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Registration wall. Does the article say what he does with HF? Ive often thought home brew chip making at 70s scale would just be a lot of elbow grease, but def

Registration wall. Does the article say what he does with HF? Ive often thought home brew chip making at 70s scale would just be a lot of elbow grease, but definitely doable. Safety is not that hard. Chemicals not that bad. Nothing that American garage tinkerers haven't dealt with before (my favorite, tin can turbine) Except for the HF. Ill admit I dont know much about HF, I used it only once in a lab (making BJTs) but: HF is nasty dangerous, impossible (?) to get without a license, impossible to dispose properly. Is there an alternative to etch SiO2 or is this guy on the edge of legal and insane?

moring 5y ago
Flourides might work, because they set HF free at a low rate. I always wanted to try SiO2 etching with ArmourEtch (glass etching paste, i.e. flourides) but got sidetracked. There might be other problems with that specific paste, for example I don't know if it contains abrasives, but if you have access to a chemical lab then flourides should be easy to obtain. AFAIK the chip industry uses flourides too (buffered oxide etch) because unbuffered HF has a too unpredictable etch rate.
kortex 5y ago
HF is scary but not that insane and not impossible to get without a license (in the US). You can get kits to etch glass which contain in-situ HF (armor etch for example). You can produce your own by obtaining fluoride salts and adding acid - though I would NOT recommend doing this without having some sort of lab chemistry training. There's a line between "demands respect and thought during handling" and "reckless/insane". Having a properly ventilated workspace, and knowing how to handle dangerous chemicals, I would say HF is dangerous but not insane. Borderline insane for a hobbyist would be things like generating primary explosives/peroxides or toxic gases: cyanides, phosphines, hydrogen sulfide, ketene. I worked as a lab chemist for years and even with a decent home lab, I would be loathe to do any experiments which generates toxic gases in anything greater than 100's of mg quantity, because discharging your vent hood becomes a big concern. I've heard stories where someone accidentally acidified some cyanide (in a hood) and it killed a bunch of pigeons on the roof. HF, eh, that's fume hood and PPE territory. Neutralize with calcium hydroxide, evaporate it in a hood to salt, and dispose as you would other solid chemical waste. It's just fluorite mineral at that point.

moring 5y ago

Flourides might work, because they set HF free at a low rate. I always wanted to try SiO2 etching with ArmourEtch (glass etching paste, i.e. flourides) but got sidetracked. There might be other problems with that specific paste, for example I don't know if it contains abrasives, but if you have access to a chemical lab then flourides should be easy to obtain. AFAIK the chip industry uses flourides too (buffered oxide etch) because unbuffered HF has a too unpredictable etch rate.

kortex 5y ago

HF is scary but not that insane and not impossible to get without a license (in the US). You can get kits to etch glass which contain in-situ HF (armor etch for example). You can produce your own by obtaining fluoride salts and adding acid - though I would NOT recommend doing this without having some sort of lab chemistry training. There's a line between "demands respect and thought during handling" and "reckless/insane". Having a properly ventilated workspace, and knowing how to handle dangerous chemicals, I would say HF is dangerous but not insane. Borderline insane for a hobbyist would be things like generating primary explosives/peroxides or toxic gases: cyanides, phosphines, hydrogen sulfide, ketene. I worked as a lab chemist for years and even with a decent home lab, I would be loathe to do any experiments which generates toxic gases in anything greater than 100's of mg quantity, because discharging your vent hood becomes a big concern. I've heard stories where someone accidentally acidified some cyanide (in a hood) and it killed a bunch of pigeons on the roof. HF, eh, that's fume hood and PPE territory. Neutralize with calcium hydroxide, evaporate it in a hood to salt, and dispose as you would other solid chemical waste. It's just fluorite mineral at that point.