This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
This Small Business Innovation Research (SBIR) Phase II project aims to develop an optical-maskless-lithography technology that is capable of high resolution, high throughput, flexibility, low cost, and extendibility. Current lithography technologies suffer from the problems of high tool costs, high mask costs, and inflexibility (in the case of optical-projection lithography), or high tool costs, very low throughputs, and high complexity (in the case of scanning-electron-beam lithography). The emerging Zone-Plate-Array-Lithography (ZPAL) technology and its optical extension to sub-100 nanometers via absorbance-modulation optical lithography (AMOL) will mitigate these issues, while providing unprecedented flexibility in nanopatterning. The proposed project covers three major thrusts: firstly, the manufacture of zone-plate arrays containing over 1000 zone plates, each with a numerical-aperture (NA) greater than 0.85; second, the manufacture of dichromat arrays containing over 1000 zone plates, each with a numerical-aperture (NA) greater than 0.85; and lastly, the design of high-efficiency lenses to overcome many of limitations of conventional zone plates and dichromats.
The broader impact/commercial potential of this project is the creation of a fabrication tool which will enable a new paradigm in the development and manufacture of nanostructures by sharply reducing the development-cycle time and manufacturing costs. At present, the tools that are available for the creation of such nanostructures are highly limited in flexibility, resolution, cost and throughput. Being maskless, this technology provides flexibility by enabling the designers of nanostructures to quickly realize their designs in hardware for prototyping and even low-volume manufacturing. This new tool could potentially benefit a wide spectrum of industries including micro-electro-mechanical devices (MEMs), nano-electro-mechanical devices (NEMs), nano-electronics, nano-magnetics, integrated optics, photonics, biochips, and microfluidics.
The objective of this project was to develop technology for fabricating new classes of lenses, appropriate for nanoscale photolithography, that exhibit properties superior to those of traditional lenses made of glass. The new lenses are called diffractive-optical lenses or Fresnel phase zone plates. There are many advantages, as well as some disadvantages, of such lenses. Advantages include low-cost fabrication, compact size and, most important, the opportunity to implement "wavefront engineering," something that is not feasible with traditional glass lenses. Prior to this project, the disadvantage was low efficiency of focusing. The diffractive-optical lenses of interest consist of planar arrays of concentric rings of dielectric material, numbering on the order of 100, having a total diameter only slightly larger than that of a human hair. Using modern electromagnetic simulation tools, this project proved that by varying the diameter of individual rings, and their cross-sectional structure via nano-scale patterning, the focusing efficiency of the lenses could approach 100%. It was also shown that two distinct optical wavelengths could be simultaneously focused, the shorter into a sharp spot, the longer into a donut form with a central null. These two findings constitute a major intellectual advancement in the fields of optics and photolithography. The broader impact of this project was the validation that with additional development, high-efficiency, high-quality diffractive-optical lenses could be designed and fabricated, and that such lenses would find transformative application in custom nanomanufacturing by being incorporated in a maskless photolithography system under development at the company.
