A High School Student Building Integrated Circuits
spectrum.ieee.org
spectrum.ieee.org
I wonder what he is using to do metalization. There is the sputtering setup and the etching setup. Some nasty stuff involved in that. You can of course do quite a bit with polysilicon conductors but if he wants to do more useful things (as opposed to 'look it wiggles!' sorts of things) I'm guessing he will need some permits from the city :-). There is a reason nearly all the old fab sites in the bay area coincide with superfund cleanup sites :-(.
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.
There is a manual for it though (thanks abecedarious).
http://nanofab.caltech.edu/images/stories/classes/aph9/Aph9_...
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.
But his videos are very cool, and I'm looking forwards to more. I didn't realize he was that young.
There's maskless lithography, which is cheap, as far as those things go: https://en.wikipedia.org/wiki/Maskless_lithography
I was 17 at the time too, but doing it on your own is something else.
warning: I'm not advising you go home and start etching silicon oxide and cleaning wafers with vats of HF without doing adequate research and preparation to do it safely.
Working on a small scale, say 40 mm wafers, you’ll be dealing with small amounts of HF - approximately 250 ml. But.
There are two problems with HF: first, it doesn’t give a burning sensation like other acids, so there is a tendency to discount the seriousness of a major spill once you get past the shower off stage. Second, it is rapidly absorbed transdermally and causes an insidious necrosis, but, more importantly, it can affect blood potassasium balance and cause heart failure after some delay. While the emergency rooms on the peninsula are aware of the risk and the treatment, that may not be the case in rural Iowa. So do the homework, have a supply of gluconate on hand, and get to the emergency room right away (with the msds) if you wet, say, more than 50 sq cm of skin with HF. Not all people are susceptible, but EKG monitoring is essential following major bodily contact.
Always wear gloves, and test them. Since HF doesn’t give a burning sensation, it’s easy to get a small puncture and an HF burn. I remember one older tech who was lax about this and he lost fingernails over time. He would joke about soaking his hand in a bucket of water by his bed so he could get to sleep. Pioneer days!
It doesn't look as strong as the 2% solution PepBoys used to sell, though.
Very nice to see that the ieee is finally writing about his PCB fab setup!
Furthermore, Intel actually released the mask set for the 4004 many years ago: http://www.4004.com/mcs4-masks-schematics-sim.html
Another relatively "simple" early microprocessor that might be doable is a 6502, it also has the (reverse-engineered) mask layers available: http://visual6502.org/images/6502/index.html
Cutting-edge analog ICs are a different beast, though. Tightly controlled processes are the norm and post-fab trimming is common.
Then again I only tinker with discrete components so it's an area that's somewhat foreign to me.
In my opninion it would be easier to do interesting analog parts in a home lab than an interesting digital part. Making an opamp would be easier than a processor and more interesting than an XOR gate (around same # of transistors). Also, you can do some analog stuff with only NMOS or PMOS, which simplifies things by at least 50% compared to CMOS.
For a home lab, you care about process and characterization, but variation isn't as much of a concern because you won't be making that many. Also, just look at the development of the semiconductor industry. Early factories (making analog parts) didn't look that much different from what you could cobble together in a garage. By the time they were doing integrated processors, things were a lot more high-tech.
He should work with a lab like SNF/ANFF to make more advanced devices, you should be able to get access to one of the Raith E-beam machines for an acceptable price.
However, you can get reasonable quality masks for $150ish, and if you don't care about wafer yield, you can fit all of the layers on one mask. It's 1970s tech - 1:1 contact exposure, but you can hit a few microns.
https://www.reddit.com/r/creepy/comments/29jtyo/david_hahn_a...
Cause of death was fentanyl. Earlier comment: https://news.ycombinator.com/item?id=15470983
Wonder how he deals with the various solvents required as well, Silicon wafer production is notoriously dirty.
Edit: what makes you think he’s using phosphene?
Also, it seems to me he or people like him should try to make microcontrollers rather than "full" computer chips. I would buy something to drive blinky lights for $5.00 that ran 1/5 as fast as an Atmel chip to support a free chipmaking movement, but I can't see doing something for a general purpose computer chip (with the same ratios at least).
I found a more advanced digital application where the memory modules on our automatic titrator's exchangeable burets are fabricated on about a 5x20mm ceramic substrate and covered with the epoxy droplet with only the gold-plated connector pads showing. Only a limited byte capacity is needed, enough to contain the serial number and a line of variable text to store a couple user variables.
Small feature size and physical chips off of a multi-IC silicon wafer are not exactly essential for such a simple application.
This is something high schools need to be investing in, literally this is what is fueling our future, I think it's amazing, good job.
Yeah, heaven forbid anyone be treated that poorly.
His sister was also suspended from school for a bomb threat, so it seems to be a sort of recurring pattern with his family.