New FAQ: Write Field Alignment Error: ZOOM U or V exceeds limits allowed...

James Conway jwc at
Wed Jan 19 10:03:39 PST 2005

Josh and other RAITH Users:


Write Field Alignment Challenges: What to try if you get a ELPHY+  Zoom 
U or V exceeds limits error:

If  you hit the limits first check your Working Distance (W).
If it is less than 5 mm  -  adjust W in the UVW Alignment Window then 
drive the stage to W = 5 mm (absolute) and repeat the write field 
alignment.  You should get results on the order of Zoom U =1.48 and Zoom 
V + 1.5248 at 600 X magnification for the 100 um write field specification

If you cannot complete the write field alignment  THEN reduce to 
magnification to 550 - 580 x and reset the write field alignment window 
to Zoom U = 1.0, Zoom V =1.0 and repeat the WF alignment feature.

I have been able to get to complete the procedure at 600 X on my user: 
jwc log in. The result although close to the limits my results after WF 
Alignment  do not exceed the limits of Zoom U or V > 1.55 . This is 
giving me superb results for stitching and overlay alignment on the system.

If you, or other users, are having continuing issues with this please 
call me. If I am in the lab, I would be happy to assist you. Today or 
tomorrow I will be testing the system in my user: test_user default user 
log in to ensure that the changes I made to the system settings were in 
fact transferred down to all current users on the RAITH 150.

Hopefully everyone will be able to obtain optimal EBL results on the system.

James Conway

Josh Ratchford wrote:

>Hi James,
>The Raith worked just fine for me last night and my patterns turned out to
>be the feature sizes I expected.  The only problem I had was with write
>field alignment.  The Raith prompted "Zoom (Y) would exceed limit",
>followed by "For a sucessful correction readjust SEM stage and reset ELPHY.
>I know we had a conversation in the past about the ELPHY but I have forgot
>the details.  Could you please enlighten me?
>Thank you,
>P.S.  I thought I wouldn't like suiting up to use the raith but after last
>night I found it more convienient to have access to the clean room rather
>than the john.
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