Policy on nanotubes, nanowires, etc.
mtang at stanford.edu
Thu Oct 23 08:31:51 PDT 2008
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,
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