Lasers Enable Finer Chip Structures, Advance of Moore's Law

Current chip manufacturing relies on photolithography techniques, which can only produce chip features that are larger than the wavelength of the light applied.

A process that is described in the paper "Breaking the Far-Field Diffraction Limit in Optical Nanopatterning via Repeated Photochemical and Electrochemical Transitions in Photochromic Molecules", published in Physical Review Letters, can create complex structures chip structures 1/8 the size of the wavelength of the light used. According to the researchers, an effect called stimulated emission depletion imaging (STED) enabled them to go beyond the current limitations of photolithography. In STED, scientists leverage the fluorescent characteristics of materials to emit light when targeted by a laser beam. By controlling the laser's power, the researchers can affect the strength of light emitted and, if the power falls enough, cause a "dark patch" that is smaller than the wavelength of the laser light itself. These dark patches can be used as masks, which can be applied to a surface.

The MIT researchers believe that their invention could be used to create semiconductors with much finer structures than possible today. There could also be an opportunity to apply this technology in photonic devices, MIT said.