coating / chemicals / litho / strategy
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. - chemicals I did find this resist which is meant for PCB etching, so I don't know yet whether it has some kind of "grain size" that limits the resolution. The datasheet explicitly states that it can take up to 40% hydrofluoric acid, though, and be used for glass etching (so I hope it will actually stick to glass). It is also liquid until soft-baking, so spin-coating should be possible. https://www.reichelt.de/fotopositiv-resist-positiv-20-200-ml-kontakt-235-p94... WRT hydrofluoric acid, there is something called "glass etching cream", the best-known brand being "Armour Etch". This contains fluorides, i.e. HF salts, is *somewhat* safer than HF itself (less fumes I think, but don't get it on your skin), and can be ordered by private individuals. The downside is that I could not find any information on whether it contains an abrasive. - photolithography Sam Zeloof used a modified DLP projector for his litho setup. He either used magic to do that or chose exactly the right projector. I took apart a used DLP and the UV filter is the only thing that could be taken out without destroying the projector. The color wheel, and even more so the optics, are buried under tons of other stuff, most of which is glued together. Also, the optics path itself is mostly glued. So I think David's plan of taking the DMD chip and building his own optics setup is a far better idea than modding a projector. To me as a layman in these things, stiching a larger image together from multiple images with a stepper sounds more logical than using multiple DMD chips. This XY table is cheap and has stepper motors that can position the table in increments of 5 microns. I have actually wondered if a first prototype should use a DMD at all, or just focus a single UV LED and "draw" by moving the XY table. https://www.amazon.de/Proxxon-27100-MICRO-Koordinatentisch-KT/dp/B000S81MHY - strategy I also thought a bit about who would be interested in making your own chips. High-volume production has far better, established processes, and low-volume production would use an FPGA or other off-the-shelf parts. Silicon testing before production isn't useful when the process is different. This leaves education and hobbyists. In other words, a free silicon process must be sustainable based solely on education and hobbyists, otherwise it won't stand a chance. There is another problem that goes in the same direction: a "democratized" chip making process should not rely on actors like INL, because there are too few of them -- less than 10 in the whole of Europe. Even if INL agrees to host the LibreSilicon process, a single decision by INL that chip making isn't interesting anymore can shut the whole thing down. I'm not particularly enthusiatic about the "glove box" idea either because I don't think it is practical, nor doable in a useful price range. The usual answer to the "expensive tools" problem is shared labs, usually as "fab labs", "makerspaces" or similar. I think this is a way in which chip making could actually work, especially if it works on dual-use tools that benefit a makerspace in other ways, like an XY table, microscope etc. I wanted to contact a local makerspace in my town, but unfortunately Germany just went into full Covid lockdown, so it's going to take a while until that. Greetings, Martin
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.
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-Gla... 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.
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-Gla...
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@list.libresilicon.com https://list.libresilicon.com/mailman/listinfo/libresilicon-developers
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.
_______________________________________________ Libresilicon-developers mailing list Libresilicon-developers@list.libresilicon.com https://list.libresilicon.com/mailman/listinfo/libresilicon-developers
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... 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.
_______________________________________________ Libresilicon-developers mailing list Libresilicon-developers@list.libresilicon.com https://list.libresilicon.com/mailman/listinfo/libresilicon-developers
Hi I think this one is more suitable: 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@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.
_______________________________________________ Libresilicon-developers mailing list Libresilicon-developers@list.libresilicon.com https://list.libresilicon.com/mailman/listinfo/libresilicon-developers
Hi, on a second thought, I'm no longer sure that the projector approach is even necessary to get some simple results. Real early chips were, IIRC, exposed through a mask made out of tape on some substrate (articles say vellum, but Wikipedia is ambiguous on what that even is, but I think any substrate will do as long as its flat and UV-transparent). AFAIK glass is UVA-transparent, so it will probably work as a substrate too, at least with that photoresist I found. Granted, that isn't maskless anymore, but a simple mask should be rather easy to make that way, it just doesn't scale well to complex masks. Scaling the mask down to die size is easy with the optics from the dismantled projector. As a test, I projected a miniature version of my cellphone screen onto the table. I'll next order some of the photoresist and do some exposure experiments, including masking with tape. Greetings, Martin On Fri, Apr 30, 2021 at 6:08 PM David Lanzendörfer < leviathan@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@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.
_______________________________________________ Libresilicon-developers mailing list Libresilicon-developers@list.libresilicon.com
https://list.libresilicon.com/mailman/listinfo/libresilicon-developers
Hi So my long term strategy is to use a DMD device and then increasingly making the feature sizes smaller and the pixel density higher, as soon as the mechanics has been figured out. In the long run, I might even be able to sell some of those steppers and have nice little side income from it, as well as providing patterning systems for hobbyists as well as the industry. Cheers -lev On Sunday, May 2, 2021 7:17:41 AM WEST Martin Geisse wrote:
Hi,
on a second thought, I'm no longer sure that the projector approach is even necessary to get some simple results. Real early chips were, IIRC, exposed through a mask made out of tape on some substrate (articles say vellum, but Wikipedia is ambiguous on what that even is, but I think any substrate will do as long as its flat and UV-transparent). AFAIK glass is UVA-transparent, so it will probably work as a substrate too, at least with that photoresist I found. Granted, that isn't maskless anymore, but a simple mask should be rather easy to make that way, it just doesn't scale well to complex masks.
Scaling the mask down to die size is easy with the optics from the dismantled projector. As a test, I projected a miniature version of my cellphone screen onto the table.
I'll next order some of the photoresist and do some exposure experiments, including masking with tape.
Greetings, Martin
On Fri, Apr 30, 2021 at 6:08 PM David Lanzendörfer <
leviathan@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@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.
_______________________________________________ Libresilicon-developers mailing list Libresilicon-developers@list.libresilicon.com
https://list.libresilicon.com/mailman/listinfo/libresilicon-developers
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@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@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.
_______________________________________________ Libresilicon-developers mailing list Libresilicon-developers@list.libresilicon.com
https://list.libresilicon.com/mailman/listinfo/libresilicon-developers
_______________________________________________ Libresilicon-developers mailing list Libresilicon-developers@list.libresilicon.com https://list.libresilicon.com/mailman/listinfo/libresilicon-developers
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@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@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.
_______________________________________________ Libresilicon-developers mailing list Libresilicon-developers@list.libresilicon.com
https://list.libresilicon.com/mailman/listinfo/libresilicon-developers
_______________________________________________ Libresilicon-developers mailing list Libresilicon-developers@list.libresilicon.com https://list.libresilicon.com/mailman/listinfo/libresilicon-developers
participants (4)
-
David Lanzendörfer -
Martin Geisse -
Staf Verhaegen -
Thomas Parry