The size used to correspond to minimum feature size. A transistor consists of multiple features and used to be fairly planar with things arranged side by side m

The size used to correspond to minimum feature size. A transistor consists of multiple features and used to be fairly planar with things arranged side by side more or less. As it became harder to shrink the minimum feature size, they figured out other ways to shrink. For example various ways of stacking things on top of each other rather than having them side by side[1]. As such they could cram more transistors in the same area compared to a planar transistor, and hence you got the same effect as shrinking the minumum feature size. Not sure exactly how they name things, but one could calculate what feature size would have been required to get a given transistor density using a plain planar transistor, for comparison. [1]: https://semiengineering.com/from-finfets-to-gate-all-around/ https://semiengineering.com/from-finfets-to-gate-all-around/