1 July 2011 Fabrication of five-layer three-dimensional miniature SU-8 axial fans using ultraviolet lithography
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J. of Micro/Nanolithography, MEMS, and MOEMS, 10(3), 033014 (2011). doi:10.1117/1.3625606
As miniaturization technologies have improved for the past few decades, electronic devices are becoming smaller and the technology needed to fabricate complex three-dimensional (3D) microstructures becomes important. Photolithography is a relatively simple and low-cost method. However, photolithography is, in general, a fabrication method for planar two-dimensional microstructures. In this study, a technique using photolithography is developed to fabricate three-dimensional blades for axial microfan applications. Fabrication of a five-layer SU-8 microstructure for a miniature axial fan of 5 mm diameter using ultraviolet (UV) lithography is presented. Each SU-8 layer was fabricated with a small shift relative to the previous layer. Hence, 3D SU-8 blades with oblique sections have been successfully fabricated using this relatively simple UV lithography. A multiple resist coating and exposure with a single development stage was employed. It was observed that the exposure time for the second to fifth layers was reduced by a factor of 0.7 as compared to that needed for the first layer. A relatively efficient method for the fabrication of multilayer oblique walls was developed. It is probably the first time that UV lithography is used for creating 3D sloping microstructures.
Hamed Keramati, Jianmin Miao, Weng Kong Chan, "Fabrication of five-layer three-dimensional miniature SU-8 axial fans using ultraviolet lithography," Journal of Micro/Nanolithography, MEMS, and MOEMS 10(3), 033014 (1 July 2011). https://doi.org/10.1117/1.3625606

Ultraviolet radiation

Fluctuations and noise



Semiconducting wafers


Scanning electron microscopy

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