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

Sun May 2 13:40:10 CEST 2021

Hey Thomas
This is BRILLIANT! I'll go through the electronics now and we'll discuss it in 
our weekly Mumble session at 6pm UTC (Important, the time is UTC!), so in
case you wanna talk about the electronics, feel free drop by on 
murmur.libresilicon.com then.
This immensely cuts down the R&D time, because "all" we've got left to do
now is to figure out the stepper mechanics.

Cheers
-lev

On Sunday, May 2, 2021 12:18:48 PM WEST Thomas Parry wrote:
> 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=T3oQ
> > rply3y%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=BZ
> > Be> 
> > > 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.
> > > > > > 
> > > > > > _______________________________________________
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> > > > > > Libresilicon-developers at list.libresilicon.com
> > 
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> > 
> > 
> > 
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