Picture of the Month - August 2019
Here you see current insights into the research of the LaMa groups. A collection of the former pictures can be found in the Gallery.
Test series for parameter optimization of 3D microlithography in SU-8
Since January 2019, the Micro and Nanostructuring Laboratory has been equipped with a device for three-dimensional micro and nanolithography based on two-photon lithography (Photonics Professional GT from Nanoscribe in Eggenstein-Leopoldshafen). In two-photon lithography, a laser beam whose photon energy is not sufficient to expose a photoresist is focused by microscope optics. Around the focal point, in a volume element (voxel) which is smaller than the wavelength of the light in the lateral direction and in the vertical direction in the region of a micrometer, such a high intensity is produced that two-photon absorption takes place and the photoresist is exposed. This voxel is scanned in three dimensions by the photoresist. After processing (in the case of a "negative" resist) the exposed structure remains.
Scanning electron micrography shows a series of tests of volcanic emitters produced on a silicon substrate from the negative resist SU-8 in order to determine those parameters which represent an optimum compromise between the quality of the structure produced on the one hand and a reasonable writing time on the other. Such volcanic emitters are of interest as core components of future miniaturized electric space propulsion systems based on the electrospray effect.
The Photonics Professional GT is accessible within the MiNaLab method platform of the ZfM/LaMa, interested parties are welcome to contact MiLaLab@lama.uni-giessen.de at any time.
This picture was submitted by Nathalie N. Weigand (Apprentice as Microtechnologist at ZfM/LaMa).