Title. I’ve read recently a bit about chips and wondered how it’s even possible for cutting edge chips, such as those produced my Intel and TSMC to just apply metal vapor to a wafer and know that they will behave like a transistor should.
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You’ve grossly oversimplified the process. A given wafer will go through hundreds or even thousands of steps to produce a working integrated circuit.
The one big thing you’re missing is that all the deposition and etching steps are patterned using an in situ mask (“photoresist”) on the surface of the wafer – protecting some areas from adding/subtracting material, while allowing it to happen in areas where the mask has an opening.
The photoresist is coated on the wafer, then exposed to UV or electron beams in the pattern needed for a given step, then washed to selectively remove resist material either where the exposure occurred (“positive tone”) or where it didn’t (“negative tone”). The wafer is then subjected to an etch or deposition step, then the resist is stripped off in preparation for the next coat/expose/process/strip cycle.
Transistors are made via implanting dopant atoms into the silicon. The metal layers are just wires interconnecting the transistors.
If you spray some spray-paint onto a surface with a stencil on it, the resulting paint pattern on the surface will be the same pattern as the one on the stencil.
Transistors are created by implanting silicon with dopants like Boron and Phosphorus in a very similar way. We create a stencil on the surface of the wafer (using photolithography and other deposition technologies to copy a master stencil onto the wafer) and then ‘spray’ the wafer with Boron/Phosphorus. The resulting pattern of boron/phosphorus that get implanted into the silicon will match the pattern of the stencil. This created the p and n parts of the transistor, and then you use another stencil to create the capacitor part, and then another to create the metal connections.
Hello, im a physicist who’s worked in semiconductor manufacturing for 10 years. The basic problem you are highlighting is: how do we draw really small lines?
Simple terms: light wavelengths are small for UV light. They get smaller for even higher frequency. We also use some tricks like using steppers rather than scanners. You can get even small lines by using high energy electrons.
Its all about finding the right chemical that polymerizes by being exposed to the right frequency of light.
TLDR: it ain’t easy, but we use high energy light to make tiny lines.
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