Policy on nanotubes, nanowires, etc.

John Ross Jameson jameson at stanford.edu
Thu Oct 23 09:50:13 PDT 2008


Hi Mary,

Thanks for the quick reply.  I'll wait to hear about the ASML policy
before I do anything.  I would note, however, that the nanotubes would
be completely covered with photoresist by the time they reached the
ASML.  The only issue I could see, then, is that there could possibly
be stray nanotubes on the backside of the wafer, if the nanotubes were
spun on in a sloppy way.

Thanks,
John

On Thu, 23 Oct 2008, Mary Tang wrote:

> Hi John --
>
> Our policy on nanotubes has been that:
>
> 1.  Conducting and semiconducting nanoparticles and nanowires cannot be
> spun in from solution inside the lab.  This is to prevent
> cross-contamination of other people's work, since spin coating
> aerosolizes the solution.  Ordinary latex nanoparticles are OK on the
> headway, because they are non-conductive and can be dissolved like most
> resists.  We have a rather crude spin coater outside the lab which is
> available for spin coating of conductive materials.  There are some
> nicer ones in CPIMA, MatSci and ME labs.
>
> 2.  Wafers with nanoparticles and nanowires adhered to them can
> generally be processed as "gold-contaminated" substrates.  As you say,
> van der Waals holds them down through most processing, including spin
> coating with photoresist.  So, the processing you propose should be fine
> for the most part.  The only question I have is with the ASML.  As you
> know, the ASML system belongs to ASML, and they have the final word as
> to what kind of materials are OK to process in their tool.  Ed -- have
> nanotubes been OK'ed on the ASML?
>
> Mary
>
> John Ross Jameson wrote:
> > Dear SpecMat,
> >
> > I'd like to do some processing of carbon nanotubes and nanofibers
> > in SNF, and I've gotten different answers about what is allowed
> > and what isn't.  What I'd like to do is bring wafers into the fab
> > that have carbon nanotubes or nanofibers sitting horizontally on
> > the surface.  The nanotubes/fibers would only be held on by van der
> > Waal forces.  That is enough to keep them from blowing off, but
> > not enough to keep them from being rubbed off.  I'd like to do a
> > lift-off process to pattern metal on top of the nanotubes/fibers,
> > using either the ASML or EV aligner.  For the metal dep, I'd use
> > the innotec or metalica.  The lift-off could be done at SNF, or
> > elsewhere if necessary.
> >
> > Would this process be OK to do in SNF?  Do I need to check back with
> > you if I decide to try another type of nanotube/wire?
> >
> > Thank you,
> > John
> >
> >
> >
>




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