A non-contact, optical method for fabrication of arrays of nanostructures that is useful for semiconductor-based devices, such as flash memory. The system utilizes a patented EUV laser in combination with a novel demagnification technique to print features on the target that are smaller than those on the mask. A huge advantage is that the printed arrays are virtually free of any defects in the mask due to the optical principles involved (Talbot effect).
The ability to fabricate nanoscale structures in semiconductor materials in a customizable, cost-effective manner is of great benefit to semiconductor and other high-tech companies seeking to further decrease feature size in electronic devices. As feature sizes push into the nanometer scale, conventional methods are constrained by fundamental physical limitations due to the optical wavelengths employed and the presence of defects. Researchers at Colorado State University and the University of Wisconsin, Madison have developed a new optical patterning method for the fabrication of nanometer scale features that nearly completely eliminates any defects present in the mask. The invention, based on the well-known Talbot effect, creates arrays of periodic nanostructures over large areas (approx. 1 mm2 at a time) with very short exposure times (1-2 minutes). Use of a patented extreme ultraviolet (EUV) laser and a novel demagnification technique enable feature sizes on the nanometer scale. Parameters such as exposure time, intervals, and laser power can be varied to suit the photoresist chosen and the needs of the user.A significant advantage of this nanopatterning technique is that it almost completely ignores any defects in the mask. Since each feature printed on the target is an average of the unit cells arrayed on the mask, any defect in a single unit cell on the mask is averaged out and a virtually defect-free image results. Another advantage is that the demagnification technique allows for printing of arrays of nanostructures with dimensions smaller than those of the mask. Both of these advantages have the benefit of relaxing the requirements of the mask: features on the mask need not be as small or as defect-free as the features desired on the target. The present invention should be of benefit to semiconductor companies (such as makers of flash memory devices) seeking to print relatively large arrays of nanometer-scale features with few defects. The technique is scalable, flexible, and non-contact (preserving the life of the mask). It is well-suited to custom arrays as well as large scale printing.Features and Benefits• Non-contact, optical method for fabrication of arrays of nanostructures• Patented EUV laser and novel demagnification technique result in printed features that are smaller than on mask• Virtually error free - defects in the mask are not transferred to the target• Application to semiconductor-based devices, such as flash memory
Other Information: Inventor Information:Mario MarconiLukasz UrbanskiJorge RoccaArtak Isoyan*Francesco Cerrina**University of Wisconsin, MadisonContact:Jeremy Nelson, Ph.D.Director, Licensing & Business Development