Policy on nanotubes, nanowires, etc.
John Ross Jameson
jameson at stanford.edu
Thu Oct 23 09:50:13 PDT 2008
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.
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?
> 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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