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 saw this video yesterday and considered posting it, but I wasn’t sure if it was appropriate for HN.
This channel has another video where it shows how the clean room lab is created starting from a basic backyard shed, and that was truly astounding. The positive pressure to keep the number of particles low in someone’s backyard is almost mystical to me.
You’re not sure if someone building a RAM clean room in a shed is appropriate for HackerNews, literally “news for nerds”? A dictionary purchase may be warranted
I think he plans to go far beyond just making RAM in that clean room. This is pure speculation, but I suspect the goal of that channel is to just make doom from scratch.
Given that the shed in this guy’s backyard is already approaching the entire national technological output of any country in the 1970s I think he may get there.
There's no mention of AGI, climate change, AWS outages, Trump, crypto schadenfreude or my new MVP that you should totally sign up for even though I just vibe coded it 20 minutes ago and the DNS hasn't fully propagated yet, but the API is amazing plz like comment and subscribe.
Ok, maybe I'm being a bit cynical. Stories about bikeable cities are welcome too. And wasn't Soylent popular for a hot minute back in the day?
Which is a pity, because lots of videos really need to be seen to be fully appreciated. Especially the ones showing stuff being made. And the ones that tend to show up here are usually worth the time.
I'm totally with the text folks on the 5 hour Fossdem sessions, though. Give me an accurate transcript I can grep or don't even bother.
I think if it's interesting to you then it's worth posting, and letting the voting system do it's thing. I only rarely post because by the time I've seen something it's usually already been posted
Recently I saw a post about Bonsai trees on the front page. Making your own RAM is 100% more relevant to HN than quite a few posts I see on the main page.
Technologies that were considered "high-tech" 20-30 years ago are now accessible to regular people. Making DRAM. I remember a video recently of a guy making his own floppy disks.
Next I expect people to manufacture integrated circuits that have been discontinued. Like the Z80
This is the most pathological technology I have heard of in a long time and I am not even going to apologize for upvoting and telling other people about the evil genius I found on the internet today.
So, I get that we charge the capacitor up, and that it leaks so we must recharge it periodically. I don't get two things:
1. How is the value read? Is it reading the leak?
2. How is recharging done? I guess the leak itself (assuming my guess in 1. holds) could provide charge for some logic that checks "if has charge then recharge else nop".
I still don't really get transistors :P, but this was cool.
You measure the charge (if it is there) before it is completely gone (if it were ever there). Capacitors always leak, these capacitors leak fast.
Measuring the charge also removes some of the charge -- fast, compared to the leak spead.
DRAM chips have a circuit that writes the value back -- charges the capacitor up if there's supposed to be a charge, drains it if there's not supposed to be a charge.
Refreshes and normal reads are the same, except that normal reads sends the value(s) to the output pin(s) on the chip.
He has "only" shown the basic grid of capacitors and transistors. The chip he shown has no circuit to measure charges or to write them back afterwards. This makes it easier to test the basic grip and the basic capcacitors.
Pretty sure the proper read out and write back circuit comes in the next video.
A transistor effectively is an AND gate. If there is a charge on both the source and the gate, then charge can move to drain. So if you charge up the capacitor and you connect it to the source of another transistor then you can check whether it is still charged by putting a charge to the gate and see if there is charge on the drain.
And you are right, that charge on the drain can then be used both to drive some logic and to activate the recharging of the capacitor that was just discharged.
By the way I am being handwavy about "charge" moving about, if you really want to learn the electronics it is more correct to call it a voltage relative to some ground that the charge always moves towards.
It turns out they intentionally drain a bit of the storage capacitor, and amplify that weak signal. Some of that amplified charge is then fed back to storage.
Is it? Looks like this video is "locked" on Patreon requiring "this post and more exclusive work. Join for $10/month" yet got, as of now, 329 611 views ... so are they just making $3M/month or is it not really working?
Backyard semiconductor production is pretty similar to backyard barbecue. Lots of heating, smoking (diffusion), injecting (ion implant), and layering..
There's another video on YouTube by the same guy detailing how he built his backyard clean room shed. I was kind of surprised at how easy it was - it's definitely a construction project that requires some specialized knowledge, but the fact that it's tractable at all for one person with a shed is pretty amazing to me.
Of course it not easy. He spent $20k on materials and a good amount of elbow grease just to construct this one room. In order to maintain the clean environment the air circulation runs 24/7 and he washes all the surfaces daily using cleanroom wipes. Deionized water system provides water for washing the cleanroom gowns. It is a lot of work just to have a small facility at home for odd jobs.
The furnace is a low cost off-the-shelf Chinese product from Anhui Beq Equipment Technology Co.
Much more impressive are the modifications to the microscope, transforming it into an improvised lithography machine, and the home made plasma etching machine, cobbled together from surplus components.
Of course, the whole thing, starting from the clean room, is extremely impressive -- Intel started their business in a much simpler facility.
The graphs towards the end were discharge curves for a single transistor/capacitor cell out of only 16 present, if I understood correctly? So "enough cells to count as memory" and "addressing logic" are definitely future work (it looked like he wanted to characterize what the refresh cycle would have to look like before actually building more.) I was kind of surprised that the "use a microscope as a photolithography projector" approach worked at all, it will be interesting to see how that scales up...
I get my DRAM needs at the RAM ranch.
18GB at a time
This channel has another video where it shows how the clean room lab is created starting from a basic backyard shed, and that was truly astounding. The positive pressure to keep the number of particles low in someone’s backyard is almost mystical to me.
Given that the shed in this guy’s backyard is already approaching the entire national technological output of any country in the 1970s I think he may get there.
Ok, maybe I'm being a bit cynical. Stories about bikeable cities are welcome too. And wasn't Soylent popular for a hot minute back in the day?
Indistinguishable From Magic: Manufacturing Modern Computer Chips
https://www.youtube.com/watch?v=NGFhc8R_uO4&t=2070s
It's quite old but I think there is no modern version of it.
I've tried posting to HN a few times but it hasn't gained traction for some reason, but I find it absolutely mind blowing.
Maybe it’s just I come here for the old web feel when video was costly, rare and short.
I'm totally with the text folks on the 5 hour Fossdem sessions, though. Give me an accurate transcript I can grep or don't even bother.
https://downloadmoreram.com/
1. How is the value read? Is it reading the leak?
2. How is recharging done? I guess the leak itself (assuming my guess in 1. holds) could provide charge for some logic that checks "if has charge then recharge else nop".
I still don't really get transistors :P, but this was cool.
Measuring the charge also removes some of the charge -- fast, compared to the leak spead.
DRAM chips have a circuit that writes the value back -- charges the capacitor up if there's supposed to be a charge, drains it if there's not supposed to be a charge.
Refreshes and normal reads are the same, except that normal reads sends the value(s) to the output pin(s) on the chip.
He has "only" shown the basic grid of capacitors and transistors. The chip he shown has no circuit to measure charges or to write them back afterwards. This makes it easier to test the basic grip and the basic capcacitors.
Pretty sure the proper read out and write back circuit comes in the next video.
And you are right, that charge on the drain can then be used both to drive some logic and to activate the recharging of the capacitor that was just discharged.
By the way I am being handwavy about "charge" moving about, if you really want to learn the electronics it is more correct to call it a voltage relative to some ground that the charge always moves towards.
It turns out they intentionally drain a bit of the storage capacitor, and amplify that weak signal. Some of that amplified charge is then fed back to storage.
RAM at home:
Much more impressive are the modifications to the microscope, transforming it into an improvised lithography machine, and the home made plasma etching machine, cobbled together from surplus components.
Of course, the whole thing, starting from the clean room, is extremely impressive -- Intel started their business in a much simpler facility.