The 40nm lithography machine is capable of producing 28nm chips.
The lithography machine can achieve a higher process by multiple exposures, and in theory, the 55nm lithography machine can achieve the production of 28nm chips by double exposure. The 40 nanometer lithography machine can produce 28 nanometer chips by double exposure method. For example, SMIC's n1 and n2 technologies are also lithographic processing technologies based on multiple exposures.