On Sun, May 23, 2010 at 6:30 PM, Andrea Mazzolari  wrote:
> Hi All,
>
> i would need a couple of informations related to mask aligners (Karl Suss,
> EVG, others ???)
>
> 1) For my application i would precisely align the mask features with wafer
> flat. Tipically wafers are loaded in a mask aligner and pre-aligned with a
> "flat finder" system. Which is the tipically accuracy of commercial
> mask-aligners in the alignment of mask to wafer flat ?

The bigger problem is, commercial wafers have at least a 1 degree
mis-alignment between main flat and crystallographic plane. I am
guessing that is much more than the tolerance of any aligner, and
hence it is your bottleneck. You might need to etch test trenches
along the edge, before alignment.