https://blog.robertelder.org/how-to-make-a-cpu/ Robert Elder Software Inc. * Home * Store * Blog * Contact * Home * Store * Blog * Contact * #linux * | * #commandline * | * #softwareengineering * | * #compilers * | * #embeddedsystems * ... * View All >> How To Make A CPU - A Simple Picture Based Explanation 2021-11-09 - By Robert Elder The purpose of this article is to explain how to make a CPU out of rocks and sand as fast as possible without using too many words. As the world of proprietary hardware and software crushes in around us, we risk losing the ability to make things for ourselves as individuals. It is for this reason that I felt compelled to learn how one could hypothetically make their own integrated circuits by themself. Skip to the end of this article for a few more words on this subject and a disclaimer. 1) Get a rock. Quartz Rock 2) Smash the rock. Smash The Rock 3) Now you have 98% concentrated silicon dioxide. Purify it to 99.9% pure silicon dioxide. 98% SiO2 98.9% 4) Purify it further to 99.9999999% polysilicon metal. Polysilicon 5) Put the polysilicon ingots into a crucible. Polysilicon In Crucible 6) Heat the silicon ingots to 1698 degK. WARNING: do not attempt melting silicon at 1698 degK in your kitchen home oven. Head The Polysilicon 7) Take a small seed monocrystal and dip it into the vat of molten silicon. WARNING: do not place your hands in molten silicon. Seed Monocrystal 8) Slowly pull the crystal out as it cools. Further reading: Boule, Czochralski Method. Pull Out Monocrystal 9) Now, you've got a monocrystal of pure silicon. Cut it into thin slices. Silicon Monocrystal Silicon Monocrystal Top Cut Monocrystal 10) Now, you've got pristine freshly-cut silicon wafers. Optionally, dope them with Boron, Phosphorus or another dopant. Freshly Cut Wafer Boron Phosphorus I was not brave enough to buy elemental phosphorus, so you'll have to use your imagination with the matches. 11) Put photoresist on the wafer. Photoresist 12) Take a chromium-etched photo-lithographic quartz mask with your desired circuit pattern and shine a laser beam through it to project the circuit pattern onto the wafer. Shine Light Photomask Photomask 13) The locations of the shadows produced by the photo-mask will control where the photo-resist is chemically changed on the surface of the silicon wafer (depending on whether you used positive or negative photoresist). Photomask Shadows 14) Now, develop the photoresist. Develop Photoresist 15) Acid etch the exposed parts of the wafer. Acid Etch Wafer 16) Perform countless iterations and repetitions of homo-epitaxy, hetero-epitaxy, pseudo-epitaxy, diffusion doping, copper interconnect layers, chemical mechanical polishing, photoresist applications, acid etching, and photomask exposing to build up the desired features on the wafer. Silicon Wafer Features Chemical Mechanical Polishing 17) Now you've got a finished silicon wafer. Cut it into pieces. Finished Silicon Wafer Closeup Cut Silicon Wafer 18) Now you've got un-packaged silicon dies. Locate the pads on the silicon chip, and attach bond wires, or use the flip-chip method as is done now for most modern processors. Unpackaged Silicon Dies [18-locate-bond-points_600x338_q70] 19) Use the bond wires or solder balls to provide an electrical connection between the pins on the chip package, and the pads on the silicon die. Bond Wires And Pins Bond Wire Closeup And that's how you make a CPU. Also, see CPUs Are Smaller Than You Think for a look inside a real Intel CPU. A Few More Words Obviously, the process of making a modern CPU is more complicated and less well-defined that depicted by this article. Every new generation of chips usually makes changes to the way features are built up on the wafer (not just in terms of feature size). Many common techniques are not even mentioned in this article, and many important steps have been left out. Important details (such as precise chemical compositions/concentrations) are extremely proprietary and you won't see anyone describing them on HackerNews or Reddit. Many steps in the process (such as sourcing and purification of the silicon) have more than one commonly used method. If you want to learn more about these topics, the right search phrases are "Advanced Optics For Photolithography" and "Chemical Deposition Nanofabrication" or "Lithographic Metrology". Although this article isn't perfect, the hope is that an interested reader will benefit from using many of the topics discussed herein as search terms for further research on their own. While cutting-edge nanometer scale features are not likely to be accessible for a hobbyist, micron-scale amateur chip fabrication does appear to be quite feasible. I have not tried this myself, but Sam Zeloof has, and you should definitely check out his YouTube channel. I think you could probably even build some basic chips with far less equipment than he has if you get the optics right. You could probably make it a hobby business selling cusom chips to other tech people! A Word Of Caution: In case it wasn't already clear, I don't advise that anyone actually attempt making integrated circuits in their apartment in the manner shown in this video. The 'photoresist' and 'developer solution' in this video is just a colored prop. The real chemicals are usually hazardous and you should only work with them with proper safety gear in a well ventilated area or in a fume hood. Example Uses Of What Causes CPUs Are Smaller Semiconductors - Microchip Silicon Bit Flips In Than You Think More Than Just Dies - Random Sample Computer CPUs Are Smaller CPUs of 5 Different Chips Memory? Than You Think Example Uses Of $25.00 CAD What Causes Published Semiconductors - Microchip Silicon Bit Flips In 2021-11-09 More Than Just Dies - Random Sample Computer CPUs of 5 Different Chips Memory? Published Published 2022-03-03 2023-02-08 Die Photos Of Imaging A Hard Drive Jeri Can You Create A Saifun With non-ECC Memory Ellsworth & Wireless Bridge SM90USLC2GbA - What Could Go the Robot With ESP8266 Flash Memory Wrong? Uprising of Modules? Die Photos Of Imaging A Hard Drive 2038 Can You Create A Saifun With non-ECC Memory Jeri Wireless Bridge SM90USLC2GbA - What Could Go Ellsworth & With ESP8266 Flash Memory Wrong? the Robot Modules? 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