Hi,

I'm not sure who would be interested in buying a cheap makeshift spin-coater since you cannot get anywhere with just that, and it's super-easy to make yourself. For somebody who wants to make their own chips, a much more interesting target would IMHO be a development board for the DMD chip, even if it is nothing more than power, capacitors and a pin header for everything else. The DMD chip has an LGA package, and another one I found at TI has a PGA package, so that's a bit tough to solder by hand. There are dev boards available, but they are basically a simple projector (e.g. including optics) [1] -- maybe it is possible to modify that instead of a full projector.

[1] https://www.mouser.de/ProductDetail/Texas-Instruments/DLPDLCR2000EVM?qs=BZBei1rCqCAQetmBz0G1xQ==

Anyway, I can't tell you the model of the fan/motor since it is one of the case fans of the DLP projector I took apart. I'm pretty sure that I can get a better PC case fan for 2€ at the next supplier for computer parts.

WRT financing, let me repeat that I'm willing to spend money on even the simplest chips, at this point even a single MOSFET, if they prove that the whole idea isn't vaporware. I'm pretty sure we can find more people that feel the same when the first actual device gets posted to Hackaday and similar sites. Also, a Patreon site like [2] may help, but again, only if you can actually present something working (that guy can't). I think Sam Zeloof neglected this too much and didn't give people an easy way to send him money, because I'm convinced he would have gotten a lot of it.

[2] https://www.patreon.com/user?u=14363159

Greetings,

Martin

On Fri, Apr 30, 2021 at 2:52 PM David Lanzendörfer <leviathan@libresilicon.com> wrote:

Hi
So I've now set up the office here with tables and stuff and could reproduce
your experiments.
If we know which motor performs ok for building a cheap spin coater, I could
actually build one a little bit more professionally, by ordering some of those
motors from Aliexpress.
We could then sell those coaters on eBay and finance LibreSilicon
a bit with it.

What do you think?

Cheers
-lev

On Wednesday, April 28, 2021 6:36:11 PM WEST Martin Geisse wrote:
> Hi,
>
> > If I remember correctly the spin coaters used in clean rooms first spin
>
> up the wafer and then dispense the liquid
>
> That did the job. I still think that the RPM is quite low because the fan
> is too weak, and I might later switch to the power drill to improve that,
> but applying the liquid only after the motor is spinning is definitely very
> important.
>
> > You need to dispense liquid in middle of wafer as liquid will online move
>
> outwards.
>
> Obviously :)
>
> > I guess, you're experiencing problems because you didn't apply a primer
>
> first.
>
> I only did a test, spinning oil onto a coin. I guess that the primer helps
> with wetting and/or sticking to the wafer surface, which wasn't (yet) a
> problem in my test. Anyway, good to know!
>
> Greetings,
> Martin
>
>
> On Wed, Apr 28, 2021 at 5:06 PM David Lanzendörfer <
>
> leviathan@libresilicon.com> wrote:
> > Exactly.
> > First you've gotta spin up the wafer, and then you've gotta dispense it
> > kind of towards the center, but it's not so critical.
> > I guess, you're experiencing problems because you didn't apply a
> > primer first.
> >
> > https://www.3mdeutschland.de/3M/de_DE/unternehmen-de/produkte/~/3M-Silan-G
> > las-Primer-Transparent-1-L-Flasche/?N=5002385+3294237313&rt=rud
> >
> > Cheers
> > -lev
> >
> > On Wednesday, April 28, 2021 12:24:57 PM WEST Staf Verhaegen wrote:
> > > On wo, 2021-04-28 at 11:23 +0200, Martin Geisse wrote:
> > > > Hi,
> > > >
> > > > - spin coating
> > > >
> > > > I finally tried to build a makeshift spin coater the way Sam Zeloof
> > > > did, by mounting a plastic can on top of a CPU fan (actually a case
> > > > fan from another device I had lying around). I can't say this is the
> > > > way to go... the fan is way too weak to spin the can at a meaningful
> > > > speed. It is also very hard to center the can exactly, so it wobbles
> > > > a lot and that probably reduces the speed even more. Mounting a die
> > > > without a container would allow the fan to spin faster, but would
> > > > likely clog the fan with chemicals in no time. I'll next try my
> > > > original idea, to mount the can to an axle that I'll stick into a
> > > > power drill.
> > > >
> > > > One thing I did find out is that the coating liquid should be evenly
> > > > applied before spinning. It will NOT spread to the whole surface by
> > > > itself, but rather run to a single direction in a concentrated
> > > > stream, probably due to surface tension.
> > >
> > > If I remember correctly the spin coaters used in clean rooms first spin
> > > up the wafer and then dispense the liquid. You need to dispense liquid
> > > in middle of wafer as liquid will online move outwards.
> > >
> > > greets,
> > > Staf.
> >
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