Today's chips are silicon-based chips, silicon is the material of the chip, if you still use silicon as a chip, 3 nanometers is likely to be the limit. In addition to silicon, it is possible that carbon-based chips could break the three-nanometer limit, but for now this is only a conjecture.
Chip nanotechnology refers to the use of nanotechnology to shrink the chip manufacturing process, so that more transistors can be crammed into a smaller chip to increase the efficiency of the processor. Nanotechnology can reduce the size of the chip, but also help reduce power consumption to meet the needs of thin and light.