Optical lithography can be extended to 12 nanometers, according to Massachusetts Institute of Technology researchers who have so far demonstrated 25-nm lines using a new technique called scanning beam interference lithography.

Interference lithography uses two lasers of different frequencies that interfere with each other to create a grating image with much higher resolution than is possible with either laser alone. Nevertheless, non-optical limits to interference lithography have limited its use to testing photoresist processes rather than actually imaging circuit patterns on wafers.

By adding scanning to the mix, the MIT researchers believe interference lithography can become commercially viable at the 25-nm node and beyond.