Second IC

Is DMSO really a replacement for acetone in most applications?

His achievements are great, but the only reason why he could this without a cleanroom and with less pure chemicals is that he succeeded to find on eBay a batch of silicon wafers with the MOS gate oxide already grown on them.

Growing the MOS gate oxide without extreme cleanness has no chance of succeeding.

The difficulty of this process has caused a delay of many decades between the time when the MOS transistor was first imagined (in 1928 by Julius Edgar Lilienfeld, then also in 1935 by Oskar Heil) and the time when working MOS transistors were made for the first time, around 1960.

A class 10000 clean bench might be more practical. A lot easier to keep your cleanroom clean when the humans are outside of it, just sticking gloved arms in from time to time.

Be careful about purifying alcohol. Some backward countries have religiously-based legal prohibitions on this. My own backward country tightly controls acetone as a "precursor" to "stupefacients".

Nice thing about silane is that you don't have to worry about accidentally breathing it. There's a cheap and simple process for manufacturing it on demand from magnesium silicide, so you don't have to store it either.

> With some work, and a ton of HEPA air purifier machines, you could probably turn an area the size of a small shed or 1 car garage into a class 10000 cleanrom pretty easily.

I wonder if it would be possible to automate the entire process with robotics and reduce the effective "clean" space even further.

There was this post a while back about a company that used thin cassettes to keep the wafers clean when moving between process steps.

I was thinking about something like that too. How hard would it be to have a semiconductor-manufacturing-as-a-service with lower inertia like those PCB manufacturing services? The hobbyist affordable board houses these days generally have extremely good processes and quality that even beat some "industrial" board houses, as they're thoroughly refined by fabricating hobbyist boards with sometimes really awful DFM considerations

It's not strictly semiconductor-related, but if there's one thing I would like to see, it's low cost, made-to-order integrated analog computers. The low power consumption of analog devices would offset the larger feature size, and hopefully the process could be made cheap/flexible enough so that needing a different IC design for each use case would be a non-issue.

We have that problem of trusting our compilers, and the guys that are trying to build a completely clean bootstrap of gcc (?). The ability to manufacture some known-safe hardware might help that project.

> There has got to be something better than the semiconductor industry we have today, which has ridiculous barriers to entry.

I am curious about your exact meaning. When you say barriers to entry, it sounds like you're implying the "semiconductior industry we have today" is actively putting up barriers to prevent you from entering? Is that what you are trying to say? If so, please elaborate so that we can understand what these barriers you are facing are.

Or is it just that you're acknowledging that it actually costs many billions to build up a commercially viable fab?

I imagine this will end up like 3D printing though.

A 3D printer is fantastic to prototype your own designs. Or to build custom parts in low volume.

But it will never replace traditional manufacturing at scale. And even CAD is a massive barrier to entry.

And 3D printing is far more useful for everyday things but we still haven’t figured out a model to make the technology accessible to the general public.

This is a very impressive project though. I’m envious.

Turning old processes into a startup is what Melexis did 30+ years ago: they acquired obsolete fabs in Eastern(?) Europe and repurposed them to make sensors, which don’t need state of the art processes.

The 180nm open source eFabless shuttle runs that are sponsored by Google are done by X-fab, which is owned by Melexis’ founder as well.

I don’t see how this garage stuff (impressive as it is!) can be turned into a startup. It’s not as if there is some kind of breakthrough here?

I don’t know the minimum amount equipment needed to make these chips, but his garage is stuffed with old but still expensive equipment (if you need to buy it on eBay.) Things like a wire bonder, an electron microscope, a vacuum chamber etc.

I think that most of these were donated to him though.

His lab would cost a fortune if you were buying the equipment new from the manufacturer. But he has been able to source a lot of decommissioned semiconductor fab equipment through eBay and donations etc. Like his wire bonding machine. He has spent years of effort setting it all up, so it's not something for a one off project.

But replicating his simpler transistor experiments should be doable on a smaller budget. Also check out Jeri Ellsworth's DIY transistor project. Some nasty chemicals and special equipment is necessary but nothing too much for a hobbyist.

I believe Sam avoids using anything that's super awful to deal with. There's well defined procedures for taking care of most chemicals that involve neutralizing them sufficiently to be flushed down the drain

The "HF" doesn't stand for "high five!"?

I recently visited the Berkeley Nanolab. As I recall, the main waste products are either acids that are neutralized before being returned to the city sewer system, or exotic gases that are vented in dilute enough quantities to be safe.

This is all going to depend on exactly how much $$$ you have to spend. The major step-wise jumps in cost can usually be attributed to higher resolution photo techniques and the precision tools required.

Most of the other processes can theoretically be carried out at garage-scale, as the precision is more about chemistry than dimension or scale.

I'm thinking about trying to take this on myself, after watching and reading everything from Sam and Huygens Optics, and going through Chris Mack's course online.

I think the problems for offering any kind of hardware solution for this is that everything involved is either "pretty easy" or "pretty darn hard".

A decent UV laser, a workable optics bench, and 3/4 of the process chemicals are cheap and readily available. You can even build a "clean enough" fume hood. The processes are decently documented already in an open way.

Super high precision 3x axis closed loop micrometer or piezo stages, a wire bonder, and good quality pre-layered wafers are so far beyond small distributor or hobbyist scale that they're relegated to elusive Ebay scores. The other 1/4 of the process chemicals require getting a big distributor like Sigma to work with you, and some of them really require chemistry training to work with safely, although it's great to see some of the workarounds. I believe Jeroen at Huygens Optics is a chemist by training. He's comfortable working with things like HF that you really don't want to promote to amateurs, but are essential to get past a few thousand transistors.

Getting a complete process beyond the 70s era stuff at an amateur level is probably impossible right now. The absolutely insane requirements for silicon growing/cleaning alone are just more than one person can fit in their head, or their garage.

I'd compare it to large liquid fueled rocket engines, which are another common nerd dream project. Plenty of people understand the principles, and a few college teams or the equivalent have built working ones, but there's probably just too much to know and understand to do it solo and with no serious budget.

To make the economics work, you'd probably want to pool funding & run many wafers. Perhaps you could develop the world's first MaaS venture (Manufacturing As A Service)?

Isn't that what FPGAs are good for?

It's time for some big software companies like Google to commoditize their complement. So who knows ...