Three-dimensional projection mask-less patterning (PMLP) of micro-lenses and cones: Monitoring and modelling of ion multi-beam kinetic sputtering in GaAs

A projection mask-less patterning (PMLP) proof-of-concept tool, realised as part of the European FP6-NMP integrated project CHARPAN (Charged Particle Nanotech), has been applied for three-dimensional patterning of a GaAs surface, using a stencil mask with a pre-defined opening distribution. A 10 × 10 matrix of micro-lenses was used as test structure for argon ion multi-beam structuring, while studying the time evolution of the sputtered structures. The kinetic sputtering and re-deposition have been modelled in simulation software, in order to be able to correct for such effects beforehand in the design of datasets to be fed to the future programmable aperture plate.