4 ms·

I worked in small scale fabs back in the day. One and a half inch wafers. It’s not nearly as hazardous as you make out, but it does require training in chemistr

I worked in small scale fabs back in the day. One and a half inch wafers. It’s not nearly as hazardous as you make out, but it does require training in chemistry. I’m a physicist, but I also did a pre-med, so I had the necessary chemistry background to be safe. Sputtering requires a small amount of high vac equipment - diffusion pump plus LN cold trap is fine. Sputtering titanium plus gold is straightforward and non-toxic. Etching the pattern requires small amount of aqua regia, which is, of course, a strong acid, but can be easily neutralized to non-toxic by-products. Aluminum evaporation and etching is even easier. The complexity and cost comes in four areas: nanoscale features, large wafers, high throughput, and a process that doesn’t need professional chemists to perform.

kurthr 9y ago
Yeah, but doing it without a lab makes it a lot more difficult to do safely and with multiple likely dangerous (toxics, oxidizers, mutagens) byproducts (including the Si dopants) doing it at home is sketchy. Could one person do it in something the size of a garage? Yes, I think 20-40 probably do every year in a university clean room. But building that for a single person is an exercise in both chutzpah and perhaps (toxic) waste. It's a lot more tempting to cut safety corners when you're doing it for the first time, and haven't made THAT mistake yet. There is a manual for it though (thanks abecedarious). http://nanofab.caltech.edu/images/stories/classes/aph9/Aph9_Manual_CurrentVerNov2014.pdf http://nanofab.caltech.edu/images/stories/classes/aph9/Aph9_...
- wrycoder 9y ago
  Absolutely right. This isn't something anyone should even contemplate in the kitchen! If they are thinking about it, then they don't know what they don't know. Experience in chemistry is needed, and that's unfortunately a lot rarer now in the US than it was 50 years ago. People (and governments) have developed a (mostly unwarranted) fear of it. The minimum processing requirement (aside from the furnaces and metallizing equipment etc.) is a polyethylene sink hood with at least 100 ft per min flow and a neutralizing tank connected to the drain line, along with fume exhausted chemical storage below. If you can't acquire or build that, you shouldn't proceed further. I did a lot of commercial work in a three foot hood with a large Corning hotplate. You also need an arrangement to recycle your organic solvents.
  - Pica_soO 9y ago
    People are not this dumb- they have come to associate large scale chemical (aka chemistry) processing with environment and health issues- and although nobody in the various industries likes to hear it- they are usually right. Every city has some paved over "dead" zone from the 50s and 60s, before we learned to offshore the burden to third world countrys.

kurthr 9y ago

Yeah, but doing it without a lab makes it a lot more difficult to do safely and with multiple likely dangerous (toxics, oxidizers, mutagens) byproducts (including the Si dopants) doing it at home is sketchy. Could one person do it in something the size of a garage? Yes, I think 20-40 probably do every year in a university clean room. But building that for a single person is an exercise in both chutzpah and perhaps (toxic) waste. It's a lot more tempting to cut safety corners when you're doing it for the first time, and haven't made THAT mistake yet. There is a manual for it though (thanks abecedarious). http://nanofab.caltech.edu/images/stories/classes/aph9/Aph9_Manual_CurrentVerNov2014.pdf http://nanofab.caltech.edu/images/stories/classes/aph9/Aph9_...

wrycoder 9y ago
Absolutely right. This isn't something anyone should even contemplate in the kitchen! If they are thinking about it, then they don't know what they don't know. Experience in chemistry is needed, and that's unfortunately a lot rarer now in the US than it was 50 years ago. People (and governments) have developed a (mostly unwarranted) fear of it. The minimum processing requirement (aside from the furnaces and metallizing equipment etc.) is a polyethylene sink hood with at least 100 ft per min flow and a neutralizing tank connected to the drain line, along with fume exhausted chemical storage below. If you can't acquire or build that, you shouldn't proceed further. I did a lot of commercial work in a three foot hood with a large Corning hotplate. You also need an arrangement to recycle your organic solvents.
- Pica_soO 9y ago
  People are not this dumb- they have come to associate large scale chemical (aka chemistry) processing with environment and health issues- and although nobody in the various industries likes to hear it- they are usually right. Every city has some paved over "dead" zone from the 50s and 60s, before we learned to offshore the burden to third world countrys.