[Libre-silicon-devel] coating / chemicals / litho / strategy

Sun May 2 13:18:48 CEST 2021

Hi,

I went down this path about a year ago and created a prototype board for
the DMD chip. I don't really have the bandwidth to take it further at the
moment, but I've just uploaded the design files, maybe it's useful for the
LibreSilicon efforts.

https://github.com/yrrapt/icfab

Cheers,
Thomas

On Fri, 30 Apr 2021 at 18:08, David Lanzendörfer <leviathan at libresilicon.com>
wrote:

> Hi
> I think this one is more suitable:
> https://eu.mouser.com/ProductDetail/Texas-Instruments/DLP2000AFQC?
> qs=T3oQrply3y%252B2%252BSUG%252B1A5CA%3D%3D
> <https://eu.mouser.com/ProductDetail/Texas-Instruments/DLP2000AFQC?qs=T3oQrply3y%252B2%252BSUG%252B1A5CA%3D%3D>
>
> The board is connected through an FQC 42 connector socket, which I'm
> right now unable to find online.
> I guess I've gotta do some more digging on Alibaba and so on, in order
> to get my hands on one of those.
>
> Cheers
> -lev
>
> On Friday, April 30, 2021 3:34:10 PM WEST Martin Geisse wrote:
> > 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=BZBe
> > i1rCqCAQetmBz0G1xQ==
> >
> > 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 at 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 at 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.
> > > > >
> > > > > _______________________________________________
> > > > > Libresilicon-developers mailing list
> > > > > Libresilicon-developers at list.libresilicon.com
> > > > >
> https://list.libresilicon.com/mailman/listinfo/libresilicon-developers
>
>
>
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