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Home Chip Fab

sam.zeloof.xyz

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Re: Home Chip Fab

#41

Post by LargoLasskhyfv »

LargoLasskhyfv wrote: post #36
spectramax wrote: post #6

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 blo…

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... 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 tes…

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

Re: Home Chip Fab

#42

Post by jefftk »

SkyPuncher wrote: post #22
hammock wrote: post #20

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.

> 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.

If you're in MA the link is: https://www.mass.gov/info-details/safely-manage-hazardous-ho...

Other states probably have similar things?

Very much worth researching before you get into a hobby where you start accumulating hazmats!

Re: Home Chip Fab

#43

Post by inferiorhuman »

SkyPuncher wrote: post #22
hammock wrote: post #20

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.

> 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.

I rarely see any actionable advice.

How's this? If you don't know how to safely dispose of the toxic chemicals used in chip fabrication don't fabricate chips at home.

Re: Home Chip Fab

#44

Post by amelius »

DC-3 wrote: post #35
bcaa7f3a8bbc wrote: post #14

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

He must have tolerant parents to allow experiments involving baths of HF and Piranha solution in their garage! Seriously impressive though.

Or ignorant parents.

Re: Home Chip Fab

#45

Post by ChuckMcM »

spectramax wrote: post #6

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 blo…

That is exceptionally cool. They have taken existing best practices in semiconductor fabs and migrated them to an interesting place.

What is missing of course is what their feature sizes are and the part at the end where you cut the die and package it. It is those things that would define the set of things you could put on a single chip.

Re: Home Chip Fab

#46

Post by adamnemecek »

KenoFischer wrote: post #8

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.

What class is this?

Re: Home Chip Fab

#47

Post by [deleted] »

Kirby64 wrote: post #10
bogomipz wrote: post #3

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 amorpho…

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…

[deleted]

Re: Home Chip Fab

#48

Post by bogomipz »

marcosdumay wrote: post #21
bogomipz wrote: post #17

Earlier quoted context omitted.

>"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…

> 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 t…

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?

Re: Home Chip Fab

#49

Post by ColanR »

ngold wrote: post #30
bobcostas55 wrote: post #27

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

Good point. The space race would have massive benefits for us on earth in nanofabrication. Just one more bonus point for space.

How does microgravity help in nanofabrication?

Re: Home Chip Fab

#50

Post by fengazer »

PhaseLockk wrote: post #11
bogomipz wrote: post #3

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 amorpho…

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 componen…

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.

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