Raith: interesting (important?) discovery

James Conway jwc at snf.stanford.edu
Tue Jul 5 12:15:51 PDT 2005


Hello mark and RAITH Users:

This is the first report of this kind of problem.  Has anyone else seen 
this type of problem?

Please check your time delay settings to minimize dynamic effects:
In the exposure control box check DETAILS.  This is the time delay 
between stage moves and Write field to Write Field stitching moves 
between write fields.  Best value is 5 ms (default), but it is user 
adjustable and it may have been changed in the specific users' login.  
Times greater than 3 ms have been found to expose correctly.

Thank you,

JWC


Mark Topinka wrote:

> Hi-  if anyone is continuing to have problems with part(s) of their 
> pattern being blurry or not exposing at all, while the rest of it 
> seems fine, please contact me asap.  I think I've figured out a 
> work-around, even though I still don't understand the underlying 
> hardware problem.  As best I can tell, this is not happening because 
> of a leaky beam blanker.   Rather, it seems that after a long time 
> being blanked (like, between writefield moves), the beam is out of 
> focus and/or low in beam current  for the first roughly 0.01-0.1 
> seconds after being unblanked (+ or - a factor of ten, probably - I 
> haven't measured it carefully, and it probably depends on lots of 
> things).    Short blankings, like between dots or objects within one 
> writefield don't affect it, so after the initial "warm-up" time in 
> each writefileld, my experience has been that the rest of the pattern 
> writes great.  The (hack) solution that I found is to make a 
> sacrificial object in each writefield that takes about a second to 
> write and is the first thing that gets written.  (Use the "O" command 
> in the raith pattern editor to order your objects  so that it is the 
> first object written, otherwise it does no good).  I have no idea 
> *why* the raith is doing this.  Has anybody else continued to 
> experience these problems (even after the column replacement?) or have 
> I been the only one?  -Mark
>  





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