While the way cpu work may seem like magic, it's the result of decades of clever engineering. As transistor-the building blocks of any microchip-shrink to microscopic scales.
Transistors are now so impossibly small that manufacturers can not build them using normal methods. While precision lathes and even 3D printers can make incredibly intricate creations, they are usually top-out at micrometer levels of precision (that's about one-thirty-thousandth of an inch) and are not suitable for the nanoscale scales.  Photolithography solves this issue by removing the need to move complicated machinery around very precisely. Instead, it uses light to an image on the chip-like a vintage overhead projector, which can be found in classrooms, but in reverse, scaling the stencil down to the desired precision.
The image is projected onto a silicon wafer, which is machined to very high precision in controlled laboratories, as any single speck of dust on the wafer could be losing on thousands of dollars. The wafer is coated with a material called a photoresist, which responds to the light and is washed away, leaving an etching of the CPU that can be filled with copper or doped to form transistors. The Issues With Nano-Scale Photolithography
It doesn It does not actually work, and nano-scale tech runs into a lot of issues with physics. Transistors are supposed to stop the flow of electricity when they're off, but they're so electroluminescent. This is called quantum tunneling and is a massive problem for silicon engineers.
Defects are another problem. Even photolithography has a cap on its precision. It's analogous to a blurry image from the projector; it's not quite as clear when blown up or shrunk down. Currently, foundries are trying to mitigate this effect by using "extreme" ultraviolet light, a much higher wavelength than humans can perceive, using lasers in a vacuum chamber. But the problem will persist as the size gets smaller.
The problem is that the CPU fails, the core is disabled, and the chip is sold as a lower end part. In fact, most lineups of CPUs are manufactured using the same blueprint, but have cores disabled and sold at a lower price. If the defect hits the cache or another essential component, that chip may have thrown out, resulting in a lower yield and more expensive prices. Newer process nodes, like 7nm and 10nm, want to get higher error rates and want more expensive as a result.
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Packaging it Up
Packaging the CPU for consumer use is more than just putting it in a box with some styrofoam. When a CPU is finished, it's still free, but it can connect to the rest of the system. The "packaging" process refers to the method where the delicate silicon is. 19659008] This process requires a lot of precision, but not as much as the previous steps. The CPU is mounted to a silicon board, and all the pins are connected to the motherboard. Modern CPUs may have thousands of pins, with the high-end AMD thread ripper having 4094 of them.
Since the CPU produces a lot of heat, and should therefore be protected from the front, an "integrated heat spreader" is mounted to the top. This makes contact with the and transfers to a cooler that is mounted on top. For some enthusiasts, these results in people delidding their processors to apply for a premium solution.
Once it's all put together, it can be packaged into actual boxes, ready to hit the shelves and be slotted into your future computer. CPUs are made, check out Wikichip's explanations of lithography processes and microarchitectures.