A conic primitive-based pattern generator for electron-beam lithography of diffractive optical elements

The efficient lithography of diffractive optical elements requires the pattern data to be optimized in terms of size and of the fidelity with which it approximates the design. We describe a hardware and software package that provides direct support for curved patterns, rather than resorting to an approximation by polygons, and that can be implemented to enhance existing electron-beam lithography tools. The method employed allows surfaces bounded by conic sections to be approached to the best possible accuracy, and substantially reduces the pattern file size.