How to make your very own semiconductor-class cleanroom in a wooden shed and build your own chips, well kinda

OK, everyone relax. You know this chip-making malarkey that's pushing the stock prices of companies like Nvidia, ASML and TSMC into orbit, in part thanks to the AI boom and resulting chip crisis? It isn't so complex after all. Someone's built a semiconductor-class cleanroom in a wooden shed in their backyard. DIY chip building, here we come, people.Well, kinda. There might be a few more hurdles to vault once the cleanroom itself is sorted, but hold that thought. As spotted by Hackaday, the aptly monikered YouTube channel Dr.Semiconductor takes us through a backyard cleanroom build, and it turns out not to be nearly as difficult as you might think.Cleanrooms, in a modern chip-manufacturing context, are typically located inside huge factories comparable in size to a sports stadium. They're essentially large spaces within the factory walls containing manufacturing tools and very clean air where chips are actually produced. A single tiny spec of dust can ruin a whole chip, so scrubbing the air in these facilities is absolutely critical. Not to overemphasise the point, but the air needs to be incredibly clean.You might, therefore, think that a plain wood shed in someone's garden is an inauspicious start. Surprisingly, it seems you'd be wrong. Dr.Semiconductor used mainstream and widely available materials for the build.We're talking insulation, framing to support HEPA filters, heating and cooling kit, and so on. Inside the wood shed, some dry wall (known as plasterboard in the UK) makes up the cleanroom structure, coated in epoxy for a smooth, particle-free surface. Two zones are required: a "gowning" area and the cleanroom itself. You can't just walk straight into a clean room, you "transition" into it.

But the main trick is positive air pressure. This means the air pressure inside the clean room is higher than the outside world, preventing air and thus contamination from entering. This is done using "cleanroom grade" HEPA air filters to scrub air inside the clean room and also pull a little from the outside and scrub that to sustain the positive pressure. Air in the cleanroom itself is scrubbed hundreds of times per hour.Once up and running, Dr.Semiconductor used a particle detector to measure 40 particles per cubic foot (am I allowed to say, as a Brit, it's a bit brain boggling that this kind of thing is being measured in old "customary" units...?), putting the backyard "lab" in the Class 100 cleanroom category, the same as used by TSMC, Intel Samsung and so on. Very impressive.So, backyard chipmaking it is? Maybe not. After building the cleanroom, you'll need to conjure your own chip-making tools, too. And if you can't do that, which to cut a long story short, is going to be a rather harder job, you'll need a mere few hundred million dollars for the latest ASML lithography machine.And hundreds of millions more in digital design tools, some e-beam writers and plasma etchers to make your lithography masks, an ion doping implanter and an atomic layer deposition tool or three, and a mini packing plant, to mention but a small fraction of the hardware involved.

Normally, it costs upwards of tens of billions of dollars to build a cutting-edge fab. But that's obviously with an eye to big production volumes. For we mere DIYers hoping to knock out a few homebrew chips for us and our friends, maybe it would be possible to keep that to single-digit billions. Bargain.On second thought, maybe we're just going to have to wait the whole AI-bubble-chip-supply-crisis thing out. And wait, I forgot. Despite all that cost, when it comes to CPUs and GPUs especially, as opposed to memory, we haven't even got any chip designs to hand. That's merely yet another very expensive problem when it comes to GPUs.But with CPUs, at least for gaming, the AMD-Intel monopoly on x86 rights means you couldn't legally make one even if you somehow had all the equipment and knowledge to do so.