 50, 80, and 100% brightness respectively.  So I will set the contrast to go from 20 to 80 % brightness in the waveform display using the monitor function.
I often set this up using a particle or any feature found in the field of view.  If you still need more signal change to the next larger Aperture Strip hole position on the moveable aperture.  Default is Aperture No 3 and for very high resolution aperture strip No 4.

On the other hand,  very likely in your case if you are imaging resist or oxides, if your sample is charging it will appear fine at lower magnifications -- but as you zoom up in magnification details become lost and often a very dark image appears or seems to be distorted as the sample surface charges up.  The only solution for this is to image at low acceleration voltages or to coat your samples with a thin conductive film of metal. ( 40 angstroms of Cr or W, 100 - 150 angstroms of Au, Pd, or Al, or any other conductive metal.  We are getting our Hummer sputter coater set up and should have it ready for use shortly.

I am happy to assist you if you are around today.  Please see me in my office free until 4 PM ...

James Conway

On 9/17/2012 9:40 PM, kj.jackson@comcast.net wrote:
Hi James,

I went to use the sem4160 tonight and was not having any good results getting screen resolution.
Would you please be able to give your good going over to align it again.


I need to use it again tomorrow night and would really appreciate the help.
thank you so much
Kathy Jackson
408-888-7884


i did try