karlsuss2 users: please read

[Thomas O'Sullivan]

A follow-up on my note which will hopefully helps users decide how to 
proceed:
1)  Karlsuss2 and using the yellow-tape trick to cover a full wafer 
chuck produces similar (problematic) results
2)  Karlsuss1 does not show this problem for the piece chuck or the 
yellow tape - so that appears to be the way to go for now.

Thanks,
Tom

On 05/13/10 11:28, Thomas O'Sullivan wrote:
> Hi all,
> For the past 3 weeks, those of us who work with small pieces have been 
> unable to get a good (better than 5um) alginment on karlsuss2.  While 
> the mask appears aligned even when in contact (soft vacuum), after 
> exposure there is a ~5um random rotation causing an unacceptable 
> misalignment.
>
> We are trying to determine if this is a problem with the pieces chuck 
> itself.
>
> Has anyone experienced this problem when exposing full wafers?  Note 
> the shift is on the order of 3-5um, so you may not even notice if you 
> don't have that high of an alignment tolerance.
>
> Thanks,
> Tom
>
>