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by keysersoze33 60 days ago
Admit it, deep down, our inner engeering child also wants to build a semiconductor clean room ;)
2 comments

I do but my days in the fab taught me that you do NOT want people to do this, considering the extremely dangerous chemicals involved. People have died changing EMPTY tanks of phosphine gas used for doping… and HF acid used for etch is another nightmare entirely.
I used to graduate at an institute having physicists as well as chemists, I gues it was no coincidence that only physicists operated with HF, one chemist told me that no chemist in their right mind would touch it
That's not quite accurate (but close enough). We had HF in the chem lab. It lived in a dedicated metal box with a massive neon warning label and a padlock.

It's notable in comparison that all the deadly organics lived together in an unlocked cupboard (vented OFC). I think the only thing I ever saw treated as more of a pariah than HF were radioactive isotopes. Those generally get an entire dedicated room with restricted entry and a tedious mandatory cleaning procedure.

Makes sense. HF deserves the same awe as radioactive material. I've always found both fascinating. Like some kind of dark magic that curses you if you contact it.
As usual for particularly nasty crap, Derek Lowe has written amusingly about why he won't work with it[1].

[1] https://www.science.org/content/blog-post/things-i-won-t-tou...

HF is routinely used in analytical labs; it's standard to microwave HF solutions for ICP digestions. It's not even the most hazardous reagent in my lab right now.

Now, perhaps this chemist meant that no chemist in their right mind would physically touch HF--in that case, I agree completely!

AFAIK they're talking about anhydrous HF gas, not solutions of it. That sounds substantially less fun to work with. It's used to clean CVD chambers.
Oh fair enough, that is a nightmare.
Oh, my dream clean room is of course fully robot automated and I can watch through a big (safety) window.
Knowing that really helps you understand just how valuable semiconductors are as a product.
In my journey to make pcb’s at home I decided to stop once I almost gassed myself and shifted instead to buying gpus
I visited a pcb making factory once. Left with an appreciation for the amount of work needed for 80-layer pcbs, and knowing I would not want to deal with making them myself.
my goal was simple 2 sided pcbs, machined traces because i wanted to avoid chemical etching, but when it comes to via's chemicals are really the only way. The chemcials needed for plating via's are very toxic. my current thinking to avoid the really nasty ones is to try conductive ink (probably pretty bad too) but it maybe would work to coat the fr4 material and then allow a copper plating to take... really it's a fun process machining and laser the soldier mask.
I'm all for safer and less error prone processes, if there is a conductive ink safe for home use, just sell me a 3D printer that does it.
I keep thinking that for home tinkering this is really the wrong approach. Surely there are other more DIY-friendly ways to make switches besides with semiconductors? Sure, they wouldn't achieve anywhere near the same density as SOTA semiconductors, but that's not really possible at home anyway.
I guess you could always go back to electromechanical relays. I wonder if it might be possible to come up with a method of 3D printing those?

But in practical terms the Z80 was a 4 um process node so unless you're willing to go back to the proverbial stone age it seems like you need semiconductors and lithography.

It is only half as bad as working in the places that make tbose chemicals for use in clean rooms. Swaping out "empty" phosphine tanks is bad, but filling and shipping hundreds of full tanks is worse.
This is the issue I have with people saying that solar power is "clean and eco friendly".

It sure is, if you ignore the fact that you have to have a factory to make it where one of the *nicest* things around is the fucking hydrofluoric acid, and most of the rest will kill you instantly in trace amounts.

The technology is, the production is not but you can contain that, at least in theory. Compare that with gasoline that everytime you obtain energy from it you burn it out of existence and create a mess of the environment.
This is why we should have converted all the cars to run on propane, instead of scrapping them in favour of "cleaner greener diesels" 20 years ago when they started all the "scrappage scheme" bollocks.

The propane is going to get burnt anyway. May as well extract some useful work from it, and when you run a car off it they become ultra low emission.

Honest question, is there a way to run the entire process acid-free?
No. Silicon oxide (glass) is extremely tough from a chemical perspective. That's why it's used in chemistry for everything. Barely anything touches it. Also this is the main reason I think that the meme of "silicon based life" is completely absurd and comes from people who only took high school chemistry and built their worldview on that.
Is it conceivable that some organic solvent could be synthesized that is, simultaneously harmless to water-based biological life, and capable of etching Silicon oxides?
Not really. Organics don't really have any affinity for this type of compound. You could, of course, create some kind of organic fluorinating compound, but it would basically just put you back at square one for safety.
No acids at all? That would be stupendously difficult for no real benefit. So many things are acids, so many useful reactions involve acids, and there's not a significant correlation between "is an acid" and "danger".
yes acids capable of etching = danger :) aktschually
While that would be cool, something like the 7400 series, is already pretty close to scratching that itch. And a lot less dangerous.