raith clip #4 is very dirty
jwc at snf.stanford.edu
Tue Jun 27 09:27:24 PDT 2006
Hello Raith Users:
Once again we have had the return to a single user, or group of Users,
whom have some material on the back of their wafer pieces. This
material is incompatible with the Aluminum pallet and it is rapidly
anodically corroding its surface where they are clipping down their
samples. Often they are working with multiple very small samples on
several clips in the system.
It is difficult if not impossible to remove as it smears when you
mechanically attempt to clean it off, and is not affected by solvents.
Likely this is Gallium or Indium metal that a MBE or MOCVD system User
may have used to attach his wafer to the growth mount in those system.
These are all small pieces of substrate often smaller than 4 x 3 mm.
The end result is that it contaminates the Std. sample holder, roughens
and corrodes the surface and then renders the Std. Sample holder
unsuitable for EBL because the holder cannot make suitable electrical
contact to the sample nor allow it to lay flat onto it.
THIS CARELESSNESS IS NEGATIVELY IMPACTING EVERYONE WORK. HOW CAN ANYONE
BE SO STUPID?!!
All Users working with any material on the back sides of the wafers are
instructed to completely remove all material before placing the sample
into the RAITH.
This includes resist and PMMA residues as well as all residues from
previous processing and mounting of your samples on the backside of your
chips and wafers.
Users having concerns or needing assistance in cleaning their samples
are requested to contact James Conway for help.
Thank you for your support!
Andrei Faraon wrote:
> Hi James,
> Today around 9:30 when I came to do my Raith lithography and I noticed
> a big grey-colored stain under clip number 4. It looks like the same
> material that made the other clips dirty. However, this stain is very
> large, on the order of ~1cm/1cm. Maybe you could re polish the stage
> during the Raith shutdown next week because all the clips are in
> pretty bad condition, especially for people working with small pieces.
> Andrei Faraon
> Stanford University, Applied Physics
> 316 Via Pueblo Mall
> Stanford, CA, 94305
> Mobile: 650 714 7881
> Office: 650 723 2279
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