
Home Chip Fab - JabavuAdams
http://sam.zeloof.xyz/category/semiconductor/
======
spectramax
I was at Semicon Japan last year in December and I learn about the coolest
semiconductor company (non profit research organization) ever - MinimalFab
[1]. There isn't much information their website but this [2] video explains
what MinimalFab is about. Essentially, it is a cleanroom-free, modularized fab
where each process step in a fab is like a little ATM machine. Miniaturization
of complex fab processes is mind blowing and everything is contained inside
the machine including a Class 100 environment. Load a tiny quarter sized wafer
in a cassette to process and move material from one machine to another. This
kind of a fab setup would be incredibly useful to R&D fabs in universities and
small scale fabrication for military, space, defense and perhaps even hobby
use.

[1] [https://www.minimalfab.com/en/](https://www.minimalfab.com/en/) [2]
[https://www.youtube.com/watch?v=WsOVbmfYxoM](https://www.youtube.com/watch?v=WsOVbmfYxoM)

~~~
LargoLasskhyfv
That is _very_ interesting! I watched that and found some more information
after searching a little:

[1] [https://www.yokogawa.com/yjp/solutions/solutions/minimal-
fab...](https://www.yokogawa.com/yjp/solutions/solutions/minimal-fab/)

It seems like this fab is a demonstrator, and is planned for sale. This makes
me wonder if/when this will be available for maker style setups, at which
process nodes & price per piece. Would be nice to be able to design some fully
custom ip, have it tested, bonded and packaged, and optionally soldered, like
you can have it with pcb services today.

One can dream, yes?

~~~
LargoLasskhyfv
Found another, more technical video, but couldn't recognize anything about
process node/feature size. Anyways, here it is:

[1]
[https://www.youtube.com/watch?v=hViCDab0E2A](https://www.youtube.com/watch?v=hViCDab0E2A)

~~~
LargoLasskhyfv
Nikkei Article from December 2016 mentioning 0.8 micron, while aiming for 0.35
micron in 2018. So that's it, i guess?

[1] [https://asia.nikkei.com/Business/Biotechnology/Minimal-
fab-t...](https://asia.nikkei.com/Business/Biotechnology/Minimal-fab-tech-
promises-faster-cheaper-chip-production)

According to wikipedia the following CPUs were built with that:

[2]
[https://en.wikipedia.org/wiki/350_nanometer](https://en.wikipedia.org/wiki/350_nanometer)

Which i think of as more than sufficient to finally being able to implement
something like SCED, WAM, CHERI, Applecore, whatever in whichever way one is
able to wrap his brains around it. Asynchronous, fully static?

[https://en.wikipedia.org/wiki/Mead_%26_Conway_revolution](https://en.wikipedia.org/wiki/Mead_%26_Conway_revolution)
(with MEMS(for sensing)) from scratch?

 _I want it all! I want it NOW!_

~~~
hollerith
That's cool, but your [1] seems to say that the machine uses a wafer 12.5 mm
in diameter, which is is probably less area than any of the CPUs in your [2].

~~~
LargoLasskhyfv
Should suffice for my needs, see for example here

[1] [https://en.wikipedia.org/wiki/R4200](https://en.wikipedia.org/wiki/R4200)

under R4300i which mentions 45mm² for the die.

Also mentioned here [2] [https://bits-chips.nl/artikel/small-series-of-chips-
profitab...](https://bits-chips.nl/artikel/small-series-of-chips-profitable-
by-flexible-concept-minimal-fab/)

are 0.25-micron to be released this year, with 190nm and smaller on the
roadmap.

Which leads us to [3]
[https://en.wikipedia.org/wiki/250_nanometer](https://en.wikipedia.org/wiki/250_nanometer)
at least.

Maybe not comparable in die size for all the chips mentioned there, i don't
care so much, because i don't want to clone or emulate them. I want to go
simpler. Rebranch from the 70ies so to speak, to take all the roads not taken
since then. Just to see what's there :-)

------
hammock
Please don't dump your solvent down the drain like every Silicon Valley fab
did back in the day, poisoning the entire region for decades to come. Just
look up how many EPA Superfund sites are in the South Bay due to
trichloroethylene, TCE contamination. Dispose of it properly and safely.

~~~
SkyPuncher
> Dispose of it properly and safely.

I see a lot of people say this, but I rarely see any actionable advice.

How does your average residential person find and dispose of chemicals like
this? Seems like most people end up pouring them down the drain simply because
they don't know how to actually find a better means of disposing them.

~~~
henryfjordan
A person doesn't get a pass on things like this because other people didn't
spoon-feed them the info. Read the law, call the EPA, google it.

Ultimately if you want to use chemicals that have the potential to poison our
shared environment you need to be willing to do the legwork to be confident
that you are doing things responsibly.

~~~
j88439h84
We don't give people cars without a test. Perhaps such chemicals shouldn't be
dispensed without training.

------
KenoFischer
I love this! Nanofabrication was one of my favorite classes and even with
fancy equipment and worked out ahead of time instructions making a transistor
took a huge amount of time and a good number of missteps. Can't imagine the
amount of work required to do it all from scratch. Though I also think the
safety lectures scared me sufficiently that I wouldn't want to touch HF acid
ever again.

~~~
adamnemecek
What class is this?

~~~
KenoFischer
The course number was ES277, though the professor left and it doesn't look
like it's currently being offered under that course number. Not sure if
there's a replacement class or the department decided to quietly shut it down.
Wouldn't be surprised if it was the latter. The class was rumored to be the
second most expensive one offered by the university, after the one where you
got to grow organs in a petri dish. I also tried taking that one, but
apparently not being a biologist was disqualifying.

~~~
adamnemecek
Lol what's the name of the biology class?

------
bcaa7f3a8bbc
And remember that the author Sam Zeloof was still studying in highschool when
he completed this project.

~~~
DC-3
He must have tolerant parents to allow experiments involving baths of HF and
Piranha solution in their garage!

Seriously impressive though.

~~~
amelius
Or ignorant parents.

~~~
dymk
A highschooler don't end up with a garage full of equipment like that unless
their parents are already in the industry.

~~~
faissaloo
Nope, Zeloof got most of the stuff on Craigslist and Ebay. The big stuff is
usually pretty old, and alot is hacked together (e-beam stepper) or custom
built entirely (sputtering chamber, or whatever the plasma machine is called I
forget).

~~~
bcaa7f3a8bbc
He also purchased a decommissioned, broken electron microscope from a
university lab on eBay, and repaired it by himself.

~~~
kokey
That answered one of the biggest questions I had when I saw that CRT display
magnification of the chip. Well done to him, hope he doesn't get bored in
college though I'm sure he'll find ways to pass the time.

------
sokoloff
Chris G interviewed Sam on the AmpHour Podcast #390; it was a good listen if
you're interested in the topic.

[https://theamphour.com/390-an-interview-with-sam-
zeloof/](https://theamphour.com/390-an-interview-with-sam-zeloof/)

------
rwmj
This is a BBC documentary about Intel's fab from the late 1970s. It's similar
technology level. Also probably the first and last time that Intel allowed
cameras into one of their fabs:

[https://www.youtube.com/watch?v=HW5Fvk8FNOQ](https://www.youtube.com/watch?v=HW5Fvk8FNOQ)

BBC Horizon: 1977-1978 Now The Chips Are Down

------
otakucode
What happens to old fab tech? A few years ago I tried searching around online
to see if there was anywhere you could buy decommissioned machinery for
fabricating NAND flash, but I couldn't find anything or any sign that such
things ever really come up for sale. Has anyone worked in a fab or otherwise
have some idea of what happens to the stuff that worked at larger process
sizes?

~~~
deepnotderp
A lot of the stuff, e.g. 193i immersion litho, gets reused the by the fabs,
other stuff gets used for older nodes, which are often still thriving, e.g.
180nm is popping for analog.

~~~
makomk
Also, some of it just gets trashed. I remember seeing photos of a bunch of
equipment just sitting away rusting slowly in a parking lot somewhere in (I
think) the UK. Obsolete node and wafer size, no real market for it.

------
Avery3R
Website seems like it got the HN hug of death, archive:
[https://web.archive.org/web/20190809200012/http://sam.zeloof...](https://web.archive.org/web/20190809200012/http://sam.zeloof.xyz/category/semiconductor/)

------
phkahler
Is this kind of thing possible with less toxic chemistry?

~~~
esmi
No. When this article was previously posted there was an interesting thread on
this topic.

[https://news.ycombinator.com/item?id=16955549](https://news.ycombinator.com/item?id=16955549)

Edit: I should mention that one can make a rectifier using household
chemicals. Caution is still warranted of course.

[http://www.hpfriedrichs.com/radioroom/cu-diode/rr-cu-
diode.h...](http://www.hpfriedrichs.com/radioroom/cu-diode/rr-cu-diode.htm)

------
parsimo2010
This is really cool. Jeri Ellsworth made some videos several years ago about
homemade silicon transistors, but it was impractical due to the low precision
and large size. Getting down to 5 um is a few orders of magnitude worse than a
top end chip foundry today, but it's at least useful and you can fit all of
the necessary equipment into a spare bedroom.

------
bogomipz
This is really fascinating. I apologize if this is a silly question but under
the Fabrication section there is a pic titled "physical structure(Texas
Instruments, 1997.)" My question is why do all of the components always look
so "puffy" or "fuzzy" in these chip zoom-in pics? I guess I'm always surprised
that such a precision process produces something with such imperfect looking
shapes. Or are these slightly amorphous shapes just a distortion produced by a
scanning electron microscope?

EDIT: This is the pic I was asking about: [http://sam.zeloof.xyz/wp-
content/uploads/2018/04/na_1.png](http://sam.zeloof.xyz/wp-
content/uploads/2018/04/na_1.png)

~~~
Kirby64
You're referring to the fact that the edges aren't really sharp and are kind
of 'soft', right? Like, everything isn't 90 degree angles and is kinda rippley
in places?

If so, that's not an SEM issue, that's just what it looks like. Photo exposure
by it's very nature doesn't edge things 100% properly, diffraction or tiny
misalignments causes stuff to end up being 'soft'.

Also, keep in mind that was from 1997. Fab tech has gotten way better;
although we don't have a scale reference, I imagine if you were to make the
same device on modern tech everything would look a lot 'sharper'. You still
can't get away from some softness though.

~~~
bogomipz
>"You're referring to the fact that the edges aren't really sharp and are kind
of 'soft', right? Like, everything isn't 90 degree angles and is kinda rippley
in places?"

Yes to both of these questions. "Soft" is probably a better way to articulate
this, thanks. I'm not following the explanation of this being caused by
photography however. Is this specific to photography at this scale?

>"I imagine if you were to make the same device on modern tech everything
would look a lot 'sharper."

I don't have an example handy however I have seen more recent micrographs and
they display the same "softness" and lack of true 90 degree angles etc.

~~~
Kirby64
By photography, I meant the photolithography, as you mentioned to another
replier. This inherently will cause softness as described since there's always
going to be light leakage and the masks you use will never be truly perfect.
Given the sizes though, they're pretty damn good.

As for 'modern tech' vs. old tech, I'm referring to if you made the same size
silicon structure on newer tech. When you get down to 7nm or whatever, the
same problems show up (or even new ones) because the sizes get smaller. I
wouldn't be surprised if the image from 1997 is 180nm or larger nodes.

Also, unlike the other replier, I don't think there's any meaningful
diffraction (causing softness) by the actual SEM images... they don't use
glass lenses like traditional cameras.

~~~
bogomipz
Thanks for the clarification. Agreed, given the scale of these they're pretty
damn good :) Cheers.

------
bobcostas55
Once space exploration really gets going, mobile chip fabrication is gonna be
a pretty big deal.

~~~
mLuby
NASA had a 1980 study° of space fabrication systems where they referred to
small, light, hard-to-manufacture parts as "vitamins." These vitamins (ICs
certainly, perhaps special sensors or high-quality optics) would likely be the
_last_ part of the manufacturing system to be moved from Earth into space due
to the complexity (=mass/volume) of fabrication and relative ease of
transportation.

°[http://www.islandone.org/MMSG/aasm/AASMIndex.html](http://www.islandone.org/MMSG/aasm/AASMIndex.html)

~~~
lkschubert8
This terminology also got carried on top the self replicating 3d printer
world. Any part that cant be produced by a printer is a vitamin.

------
koskaj
This guy makes me think of Kvothe in the Arcanum building sympathy lamps.

------
weinzierl
I find article about DIY chips super exciting. Given how important and
ubiquitous chips are I think every university and maybe even schools should
have a mini fab to teach the public how sand turns into a computer.

I was lucky to have this at my university. We had a professor who build a
complete mini fab, mostly from industry donations of discarded equipment. Our
semester built a complete and functioning surface acoustic wave (SAW) filter
from the wafer to the bonded and housed chip. One of the best practical
courses I've ever had.

------
CodiePetersen
Wow, very cool. I've been wanting to get into hardware for a while now. Well
just as long as I have been in programming to be honest which is about 10
years or so now. So as the useful things I can learn start petering off in
programming for me I think I will be diving into hardware as a hobby. I have
been doing some robot stuff with me niece, but not as much as I would like.
But this article and spectramax's comment I think has kind of warmed that
little ember of curiosity in it again.

Thanks.

------
dang
Thread from 2018:
[https://news.ycombinator.com/item?id=16955549](https://news.ycombinator.com/item?id=16955549)

------
bobjordan
Super impressive and don't miss his youtube. The first video I saw he's
setting up his circa 1996 scanning electron microscope, which he bought from
eBay. I thought my optical CMM was cool but now I'm envious. Time to do some
dumpster diving in Shenzhen.
[https://youtu.be/RJXio_jpc_Y](https://youtu.be/RJXio_jpc_Y)

------
gen3
This is awesome! It looks like he did most of this before going to college,
amazing!

------
Taniwha
I bet there's some overlap with thee the $300 UV resin printer technology that
has just become available - they print at 50micron - essentially they're just
a TFT cell phone screen with a UV backlight.

------
craigr1972
Another story that highlights why I absolutely love HN..

------
eternauta3k
Now that MOSIS won't work with universities outside the US, this might be an
interesting way to have very simple student designs fabricated.

------
cr0sh
This is all very interesting and amazing, and kudos to the person for being
able to do this - but I think we need to take a step back here a bit; this
doesn't look like something that "just anybody" could replicate.

For one, this person seems to have some very advanced knowledge of some very
advanced processes - I am not even sure where one would gain such knowledge
from easily, though they do seem to have access to MIT in some manner.
Regardless of how it was gained, this knowledge of some of the very basic
processes and advanced tools involved would be foundational to this entire
enterprise (and it seems this person went to the trouble to build up to this -
but what foundation of knowledge they had prior to that point seem unknown?).

Secondly, they appear to have something more than just a simple "2-car garage"
\- unless the camera perspective is really skewed. The building they are in
looks to be like a large steel fabricated unit, 40'x 20'x 12' \- my numbers
might be off but it doesn't look like a simple garage or workshop, but rather
something you'd either pay a lot of money for to have erected on your (likely
sizeable) property, or its space at a leased business/industrial complex.

Third, from what I gather, much of their equipment is resold industrial
surplus off ebay (and probably other places); I know of one company, local to
me (Phoenix), which sells online via ebay such equipment (Equipment Exchange)
- assuming they are still in business. While what they sold was inexpensive -
even at "pennies on the dollar" you are not talking small amounts of money,
because some of that equipment is anything but inexpensive brand-new. I'm sure
there are other vendors as well for this kind of equipment, and if you know
what you want and need, you can probably strike some good bargains, but I
still can't imagine this being budget friendly for most people.

This all adds up to what seems to be a "hobby" that would require both extreme
dedication (time, energy, and knowledge acquisition) and considerable monetary
resources to implement. Not something that just anyone can do - it's not a
"maker friendly" endeavour. Maybe it can be miniaturized and simplified now
that it's been "proven" to be possible, which is a great thing in itself
(after all, it was more or less done with 3D printing and home CNC). Though I
am not sure how far that can be taken - then again, people have fabricated
some quite complex stuff before...

So all in all - this is amazing work, and does show the possibility. But
temper that with the reality of the situation: This person has some very
specialized knowledge gathered over who knows what kind of timeframe, and the
resources to purchase and bring together all of these tools and parts to do
this kind of thing. Even with all that, they still had and have a bunch of
trial and error. I'm amazed it could be done at all in a nominally "DIY"
manner. Congratulations to that!

~~~
furi
You're overhyping the knowledge a bit. It can't have been gathered over that
great a span of time because he was only in his late teens when he did this.
Also I've been able to work out most of it myself over a period of about a
year using the book "Introduction to Semiconductor Manufacturing Technology"
by Hong Xiao for general process layout (what steps are necessary, in what
order, with what chemicals, etc.) and a scattering of papers, chemical
datasheets and ResearchGate discussions for the specific parameters to use.

If anybody would like to get into this kind of thing I highly recommend that
book, it's very approachable for somebody coming from computing without a
particular semiconductor/chemistry/material science background.

~~~
ChickeNES
Do you have a list of the papers you found helpful in addition to the book?

~~~
furi
These were useful for parameters (conceptually anyway, I haven't done any hard
labwork with this yet):

Kirt R. Williams, Kishan Gupta, Matthew Wasilik - Etch Rates for
Micromachining Processing—Part II

Mark R. Jackson - Effects of Radio Frequency Power and Sulfur Hexafluoride
Flowrate on Etch Rate of Silicon Dioxide

S. A. Moshkalyov, C. Reyes-Betanzo, R.C. Teixeira, I. Doi, M.B. Zakia, J.A.
Diniz, J. Swart - Etching of Polycrystalline Silicon in SF6 Containing Plasmas

I.J. Kima, H.K. Moona, J.H. Leea, N.E. Leea, J.W. Jungc, S.H. Cho - Silicon
nitride etch characteristics in SF6/O2 and C3F6O/O2 plasmas and evaluation of
their global warming effects

[http://microchem.com/pdf/PMMA_Data_Sheet.pdf](http://microchem.com/pdf/PMMA_Data_Sheet.pdf)

These for further general process design/example values:

[http://ww2.che.ufl.edu/unit-ops-
lab/experiments/semiconducto...](http://ww2.che.ufl.edu/unit-ops-
lab/experiments/semiconductors/semiconductors-index.htm)

These are by no means the be all and end all, they were just useful for the
parts of the process I've looked at in detail so far and there are often
several options at every step for chemicals and approaches, these were suited
to what I was aiming for.

------
droithomme
Holy cow this is exceptionally impressive and amazing.

------
foobarbecue
404 :-(

~~~
foobarbecue
Woah, apparently this is because my workplace has added this website to the
super-block-without-even-telling-you list...

~~~
irq
I bet it's the .xyz tld that your workplace is blocking, but I don't know for
sure of course.

------
samrosea
I knew this guy's brother lol.

