0.22 nanometers. Silicon atoms are about 0.22 nanometers in diameter. The manufacturing process of mobile phone chips is impossible to exceed 0.22 nanometers. This is also one of its physical limits.
One is the lithography equipment needed to make chips. Lithography uses the frequency of light, which has a physical limit. The frequency of light cannot be required to be infinitely high.
The other is the silicon material needed to make chips. The transistor inside the chip, no matter how small, can not be smaller than the silicon atom, it has a physical limit.
Now the strongest chips in mobile phone chips have been developed to five nanometers, but the limit of silicon chips is two nanometers.