Performance evaluation of direct laser lithography system for rotationally symmetric diffractive optical elements

We have developed a direct laser lithography system for fabrication of precision diffractive optical elements such as Fresnel zone plates and computer-generated holograms. The developed lithography system has possible working area up to 360 mm and minimum linewidth of 0.5 mu m. To assure the performance of the lithography system, the performance evaluation was carried out on the moving stages, the writing head module, and the light source, respectively. In this paper, we report the performance evaluation including the standard uncertainties of each part, the combined standard uncertainty, and finally the expanded uncertainty to give a particular level of confidence.