LIFT-OFF TECHNOLOGY FOR THICK METALLIC MICROSTRUCTURES

1 KRÁTKÝ Stanislav
Co-authors:
1 HORÁČEK Miroslav 1 MELUZÍN Petr 1 KOLAŘÍK Vladimír 1 MATĚJKA Milan 1 OULEHLA Jindřich 2 PEŠIĆ Zoran
Institutions:
1 Institute of Scientific Instruments of the CAS, v. v. i., Brno, Czech Republic
2 Thermo Fisher Scientific, East Grinstead, United Kingdom
Conference:
26th International Conference on Metallurgy and Materials, Hotel Voronez I, Brno, Czech Republic, EU, May 24th - 26th 2017
Proceedings:
Proceedings 26th International Conference on Metallurgy and Materials
Pages:
1298-1302
ISBN:
978-80-87294-79-6
ISSN:
2694-9296
Published:
9th January 2018
Proceedings of the conference were published in Web of Science and Scopus.
Metrics:
27 views / 14 downloads
Abstract

This paper deals with a method enabling the preparation of thick metallic microstructures on metal substrates. Such metallic microstructures can be used as a resolution samples to characterize various microanalysis techniques, such as X-ray fluorescence (XRF) or X-ray photoelectron spectroscopy (XPS). Moreover, the patterned samples could be used as anodes to characterize focusing properties of X-ray tubes for micro CT systems. Considering that the standard lift-off technique is designated for structures with the thickness of several hundred nanometers at most, we had to modify lift-off technique to be possible to use it for preparation of very thick metal layers (several microns) with spatial resolution of a few microns. The mask with the desired pattern for UV exposure was prepared by e-beam lithography. SU-8 photoresist was used for a lift-off because of its aspect ratio ability, process purity and high resistance to heating. We used a thin layer of PMMA under the SU-8 masking layer to guarantee the photoresist would lift-off correctly. Thick aluminum layer was deposited by thermal evaporation. The dependence of metal layer thickness as a function of required exposed line width was determined. The final lift-off process was carried out in acetone ultrasonic bath. Generally, this technology can be used for the evaporate deposition of various materials with several microns thick layer in micron resolution.

Keywords: Lift-off technique, SU-8 photoresist, e-beam lithography, thick layer evaporation.
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