24 ms·

Home Chip Fab

566 points by JabavuAdams 7y ago

gen3 7y ago
This is awesome! It looks like he did most of this before going to college, amazing!
bogomipz 7y ago
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 7y ago
  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 7y ago
    >"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.
    - marcosdumay 7y ago
      > Is this specific to photography at this scale? Yes. A smaller scale makes it worse, a larger scale makes it better. If you reduce things enough, everything will become so blurred that you won't be able to see anything (that's why we can't photograph atoms using visible light), and if you make things large enough your camera will become the bottleneck so a very small amount of blur is added to any object, whatever the size.
      - bogomipz 7y ago
        Ah I see, when you say "photo" you are referring to the photolithography used in the chip making and not the captured photo of the finished chip is that correct?
        marcosdumay 7y ago
        I mean the captured photography of the chip. Most of the time it is not done with ultraviolet light or electron microscopes, just with normal visible light cameras ans some very good lenses.
    - Kirby64 7y ago
      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 7y ago
        Thanks for the clarification. Agreed, given the scale of these they're pretty damn good :) Cheers.
  - deleted 7y ago
    [deleted]
- PhaseLockk 7y ago
  I can't see the image you're referring to at the moment, but I imagine the fuzziness you are seeing is due to this fact: chips perform better if the features are smaller. Because of this, manufacturers want to make chip features as small as they can without causing failures, which means that you are manufacturing things at the scale that your manufacturing precision is barely sufficient, which means that the components look ugly, but they (mostly) work.
  - fengazer 7y ago
    This. Every step in fabrication has limits on its resolution beyond the resolution of the machine exposing the polymer resist. The resist has a finite thickness (often comparable to the size of the feature you are trying to make). The developer solution works downwards through the exposed resist, but also outwards at the edges (where you will have some proximity effect in the exposure). Deposited metal or insulator sometimes sticks to both the bottom of the pit and the top of the resist without a clean break, or contains chunks or grains that make the coating uneven. Wet chemical etchants don't etch straight down, and often create rounded corners in cross-section. Every aspect of this has decades of optimization behind it, and its success in any one fabrication run is vulnerable to a frustrating number of variables. If there's an SEM cross-section of a device in a paper, it's likely because fabricating it was an accomplishment, and/or the design is in some way new (not ruling out other reasons of course: there's also "we have an SEM and not a lot else to put in the paper"). TL;DR: I agree. These things are very small and if we could make the corners sharper, that would remove one major barrier to making them even smaller. And then they wouldn't look so tidy anymore.
    - bogomipz 7y ago
      >"This. Every step in fabrication has limits on its resolution beyond the resolution of the machine exposing the polymer resist." I didn't quite understand what you meant here. Could you elaborate on this? What are some of those limits? >"These things are very small and if we could make the corners sharper, that would remove one major barrier to making them even smaller. And then they wouldn't look so tidy anymore." Aren't these contradictory? Did you mean to say "And then they would look so tidy"?
- pjc50 7y ago
  Necessarily it is operating at the limit of precision. If it wasn't blurry, you'd keep making it smaller until the blurring starts to become a problem again.
  - fengazer 7y ago
    This sums it up best.
- Junk_Collector 7y ago
  As mentioned in other posts, the process of making these types of devices tend to produce rounded structures. This is a byproduct of using Ion beams, deposition, lithography, etc in manufacture. BUT, the image is also made worse by how the image is captured. The picture you are looking at is a FIB (Focused Ion Beam) cut cross-section of a transistor which is then imaged by a SEM (scanning electron microscope). Probably in one of their fancy dual source beam devices. Depending on how you cut with the FIB, you can also push material downwards into lower layers and create a waterfall effect that will blur edges. It's can be very noticeable in rookie cuts but doesn't look like a major impact here. Imaging with the SEM itself can also cause distortion and blurring as trapped charge accumulates on the surface and deflects the electron beam slightly. You can see this where the edges get increasingly bright because charges gather and become trapped at the boundary of the conductive and insulating layers. The image isn't sharp enough for me to tell if that is poly-silicon or aluminum contact traces.
  - bogomipz 7y ago
    >"As mentioned in other posts, the process of making these types of devices tend to produce rounded structures. This is a byproduct of using Ion beams, deposition, lithography, etc in manufacture." Thanks for the detailed response. Might you have a link to one of those other posts or some other resources that talks about how these processes tend to produce rounded structures?
    - Junk_Collector 7y ago
      In the manufacturing process you have several methods that are used each with their own issues. Photo-lithography suffers from diffraction at the edges of features. Chemical processes undercut, overcut, and generally move around. They eat away faster at edges because of surface space and eat along different crystal lattice vectors at different rates. Plasma processes are effectively a hose of charged particles and have a sort of Gaussian distribution vs location of particle impact depending on your focus. And during the whole process, diffusion is trying to move everything around to boot. These effects exist at all scales, but when you get to IC scales, the effects can be dominant.
foobarbecue 7y ago
404 :-(
- foobarbecue 7y ago
  Woah, apparently this is because my workplace has added this website to the super-block-without-even-telling-you list...
  - irq 7y ago
    I bet it's the .xyz tld that your workplace is blocking, but I don't know for sure of course.
  - unethical_ban 7y ago
    I wish our infosec department would just trust the vendor reputation service and realize that gTLDs have been around for years now.
- haspoken 7y ago
  https://archive.is/http://sam.zeloof.xyz/category/semiconductor/ https://archive.is/http://sam.zeloof.xyz/category/semiconduc...
spectramax 7y ago
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
- dbcurtis 7y ago
  That looks very exciting for some research environments, and for some prototyping. But a 12mm wafer is certainly going to limit what you can do, and they make no mention of feature size. In the end, what you can accomplish is determined by the process and how easily your design tools let you target the process. I am sure there is a lot of academic research that could benefit greatly. As to prototyping, I have concerns that it would be difficult to do a part on this process and transfer it to a different process for scale.
- LargoLasskhyfv 7y ago
  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 7y ago
Avery3R 7y ago
Website seems like it got the HN hug of death, archive: https://web.archive.org/web/20190809200012/http://sam.zeloof.xyz/category/semiconductor/ https://web.archive.org/web/20190809200012/http://sam.zeloof...
KenoFischer 7y ago
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 7y ago
  What class is this?
  - KenoFischer 7y ago
    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 7y ago
      Lol what's the name of the biology class?
sokoloff 7y ago
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/
bcaa7f3a8bbc 7y ago
And remember that the author Sam Zeloof was still studying in highschool when he completed this project.
- DC-3 7y ago
  He must have tolerant parents to allow experiments involving baths of HF and Piranha solution in their garage! Seriously impressive though.
  - amelius 7y ago
    Or ignorant parents.
    - dymk 7y ago
      A highschooler don't end up with a garage full of equipment like that unless their parents are already in the industry.
      - faissaloo 7y ago
        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 7y ago
        He also purchased a decommissioned, broken electron microscope from a university lab on eBay, and repaired it by himself.
        deleted 7y ago
        [deleted]
        kokey 7y ago
phkahler 7y ago
Is this kind of thing possible with less toxic chemistry?
- esmi 7y ago
  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.htm http://www.hpfriedrichs.com/radioroom/cu-diode/rr-cu-diode.h...
- namibj 7y ago
  Not really. SiO2 is pretty inert, it's used as containment for most chemicals.
- faissaloo 7y ago
  There are some ideas floating about but nothing concrete and reliable just yet.
- syntaxing 7y ago
  It depends on what you mean. Typically you cannot get away from HF for the etching process but you definitely can replace the whole process with plasma etch/dep. Full plasma etch/dep fab line isn't really scalable and doesn't create optimal uniformity or layer thickness. But for a project like this, it's definitely doable minus the cost prohibitive equipment.
cr0sh 7y ago
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!
hammock 7y ago
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 7y ago
  > 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 7y ago
    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 7y ago
      We don't give people cars without a test. Perhaps such chemicals shouldn't be dispensed without training.
  - __jal 7y ago
    I don't know, but if I were doing this, I'd find out. Call your residential waste management company and ask them who handles commercial hazmat in the area, if you can't think of any other way to start. If you're planning out your own home fab, you're researching a bunch of other things and giving serious thought to a lot of nontrivial problems. Choosing to ignore waste disposal is irresponsible, and you deserve any legal hassle you run in to.
  - esmi 7y ago
bobcostas55 7y ago
Once space exploration really gets going, mobile chip fabrication is gonna be a pretty big deal.
- ngold 7y ago
  Good point. The space race would have massive benefits for us on earth in nanofabrication. Just one more bonus point for space.
  - ColanR 7y ago
    How does microgravity help in nanofabrication?
    - checktheorder 7y ago
      It may not be the microgravity that's the major help, but the hard vacuum. Deep space is the biggest, best clean room there could ever be.
      - lkschubert8 7y ago
        Wouldn't you have to deal with radiation that you are normally shielded from in Earth`s atmosphere? That may be more difficult to shield from than producing a normal clean room.
        checktheorder 7y ago
        I would bet that it's easier to design an orbital or moon-based structure (depending on whether production benefits from or suffers from microgravity) that's heavily shielded with lead, than it would be to create a deep-space-class hard vacuum in a volume of space on Earth suitable for large-scale industrial processes. It's a simple matter of not making the structure airtight. Given the volume and mass payload capabilities of the upcoming Starship/Superheavy, cheaply lifting bulk quantities of lead into space may actually be a reasonable proposal in the next five years rather than ultra-expensive pie-in-the-sky fantasy as it was during the age of disposable rockets.
otakucode 7y ago
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 7y ago
  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 7y ago
    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.
CodiePetersen 7y ago
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.
Taniwha 7y ago
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.
parsimo2010 7y ago
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.
droithomme 7y ago
Holy cow this is exceptionally impressive and amazing.
koskaj 7y ago
This guy makes me think of Kvothe in the Arcanum building sympathy lamps.
samrosea 7y ago
I knew this guy's brother lol.
weinzierl 7y ago
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.
dang 7y ago
Thread from 2018: https://news.ycombinator.com/item?id=16955549 https://news.ycombinator.com/item?id=16955549
rwmj 7y ago
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
craigr1972 7y ago
Another story that highlights why I absolutely love HN..
eternauta3k 7y ago
Now that MOSIS won't work with universities outside the US, this might be an interesting way to have very simple student designs fabricated.
bobjordan 7y ago
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

566 points by JabavuAdams 7y ago

gen3 7y ago

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

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 7y ago
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 7y ago
  >"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.
  - marcosdumay 7y ago
    > Is this specific to photography at this scale? Yes. A smaller scale makes it worse, a larger scale makes it better. If you reduce things enough, everything will become so blurred that you won't be able to see anything (that's why we can't photograph atoms using visible light), and if you make things large enough your camera will become the bottleneck so a very small amount of blur is added to any object, whatever the size.
    - bogomipz 7y ago
      Ah I see, when you say "photo" you are referring to the photolithography used in the chip making and not the captured photo of the finished chip is that correct?
      - marcosdumay 7y ago
        I mean the captured photography of the chip. Most of the time it is not done with ultraviolet light or electron microscopes, just with normal visible light cameras ans some very good lenses.
  - Kirby64 7y ago
    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 7y ago
      Thanks for the clarification. Agreed, given the scale of these they're pretty damn good :) Cheers.
- deleted 7y ago
  [deleted]
PhaseLockk 7y ago
I can't see the image you're referring to at the moment, but I imagine the fuzziness you are seeing is due to this fact: chips perform better if the features are smaller. Because of this, manufacturers want to make chip features as small as they can without causing failures, which means that you are manufacturing things at the scale that your manufacturing precision is barely sufficient, which means that the components look ugly, but they (mostly) work.
- fengazer 7y ago
  This. Every step in fabrication has limits on its resolution beyond the resolution of the machine exposing the polymer resist. The resist has a finite thickness (often comparable to the size of the feature you are trying to make). The developer solution works downwards through the exposed resist, but also outwards at the edges (where you will have some proximity effect in the exposure). Deposited metal or insulator sometimes sticks to both the bottom of the pit and the top of the resist without a clean break, or contains chunks or grains that make the coating uneven. Wet chemical etchants don't etch straight down, and often create rounded corners in cross-section. Every aspect of this has decades of optimization behind it, and its success in any one fabrication run is vulnerable to a frustrating number of variables. If there's an SEM cross-section of a device in a paper, it's likely because fabricating it was an accomplishment, and/or the design is in some way new (not ruling out other reasons of course: there's also "we have an SEM and not a lot else to put in the paper"). TL;DR: I agree. These things are very small and if we could make the corners sharper, that would remove one major barrier to making them even smaller. And then they wouldn't look so tidy anymore.
  - bogomipz 7y ago
    >"This. Every step in fabrication has limits on its resolution beyond the resolution of the machine exposing the polymer resist." I didn't quite understand what you meant here. Could you elaborate on this? What are some of those limits? >"These things are very small and if we could make the corners sharper, that would remove one major barrier to making them even smaller. And then they wouldn't look so tidy anymore." Aren't these contradictory? Did you mean to say "And then they would look so tidy"?
pjc50 7y ago
Necessarily it is operating at the limit of precision. If it wasn't blurry, you'd keep making it smaller until the blurring starts to become a problem again.
- fengazer 7y ago
  This sums it up best.
Junk_Collector 7y ago
As mentioned in other posts, the process of making these types of devices tend to produce rounded structures. This is a byproduct of using Ion beams, deposition, lithography, etc in manufacture. BUT, the image is also made worse by how the image is captured. The picture you are looking at is a FIB (Focused Ion Beam) cut cross-section of a transistor which is then imaged by a SEM (scanning electron microscope). Probably in one of their fancy dual source beam devices. Depending on how you cut with the FIB, you can also push material downwards into lower layers and create a waterfall effect that will blur edges. It's can be very noticeable in rookie cuts but doesn't look like a major impact here. Imaging with the SEM itself can also cause distortion and blurring as trapped charge accumulates on the surface and deflects the electron beam slightly. You can see this where the edges get increasingly bright because charges gather and become trapped at the boundary of the conductive and insulating layers. The image isn't sharp enough for me to tell if that is poly-silicon or aluminum contact traces.
- bogomipz 7y ago
  >"As mentioned in other posts, the process of making these types of devices tend to produce rounded structures. This is a byproduct of using Ion beams, deposition, lithography, etc in manufacture." Thanks for the detailed response. Might you have a link to one of those other posts or some other resources that talks about how these processes tend to produce rounded structures?
  - Junk_Collector 7y ago
    In the manufacturing process you have several methods that are used each with their own issues. Photo-lithography suffers from diffraction at the edges of features. Chemical processes undercut, overcut, and generally move around. They eat away faster at edges because of surface space and eat along different crystal lattice vectors at different rates. Plasma processes are effectively a hose of charged particles and have a sort of Gaussian distribution vs location of particle impact depending on your focus. And during the whole process, diffusion is trying to move everything around to boot. These effects exist at all scales, but when you get to IC scales, the effects can be dominant.

foobarbecue 7y ago

404 :-(

foobarbecue 7y ago
Woah, apparently this is because my workplace has added this website to the super-block-without-even-telling-you list...
- irq 7y ago
  I bet it's the .xyz tld that your workplace is blocking, but I don't know for sure of course.
- unethical_ban 7y ago
  I wish our infosec department would just trust the vendor reputation service and realize that gTLDs have been around for years now.
haspoken 7y ago
https://archive.is/http://sam.zeloof.xyz/category/semiconductor/ https://archive.is/http://sam.zeloof.xyz/category/semiconduc...

spectramax 7y ago

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

dbcurtis 7y ago
That looks very exciting for some research environments, and for some prototyping. But a 12mm wafer is certainly going to limit what you can do, and they make no mention of feature size. In the end, what you can accomplish is determined by the process and how easily your design tools let you target the process. I am sure there is a lot of academic research that could benefit greatly. As to prototyping, I have concerns that it would be difficult to do a part on this process and transfer it to a different process for scale.
LargoLasskhyfv 7y ago
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 7y ago

Avery3R 7y ago

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

KenoFischer 7y ago

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 7y ago
What class is this?
- KenoFischer 7y ago
  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 7y ago
    Lol what's the name of the biology class?

sokoloff 7y ago

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/

bcaa7f3a8bbc 7y ago

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

DC-3 7y ago
He must have tolerant parents to allow experiments involving baths of HF and Piranha solution in their garage! Seriously impressive though.
- amelius 7y ago
  Or ignorant parents.
  - dymk 7y ago
    A highschooler don't end up with a garage full of equipment like that unless their parents are already in the industry.
    - faissaloo 7y ago
      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 7y ago
        He also purchased a decommissioned, broken electron microscope from a university lab on eBay, and repaired it by himself.
        deleted 7y ago
        [deleted]
        kokey 7y ago

phkahler 7y ago

Is this kind of thing possible with less toxic chemistry?

esmi 7y ago
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.htm http://www.hpfriedrichs.com/radioroom/cu-diode/rr-cu-diode.h...
namibj 7y ago
Not really. SiO2 is pretty inert, it's used as containment for most chemicals.
faissaloo 7y ago
There are some ideas floating about but nothing concrete and reliable just yet.
syntaxing 7y ago
It depends on what you mean. Typically you cannot get away from HF for the etching process but you definitely can replace the whole process with plasma etch/dep. Full plasma etch/dep fab line isn't really scalable and doesn't create optimal uniformity or layer thickness. But for a project like this, it's definitely doable minus the cost prohibitive equipment.

cr0sh 7y ago

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!

hammock 7y ago

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 7y ago
> 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 7y ago
  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 7y ago
    We don't give people cars without a test. Perhaps such chemicals shouldn't be dispensed without training.
- __jal 7y ago
  I don't know, but if I were doing this, I'd find out. Call your residential waste management company and ask them who handles commercial hazmat in the area, if you can't think of any other way to start. If you're planning out your own home fab, you're researching a bunch of other things and giving serious thought to a lot of nontrivial problems. Choosing to ignore waste disposal is irresponsible, and you deserve any legal hassle you run in to.
- esmi 7y ago

bobcostas55 7y ago

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

ngold 7y ago
Good point. The space race would have massive benefits for us on earth in nanofabrication. Just one more bonus point for space.
- ColanR 7y ago
  How does microgravity help in nanofabrication?
  - checktheorder 7y ago
    It may not be the microgravity that's the major help, but the hard vacuum. Deep space is the biggest, best clean room there could ever be.
    - lkschubert8 7y ago
      Wouldn't you have to deal with radiation that you are normally shielded from in Earth`s atmosphere? That may be more difficult to shield from than producing a normal clean room.
      - checktheorder 7y ago
        I would bet that it's easier to design an orbital or moon-based structure (depending on whether production benefits from or suffers from microgravity) that's heavily shielded with lead, than it would be to create a deep-space-class hard vacuum in a volume of space on Earth suitable for large-scale industrial processes. It's a simple matter of not making the structure airtight. Given the volume and mass payload capabilities of the upcoming Starship/Superheavy, cheaply lifting bulk quantities of lead into space may actually be a reasonable proposal in the next five years rather than ultra-expensive pie-in-the-sky fantasy as it was during the age of disposable rockets.

otakucode 7y ago

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 7y ago
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 7y ago
  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.

CodiePetersen 7y ago

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.

Taniwha 7y ago

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.

parsimo2010 7y ago

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.

droithomme 7y ago

Holy cow this is exceptionally impressive and amazing.

koskaj 7y ago

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

samrosea 7y ago

I knew this guy's brother lol.

weinzierl 7y ago

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.

dang 7y ago

Thread from 2018: https://news.ycombinator.com/item?id=16955549 https://news.ycombinator.com/item?id=16955549

rwmj 7y ago

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

craigr1972 7y ago

Another story that highlights why I absolutely love HN..

eternauta3k 7y ago

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

bobjordan 7y ago

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