■ X-ray mask fabrication

At first an X-ray mask is made with resist drawn with e-beam or laser, followed by gold electroplating as X-ray absorber. For high contrast structures, an additional high contrast mask is required.

■ X-ray lithography (Lithographie)
Precision structures drawn on the X-ray mask above are copied on the resist on the substrate. Thanks to parallel X-ray beam provided by the synchrotron radiation facility KARA (formerly ANKA), high aspect ratio with smooth side walls are realised.

■ Electroplating (Galvanoformung)
Metal parts with high precision structures with a high aspect ratio are realised with electroplating done between the precision resist gaps made with X-ray lithography.

■ Polymer moulding (Abformung)
To copy the precision structures on polymer substrates, mould inserts for injection moulding and hot-embossing could be made using the process above. This allows for realising precisely replicated micro polymer structures.

■ High contrast resolution targets for X-ray imaging
With a minimum line width of 0.3 µm and a thickness of more than 3.0 µm in gold, the targets will surely contribute to the improvement of imaging qualities of indsurtrial X-ray detection systems.
Details in Press release

■ X-ray gratings for Talbot interferometry
High aspect ratio absorption gratings, narrow period phase gratings / absorption gratings for a multi-modal X-ray contrast imaging method called the Talbot interferometer.
Link to X-ray gratings

■ High aspect ratio polymer structures
Polymer mould structures to be electroplated to make X-ray gratings for Talbot interferometry made of gold.
Top: For one dimensional X-ray grating
Bottom: For two dimensional X-ray grating
Both with a period of 10 µm, thickness of 200 µm, aspect ratio of 40.

■ X-ray focusing Compound refractive lens, CRL
Compound refractive lenses (CRLs) used at e.g. SPring-8 to focus monochromatic hard X-ray down to a submicron focus spot size.
Link to X-ray lenses

■ Micro through-holes (X-ray apertures)
(a) Multi holes / X-ray multi-collimator
Multiple through-holes with a diameter of e.g. 3.0 µm on gold membrane (thickness 80 µm). Application: X-ray multi-collimator for space science.

(b) Single through-hole (X-ray aperture)
High aspect ratio through-hole with a diameter of 5 µm in the centre of 200 µm thick gold plate.
Application: X-ray aperture at a synchrotron radiation beam line

■ Micro gears 1
Application: watch gears
Micro metal structures made with X-ray lithography followed by electroplating. High precision aperture structures in gold and Nickel.

Scale bar (yellow line): 1 mm

■ Micro gears 2

■ High aspect ratio through-holes in nickel

Application: Apertures for hyperspectral camera
- 2.5 µm gap, structure depth 180 µm
- Reduction of keystone and smile

Reference: A Fridman et al. "Measurements of the performance of the light mixing chambers in the mixel camera", Optics Express 23(10):13659, 2015

■ X-ray test apertures

Application: Knife edge measurement of synchrotron X-ray beam
Structures: Gold membrane of 30 µm thickness with various square apertures (5 to 1,000 µm side lengths)