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A home-made lithographically-fabricated integrated circuit

sam.zeloof.xyz

61–70 of 122 posts

Re: A home-made lithographically-fabricated integrated circuit

#61
post #48
post #22

Earlier quoted context omitted.

Of course, caution is always warranted when dealing with HF. However, I don't see any reason why it can't be safely used at home. In fact HF is found in lots of commonly used household cleaning products like rust and stain removers. Plenty of people are using Goof Off Rust remover and are not dropping dead later in the day.

That's akin to saying water-guns aren't very dangerous therefore shotguns are safe to play with.

Water guns are far more dangerous than shotguns given the things you can put into them.

Re: A home-made lithographically-fabricated integrated circuit

#62
post #12

Awesome. For those considering exploring some of these steps in their own garage -- the chemistry is dangerous, perhaps HF in particular, as it doesn't hurt, it just kills you a few hours later. Can you do this in a garage? Absolutely, but learn everything you need to know from an ensemble of safety-minded mentors before you strike out on your own. It's not just about safety for you, proper disposal of these chemical…

>> For those considering exploring some of these steps in their own garage -- the chemistry is dangerous, perhaps HF in particular, as it doesn't hurt, it just kills you a few hours later. I was hoping that with 50 years of development behind us, the home fabricators could use less complex methods and less hazardous chemicals. In other words, can the folks who lived it help people like this by saying "If we had to do…

I used to work in a fab. As far as I know, there's no acceptable way to remove native oxide without HF. We do have another etch process -- dry etch -- that uses plasma instead, but it causes surface damage, and you don't want that under the gate. Also, dry etch chambers are a lot more work to maintain than a fume hood where you do wet etch. Furthermore, dry etch has its own set of hazards, and you have to deal with a lot more potentially toxic vapor.

Re: A home-made lithographically-fabricated integrated circuit

#63
post #33
post #12

Awesome. For those considering exploring some of these steps in their own garage -- the chemistry is dangerous, perhaps HF in particular, as it doesn't hurt, it just kills you a few hours later. Can you do this in a garage? Absolutely, but learn everything you need to know from an ensemble of safety-minded mentors before you strike out on your own. It's not just about safety for you, proper disposal of these chemical…

Nice HF technical overview: https://ehs.unc.edu/files/2015/09/hydrofluoricacid.pdf (tldr; nope; read it.) I needed to dissolve(ha!) fluorite once. You can get it started by adding a few drops of conc H2SO4 to your beautiful aqua regia solution. It goes deeper red, some happy bubbles appear, and as long as it stays put, makes it's own "aqua nasty"(pg88) as you gently add your powdered sample. I thought AQR+SA was call…

If I remember correctly in the book: "1636: The Chronicles of Dr. Gribbleflotz" he made "aqua regia" from "aqua fortis" and "acidum salis" I don't know if either of those were his name for aqua-regia + HydroSulphuric Acid. I know he called ethanol "aqua vitae" by repeatedly distilling wine. He also had "Oil of Vitriol" which he added to saltpeter to make "aqua fortis". He also talked about adding "Oil of Vitriol" to "aqua fortis" but doesn't say what it makes. I think maybe "oil of vitriol" was hydro sulfuric acid, but I am not sure. Perhaps you can find more or someone else can remember. (I used: https://www.ericflint.net/index.php/2016/06/03/1636-the-chro... to quote what I mentioned here.)

Re: A home-made lithographically-fabricated integrated circuit

#64

Earlier quoted context omitted.

[5:16] "...oh, I didn't die having go in there messing with the hydrofluoric acid. My bones do feel a little gelatinous though." I'm not sure if I should admire or condone this kind of attitude in a science related context.

> I'm not sure if I should admire or condone this kind of attitude in a science related context. It makes no difference whatsoever to the whole what you’ve pointed out here. Throughout the video, she states she’s responding to critics. Her whole attitude is of teasing those who accuse her of not knowing what she does (calling her chips fake, etc). When she says that, it’s perfectly clear that she’s being very (and I…

Normally I would agree with you. But these days when anyone can find support for, as well as buy, almost anything on the Internet our freedom to be imprecise and still responsible has unfortunately diminished significantly. That of course doesn't justify a lot of other comments, or attitudes, people have to deal with when wanting to make something.

Re: A home-made lithographically-fabricated integrated circuit

#65

Earlier quoted context omitted.

>> For those considering exploring some of these steps in their own garage -- the chemistry is dangerous, perhaps HF in particular, as it doesn't hurt, it just kills you a few hours later. I was hoping that with 50 years of development behind us, the home fabricators could use less complex methods and less hazardous chemicals. In other words, can the folks who lived it help people like this by saying "If we had to do…

I used to work in a fab. As far as I know, there's no acceptable way to remove native oxide without HF. We do have another etch process -- dry etch -- that uses plasma instead, but it causes surface damage, and you don't want that under the gate. Also, dry etch chambers are a lot more work to maintain than a fume hood where you do wet etch. Furthermore, dry etch has its own set of hazards, and you have to deal with a…

Thinking a little more outside the box, you might look into using germanium instead of silicon. I don't know much about the germanium system, except that it supposedly grows less oxide. You're still going to have to deposit and remove oxide somehow, though, which means CVD reactors and silane. It's not going to be easy to get away from explosive toxic gases and dirty processes.

Re: A home-made lithographically-fabricated integrated circuit

#66
post #12

Awesome. For those considering exploring some of these steps in their own garage -- the chemistry is dangerous, perhaps HF in particular, as it doesn't hurt, it just kills you a few hours later. Can you do this in a garage? Absolutely, but learn everything you need to know from an ensemble of safety-minded mentors before you strike out on your own. It's not just about safety for you, proper disposal of these chemical…

And then you have Phosphene gas used to dope silicon, where people have died changing empty supply tanks.

The exhaust lines on high-energy implanters (the ones that do P doping) are a treat. They get coated up with deposits of solid phosphorus. If accidentally exposed to atmosphere, they do what phosphorus does. We used to call it "unscheduled exhaust system PM." Medium and high current implanters where I worked accumulated arsenic in the exhaust system, but at least that doesn't explode on you.

Re: A home-made lithographically-fabricated integrated circuit

#67
post #61
post #48

Earlier quoted context omitted.

That's akin to saying water-guns aren't very dangerous therefore shotguns are safe to play with.

Water guns are far more dangerous than shotguns given the things you can put into them.

Like, for example, HF.

Re: A home-made lithographically-fabricated integrated circuit

#68
post #12

Awesome. For those considering exploring some of these steps in their own garage -- the chemistry is dangerous, perhaps HF in particular, as it doesn't hurt, it just kills you a few hours later. Can you do this in a garage? Absolutely, but learn everything you need to know from an ensemble of safety-minded mentors before you strike out on your own. It's not just about safety for you, proper disposal of these chemical…

Thanks for saying this. I worked for a few years at a semiconductor fab r&d facility. (As a tenant) Seemingly everything associated with this stuff is toxic and polluting. The old timer war stories include stuff like accidental releases that stripped paint from all of the cars in the adjacent lot.

Nasty stuff — the wisdom promoting garage stuff like this is questionable. :)

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