Process node
Beginner
The generation of chipmaking technology a chip is built with. Newer generations pack more tiny switches into the same space.
Novice
A chip factory’s named manufacturing generation, such as “7 nm class”. The number no longer matches any physical size on the chip; it labels a generation with its own density, speed, power, cost and design rules.
Expert
Choosing one fixes the building blocks on offer (the library of basic logic cells and the blocks that can be bought in), wafer and mask cost, defect density and factory capacity. Newer is not always better: older processes are cheaper, better understood, easier for analog circuits and long-life parts, and often the only ones where the needed bought-in blocks already exist.
Explained in Specification (Design Flow).