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Home Chip Fab

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Re: Home Chip Fab

#101

Post by j88439h84 »

henryfjordan wrote: post #23
SkyPuncher wrote: post #22

Earlier quoted context omitted.

> 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.

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.

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

Re: Home Chip Fab

#102

Post by NikkiA »

klyrs wrote: post #91
checktheorder wrote: post #81

Earlier quoted context omitted.

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.

The thought of handling toxic, corrosive liquids in zero gravity is terrifying.

Not just corrosive, but calcium devouring.

Re: Home Chip Fab

#103

Post by tfha »

LargoLasskhyfv wrote: post #84
ChuckMcM wrote: post #78

Earlier quoted context omitted.

Ok thanks for that. So 500 nm today, moving to 250 nm by the end of the year or early next year. So your 12.5mm wafer can have a 8.8 x 8.8 mm square inside of it, or 78.125 mm^2. If I did the math right that is on the order of 156M transistors given a 4t ram cell that is about 39 million bits of RAM. So basically a pretty useful amount of space for "jelly bean" type applications. A synchronized fab line with a median…

Here is a PDF from 2017 from someone involved with a project wich seems to intend to use this in an (large scale?) innovation initiative in Japan. [1] www.lip6.fr/public/2017-03-17_Shimizu.pdf Mentioned are workflows, used tools, intendend audience and goals, estimated prices, nda-freeness of spice models and design rule check, open source, open-cores, github, and so on. If they really make this widely available, the…

That would be amazing!

Re: Home Chip Fab

#104

Post by wrycoder »

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.

I ran a small fab on the peninsula back in the day, and we certainly didn't dump any trico down the drain. We did put a small amount of propanol (used to switch from a water rinse to trico drying) down, but that's pretty harmless. The trico was taken away by a reprocessing company. It was still essentially pure - some of it contained a bit of dissolved photoresist or beeswax.

I read through the OP - he's making good choices and doing it much as we did fifty years ago. I would have killed to get that maskless photolith setup, though.

For a small fab (three furnace tubes, two fume hoods), the main issue is acids from photoresist ashing, wafer cleaning, tube etch cleaning, and metal etching. These are easily neutralized with a vat of marble chips built into the plumbing under the fume hoods.

If you are doing this, avoid epitaxy, which involves arsine and phosphine. I would say never attempt those! You can buy epi wafers. Either use spin-on dopants like he did, or use oxidized boron nitride wafers and small amounts of phosphorous oxychloride like we did.

The effluent from a plating facility or a dry cleaning establishment would be far more concerning.

Our furnace and photolith operation fit in a 20 x 30 ft room. It was one of the leading operations of its kind in the world at that time.

Re: Home Chip Fab

#107

Post by kragen »

droithomme wrote: post #98
hinkley wrote: post #86

Earlier quoted context omitted.

First warning with neutralizing acids: You're going to release a lot of heat, make sure you have a large thermal mass to absorb it. Someone else mentioned mixing your ingredients with water first. This is why. From what I understand the last thing you want to experience is an explosion of hydrofluoric acid. The internet seems to suggest lime (->fluorspar) or soda lye (->NaF, used for fluoridating water) to neutralize…

Yeah if you just dump a base into these strong acids things go foom! and you end up with dead makers. Don't mix this stuff in dilution in an enclosed space either as the H2 gas can create another explosion hazard.

HF is technically a weak acid, but I wouldn't venture to neutralize it quickly; it's very reactive even if it doesn't fully dissociate in water.

As for hydrogen, neutralizing acids with bases doesn't generally produce it, but ventilation is still a good idea.

Re: Home Chip Fab

#108

Post by unethical_ban »

foobarbecue wrote: post #5
foobarbecue wrote: post #4

404 :-(

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

I wish our infosec department would just trust the vendor reputation service and realize that gTLDs have been around for years now.

Re: Home Chip Fab

#109

Post by 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.

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