Laser-based optical lithography to yield a resolution of 2nm half-pitch lines
Using atomic force microscope (AFM), scanning electron microscope (SEM) and transmission electron microscope (TEM) measurements, Dr. Eugen Pavel, CEO of Storex Technologies and his team have demonstrated that 2nm width lines could be written in novel materials such as fluorescent photosensitive glass-ceramics doped with samarium (Sm), relying on a quantum multi-photon confinement effect.
The researchers focused a 650nm wavelength laser diode beam to write high-density lines (3D patterning) on the novel materials at room temperature far beyond the diffraction limit, a fundamental barrier to the exploitation of optical lithography.
AFM image of a single 2nm line covered by 1.5 nm Au spheres.
This direct laser writing process (without any annealing process) involves quantum nonlinear effects which could enable full-wafer-level nanofabrication at a 2nm resolution, with demonstrated channel depths ranging from 1.5 to 5nm. Storex Technologies has developed a dynamic tester with a xyz piezo stage for controlling the laser at small velocity (200 micron/s) and a rotation disc system for high velocity (over 20m/s). The scope of this research is to increase the density of optical data storage by using the third dimension to store data using nanostructures. For instance, the surface storage density accessible with focused beams of light (without near-field techniques) is roughly 1/λ2, says the paper. With a green light wavelength of 532nm, this should lead to 4 bits μm−2 or more than 4 Gigabytes on each side of a 120mm diameter 1mm thick disk. But by storing data throughout the volume at a density of 1/λ3, the capacity of the same disk could be increased 2000-fold, to 8 Terabytes. Storex Technologies is working on improving the resolution below 2nm and is currently looking at industrializing its process.
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