Three-dimensional diffractive micro- and nano-optical elements fabricated by electron-beam lithography

The broad development of the micro- and nano-technologies in the past few years increased the need of techniques capable of fabricating sub-micron structures with arbitrary surface profiles. Out of the several fabrication approaches (HEBS lithography, laser writing, etc.) the electron beam writing stands out as the one capable of the highest resolution, superior alignment accuracy and very small surface roughness. These characteristics make the technique greatly applicable in the fields of photonics and micro-opto-electro-mechanical-systems (MOEMS). Here we describe the specificity of fabricating 3D diffractive micro- and nano-optical elements using Leica EBPG 5000+ electron beam system. Parameters like speed of writing, dose accumulation, pattern writing specifics, etc. affect greatly the electron-beam resist properties and the desired 3D profile. We present data that can be used to better understand the different dependencies and therefore achieve better profile and surface roughness management. The results can be useful in future developments in the areas of integrated photonic circuits and MOEMS