Misha Dubrovsky
2016 Hackaday Prize - Design your concept
This project is a single step toward a huge goal - a self-replicating machine. Others have already taken on the challenge of self-replicating the mechanical hardware of a 3D printer, I will take one small step at a time toward replicating the electronics.
How can a 3D Printer Replicate its own Electronics?
If MetalicaRap does good on its promise to build an electron beam additive manufacturing 3D printer, that printer will have a high vacuum in its main build volume. It will also have the correct optics to guide a beam of electrons onto a tiny spot. If it can do that, it can also guide a beam of ions onto a small spot. By placing a blank silicon die in the build area of MetalicaRap, the focused ion beam can selectively n- or p-dope silicon and create the fundamental building blocks of integrated circuits - transistors, diodes, capacitors, resistors, and more. Metallization layers can similarly be deposited in the vacuum chamber.
Then why does a semiconductor fab cost so much money?
Because it uses photolithography to manufacture a lot of chips fast and simultaneously. Photolithography is an extremely delicate and high-initial cost process. Modern semiconductor fabs also try to make transistors on the smallest possible scales to pack as much into a chip as possible, which greatly increases costs and engineering requirements.
Can you really make semiconductors at home?
Jeri Ellsworth already did it (despite everyone telling her it was impossible), and I replicated her results a few years ago. She made her masks by hand and used diffusion doping, which means that her transistors were too big and inconsistent to make an integrated circuit. With ion implantation, there problems are reduced.
So what exactly are you making?
The specific goal of this project is to demonstrate ion implantation using standard scientific equipment, and then going backward and seeing if there is any way to simply or improvise some of the equipment so that it can be printed using electron beam additive manufacturing, and so that the process can take place at higher pressures. In the future, my design can be incorporated into MetalicaRap so that it can replicate its own circuits.
Another challenge that I will explore is how much can 3D printer microcircuitry be simplified so that it can be printed at larger (and therefore more reliable) scales.
Why did you wait so long to do this?
What enabled this project to go forward was acquiring a QSTAR XL tandem mass spectrometer, which has many of the parts needed for an ion implantation design.
ProgressTH
Looks like a Leybold TW700 series pump? The turbo pump does not need an arduino to run it. Most drives have a standard switch input for on/off. Just supply power and close the switch. You can spin the pump up at atmosphere to verify it starts, you only need to run it a few seconds to verify. Newer pumps will time out when the controller sees the pump cant reach a certain speed after a certain amount of time.
Usually old turbos out of mass specs will run, they never see a dirty environment like a lot of pumps that come out of semiconductor manufacturing equipment. Those can have some really nasty residue in them.
Be very careful with turbos. There is a huge amount of kinetic energy in a pump this size when at speed. If you open the chamber to atmosphere while running very bad things will happen. Even a short burst of pressure from something like air trapped between two valves can be enough to do damage.