Improvement of the process of precision fabrication of “square”-type microstructures using photolithography and electrochemistry

Currently microstructured heat exchangers are widely used in heat dissipation systems to increase the cooling intensity of high-power electronic components. They also hold promise for electromechanical sensors and microfluidic chips for laboratory-on-a-chip (LOC). This research aims to address key manufacturing challenges associated with maintaining the characteristic dimensions of microstructures at high aspect ratios. A combined method for fabricating precision metal microstructures is presented on the basis of ultraviolet dry film photolithography with electrochemical deposition from copper and nickel sulfate electrolytes. A comparative analysis of the metal particle deposition rate and the edge effect characteristics during the fabrication of nickel and copper microstructures leading to the fusion of elements into dense dendritic formations is carried out. The influence of the conductive frame shape on the quality, geometry, and uniformity of layer growth on the substrate during horizontal deposition in an electrochemical metallization system is noted. Square-type microstructures with height of 100 ± 5 μm, characteristic size of 180 ± 5 μm, and interelement pitch of 90 ± 5 μm is obtained, while maintaining vertical sidewalls, good adhesion to the substrate, minimization of defects during metal deposition and precise reproducibility of the microstructure geometry. The developed technology ensures the formation of mechanically stable microstructures capable of withstanding extreme hydrodynamic loads.

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