The 3nm chip means that the smallest unit of silicon transistor gate width of the chip is 3nm. nm itself is a unit of physical length, and for chips, the nanometerlength of the gate width is used to represent the process of the chip. 3nm chip is the highest process that can manufacture chips at present, but the current yield is not high enough to achieve mass production.
The 3nm chip is the most advanced chip at present, and it has just been produced by TSMC in 2020, which is of strategic significance to the entire information industry and the communications industry