
3D Printing Integrated Circuits: What's Possible Now and in the Future? - peter_d_sherman
https://www.nano-di.com/blog/2019-3d-printing-integrated-circuits-whats-possible-now-and-in-the-future
======
abdullahkhalids
While possibility of creating ICs in a "homelab" remains years or decades in
the future, it is an innovation that is very important to strive for. The
world of information has become increasingly dangerous, and trust is in short
supply. We need stronger guarantees that our computational hardware is secure
and backdoor-free and the best (but not perfect) way of doing it is to
manufacture it yourself.

Libre Silicon [1] is one organization that is striving forward and I am
hopeful they will make great progress.

Edit: when a high schooler can fabricate ICs in his garage [2], you know with
enough effort, a lot of progress can be made on the problem

[1] [https://libresilicon.com/](https://libresilicon.com/)

[2] [http://sam.zeloof.xyz/first-ic/](http://sam.zeloof.xyz/first-ic/)
[https://news.ycombinator.com/item?id=20657398](https://news.ycombinator.com/item?id=20657398)

~~~
UncleOxidant
The last news in the news section of the libresilicon site you linked was from
2018 - is it in active development still?

~~~
av3csr
There was a talk at CCC late last year where they talked about their std cell
library
[[https://m.youtube.com/watch?v=jA7BHuAo9u0](https://m.youtube.com/watch?v=jA7BHuAo9u0)]

------
sasaf5
> researchers at the Air Force Research Laboratory and American Semiconductor
> recently 3D printed microcontroller SoCs from polymers on a flexible silicon
> substrate.

Then in the source:

"we took silicon IC chips and thinned them until they became flexible but
retained their circuit functions."

So no, they did not 3D print an SoC from polymer.

Also, the chip manufacturing process is already, in a sense, additive (you
deposit layers of material on each other). Unless the author is proposing
printing billions of gates and wires one by one, I don't see where this is
going. And if that's the case, the cost structure would exceed the traditional
process many times, even if you are trying to make just a single chip.

~~~
alted
The best actually-printed-by-an-inkjet-printer circuits I know of are simple
ring oscillators of at most ten transistors or so (e.g., [1]---and they're
pretty bad transistors at that), and even the simplest microcontrollers
require thousands of transistors.

The paper [2] is a good review of the difficulties. Inkjet printing has at
best a ≈20um minimum feature size (vs. 0.01um current transistor sizes), and
the material choice is really hard: instead of silicon, you need to make
semiconducting inks using funky organic molecules like
6,13‐bis(triisopropylsilylethynyl) pentacene (TIPS‐pentacene). [3] is a good
recent paper trying to work around some of these limitations. So everything is
still very much in the research phase.

Although inkjet printed circuits won't be anywhere near current silicon
circuitry anytime soon if ever (and inkjetting transistors is the best (and
kinda the only) method of 3D printing circuits we currently have), the
different form factor may be useful. Circuits---even if only a few thousand
transistors---could be printed on 3D geometry for interesting microfluidics
capabilities, flexible circuits might make good healthcare sensors, and [4] is
even studying flexible spacecraft via printed electronics for surprisingly
economical space debris removal. And combining all this with 3D printed
mechanical parts (via, e.g., the impressive PolyJet [5], which is basically
inkjetting layers and lacks only the right materials to print electronics)
will be fun.

(as to the source's Air Force Research Lab printed chips, yeah, I can't find
further info, either, and agree it was probably sandpapering away most of the
spare silicon bulk of an integrated circuit [impressive, useful, but not
printing])

[1]
[https://doi.org/10.1021/acsnano.6b06041](https://doi.org/10.1021/acsnano.6b06041)
[2]
[https://doi.org/10.1002/admt.201700063](https://doi.org/10.1002/admt.201700063)
[3]
[https://doi.org/10.1038/s41598-017-01391-2](https://doi.org/10.1038/s41598-017-01391-2)
[4] [https://www.nasa.gov/feature/brane-
craft/](https://www.nasa.gov/feature/brane-craft/) [5]
[https://www.stratasys.com/polyjet-
technology](https://www.stratasys.com/polyjet-technology)

------
girishso
I mis-read the title, thought it’s about 3D printing the PCBs. That’s
something easily achievable and useful to hobbyists like myself.

~~~
marcosdumay
That's relatively easily achievable, a stepping stone on the path to ICs, and
serves a large market that already exists.

Yet, I think there are no commercial offers, and no companies focused on
building it (differently from ICs). Go figure.

~~~
joshvm
This does somewhat exist for commercial 3D printed PCBs (not ICs) :
[https://www.lpkf.com/en/industries-
technologies/electronics-...](https://www.lpkf.com/en/industries-
technologies/electronics-manufacturing/3d-mids-with-laser-direct-structuring-
lds)

LPKF sell a funky machine which will deposit 3D traces onto a printed part. We
have one of these in a lab at our uni, along with a lot of other expensive
LPKF kit, but it's so specialised that I doubt anyone ever uses it. They have
lots of interesting demo parts made with it, the obvious use case is antennas
that are embedded in the enclosure.

~~~
marcosdumay
I was thinking more on the line of cheap one-off PCBs that you send from your
computer and take from the machine in an hour or two, like what hobbyists are
doing.

This one is so much cooler but more expensive too. I hope they find some large
market to grow into.

~~~
joshvm
Yeah LPKF's stuff is very high end. I'm 99% sure the only reason we have any
of their machines is that someone had a massive budget to blow with a tight
deadline. Or they had no idea what they were buying and got sweet talked by a
rep. Or they _absolutely_ knew what they were buying and someone high up just
signed off on it. We also have stuff like Metal 3D printers which are six-
figures, so why not? The problem with using is that it's so expensive, so
nobody is allowed to use it without training. Everyone else just submits jobs
to the mech workshop and they'll etch it for you.

But.. when you think that a one-day turnaround on a small run of PCBs can cost
easily $500+ if you need weird requirements, these sorts of machine can start
to save money. They can do tolerances below most of the cheap fab houses (like
BGA fanout, RF parts, etc). PCBTrain will charge you £400 for a 2-day
turnaround on a 50x50mm 2 layer board!

At home I don't know why you'd want to 3D print a circuit versus milling or
laser exposing it. You can get cheap mills with decent tolerances these days
[1]. Of course LPKF also sell these sorts of machines with absurd tolerances
and high prices!

In theory you can use conductive filament and a multi-material printer. One
use case for that is actually making custom RF shields. Otherwise the only 3D
printed circuits I've seen are kind of cheating - either using the printer to
make the etch mask, or by printing channels which you can fill with conductive
paint or epoxy (those are nice though).

[1] [https://wegstr.com/CNC-Wegstr-(English)](https://wegstr.com/CNC-
Wegstr-\(English\))

~~~
marcosdumay
> At home I don't know why you'd want to 3D print a circuit versus milling or
> laser exposing it.

I have absolutely no requirement on an additive process. I also don't think
"home" will net enough of a market, it's more for "design house". What I think
is missing is some box you can buy where you just add the material, send the
design from a computer and an hour later you have a usable PCB.

CNC mills do kinda solve the problem, on its most basic form. But it is very
common that one would need at least two layers, and it would be a huge add-on
if it could apply masks and silk. The mills are also not that well packaged
for the job - it would make a lot of difference if it would just be enclosed.

But anyway, that's in no way a rant about the market or anything like that.
It's just that it's unsettling to see somebody jump all the way into ICs when
solving the same problem on an easier level is already a useful product.

------
Animats
Electron beam lithography for direct writing ICs has been around for decades.
Put down a layer of resist, expose with a steered electron beam. It works
fine, down to at least 7nm, but it's slow. It's never been cost effective for
making ICs, except for occasional one-offs. It's mostly used to make masks.

~~~
alted
Sure. Heidelberg's recently made [1] some cool tools ("maskless aligners")
that can expose a ≈150mm wafer in an hour or so down to ≈500nm resolution,
which is very convenient when rapidly iterating through one-off low-resolution
designs or something in a research lab (for comparison, electron beam
lithography does the same to ≈10nm resolution in maybe a day). It's still part
of the whole fabricate-everything-as-2D-layers-on-a-wafer paradigm, though,
and has the same limitations (e.g., temperature limits) as standard silicon
circuitry made with conventional photolithography.

[1] [https://heidelberg-instruments.com/en/#products](https://heidelberg-
instruments.com/en/#products)

------
blueblisters
> To increase the printing resolution, the additive manufacturing industry may
> need to devise a completely new printing process. Currently, inkjet 3D
> printing provides among the highest resolution features for 3D printing
> PCBs, but it remains to be seen if this process can be improved to provide
> resolution less than 1 micron.The future of 3D printing integrated circuits
> will likely adapt a photolithography process or functional self-assembly
> process to produce integrated circuits with competitive resolution.

I thought the whole appeal of 3D printing is tool-less manufacturing.
Photolithography typically involves using photomasks, which is not exactly
suitable for prototyping or low-volume production.

~~~
akiselev
There's been lots of progress on DIY/academic maskless photolithography by
using TI digital micromirror devices from projectors to reflect light into a
microscope for exposing photoresist. They even sell a UV version that is just
for this purpose (maskless light manipulation in general). As usual, the
bigger issue is alignment between steps and the etchants.

Still don't know what it has to do with 3d printing, except the article sounds
like GPT3 mindlessly connecting lithographic resin 3d printers and
semiconductor photolithography, with a Google Scholar search on those terms as
a data set.

~~~
blueblisters
> maskless photolithography by using TI digital micromirror devices from
> projectors to reflect light into a microscope

I just looked this up. It's incredible that maskless photolithography is even
possible. Are these devices used in any high volume processes for
manufacturing PCBs, for example?

~~~
brennanpeterson
The more common maskless route is laser direct write. That is capable to
micron level dimensions, and multicolor variants have been proposed to allow
submicron.

Ebeam direct write is capable to NM level features. Just slow.

[http://www.periodicstructures.com/](http://www.periodicstructures.com/)

Has some neat papers on this.

------
nipponese
Why does this post keep getting re-submitted?

~~~
nrp
I was curious too, and it turns out that Nano Dimension is publicly traded,
has seen its market cap collapse over the last four years, and oddly seen a
massive spike in trading volume over the last four months. I suspect this is
another Microvision-like scenario where a stock on the verge of dropping into
the pink sheets is getting gamed by people trying to convince others that it
is the next big thing.

------
Junk_Collector
3D printing is hype but beyond a broad assertion that it would be cheaper for
high performance LRIP devices I don't feel like a case for it being better
than current manufacturing techniques is made in the article. They also
completely neglect the fact that you can 3D print complex sub micron
structures today using a FIB (a common semiconductor tool) and the technology
to do so has existed for over 30 years. It hasn't taken over yet for a reason.

~~~
alted
Both FIB deposition and its cousin Focused Electron Beam-Induced Deposition
(FEBID) are pretty nifty; they can cut/add materials down to maybe 1nm (!)
resolution. However, they're extremely slow: they can only affect a single
spot at a time and move at maybe only 100nm/s movement, so patterning a useful
circuit may take days; it's mostly useful for research work. I don't think
I've seen anyone figure out the chemistry to use it to print doped
semiconductors, so transistors might not be doable anyway.

Really the only other sub-micrometer 3D printing category right now is two-
photon lithography (shine a laser to cure a liquid resin into a solid, like
common resin 3D printing), which can generally only use a single, even-more-
specialized-than-required-for-inkjet material---almost always an insulating
polymer---for an entire structure.

------
lvs
This article is really too lightweight. It's not as much a review of current
research as it is something that would fill whitespace in an industry mag.

------
bsder
As always, the problem in VLSI isn't technology--it's _tools_.

Places like X-Fab can run a mask set for you at around $50K. Tools will run
you $150K+.

Side note: X-Fab, fix your !@#$ing site already. You got hacked on July 5th.
Still being unable to log in a month later doesn't bespeak competence.

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tmaly
I know its a bit off in the future, but imagine the possibilities of doing
this from your garage. We could see all sorts of innovation.

------
soyrunner
Back in the 1970's Page Burr at Photocircuits developed Multiwire.

