I was reading as article about the latest 5 nanometer IC technology that state of the art production facilities are using. Particularly TSMC in Taiwan. What struck me is that 5 nm wavelength isn't far above xray. In the uv spectral range there is enough energy to excite valence shell (outer) electron in atoms. These are the electrons involved in chemical bonding between atoms. At say 0.1 nm we are in the x-ray region where there begins to be enough energy to excite transitions between energy levels of inner, or kernal, electrons in atoms. What's truly amazing is that 5nm light is capable of producing I.C. traces 15,000 times smaller than the diameter of a typical human hair, according to the article I read, (I didn't check that calculation). To give you an idea of how short this wavelength is, consider that chemical bonds are typically 1 to a few Angstroms. 1 nm is 10 Angstroms , so 5 nm is ~ 50X typical chemical bond lengths. That just seems extraordinary to me. The frequency is up in the million GHz region! This is spectacular technology. Could we go as far as ~1 nm? That would produce, ceteris paribis, chips ~5 times smaller than today's amazing chips!
We hear lots of technological info from US, Taiwan, S. Korea ... but not much from China. Who knows, China is coming up with innovative, out-of-the-world technology.
Most of the equipment which is capable of making these 5 nanometer chips is manufactured by ASML. They explain the basics of their equipment on their website: https://www.asml.com/en/technology/lithography-principles