The wavelength of light required for a 3-nanometer chip is not 3 nanometers, but shorter ultraviolet wavelengths, generally around 100 nanometers. This is because the resolution of optical technology improves as wavelengths shorten, so shorter wavelengths are needed to ensure that high-precision chips are made.
At the same time, the manufacture of high-precision chips also requires the use of more advanced lithography technology and equipment, which also increases the cost and difficulty of manufacturing. Therefore, the wavelength of light needed to make a 3-nanometer chip is much longer than the chip itself.