[labnetwork] Resist coating of tiny pieces

[Michael Rooks]

How tiny are the pieces? When we do lithography on little diamonds, we use
crystalbond wax to stick them to silicon wafers, then we just drip resist
(pmma) over the diamonds. It's not very uniform, but it does the job.
Larger, flat, millimeter-range pieces can also be waxed to the center of
silicon wafers, without any etched recesses. Spinning resist will not
provide a very uniform layer, but it's usually good enough for e-beam.
Contact photolithography requires good uniformity; my advice is don't do
it. When the pieces are > 5mm then they can be spun just like tiny wafers,
with tiny spinner vacuum chucks. If the pieces have silicon nitride windows
then you can avoid the vacuum chuck by making a spinner chuck with a simple
recess, and no suction.


--------------------------------
Michael Rooks
nano.yale.edu


On Mon, Nov 16, 2020 at 11:45 AM Lino Eugene <lino.eugene at uwaterloo.ca>
wrote:

> Dear colleagues,
>
>
>
> We are having more users who work on tiny pieces to be coated with photo
> and e-beam resist.
>
>
>
> I am thinking of different ways to coat these pieces:
>
> ·       custom chucks with a recess of the size of the chip
>
> ·       Si carrier wafer with recess etched by SF6 plasma
>
> ·       MicroSpray photoresist
>
>
>
> I am wondering if you could share the techniques you use to get uniform
> coating on very small pieces.
>
>
>
> Best,
>
>
>
> *Lino Eugene, P.Eng., Ph.D.,*
>
> Micro/nanofabrication process engineer
>
> Quantum-Nano Fabrication and Characterization Facility
>
> QNC 1611
>
> University of Waterloo
>
> 200 University Avenue West
>
> Waterloo, ON, Canada
>
> N2L 3G1
>
>
>
> Ph: +1 519-888-4567 #37788
>
> Cell: +1 226-929-1685
>
> Website: https://fab.qnc.uwaterloo.ca/
>
>
>
>
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