A meniscus morphology modulation method for meniscus-confined electrodeposition

Meniscus-confined electrodeposition (MCED) is an emerging micro-nano-fabrication method. It has attracted much attention due to its low cost, simple process and ability to freely fabricate complex three-dimensional structures with high aspect ratios. However, in the MCED process, the meniscus morphology (confined electrochemical reaction micro-region) is susceptible to the interference of external factors (environmental humidity and variation in the distance between the probe tip and the deposited microstructure), thereby affecting the deposition continuity and stability. To address this challenge, we developed a meniscus morphology regulation method that controls the pressure inside glass probes through tail-end pressurization to adjust the radius of meniscus profile. Simulation and experimental results show that by adjusting the solution pressure (ranging from -5 kPa to 5 kPa), the meniscus width can be controlled within 0.6 to 1.5 times its initial value (the width under no applied pressure). The most notable achievement is that a copper pillar array with a height of 33 μm and a width ranging from 7 to 15 μm is successfully fabricated by adjusting the diameter of the meniscus profile during the deposition process. The results show that the proposed method not only improves the continuity and stability of electrochemical deposition, but also provides a new idea for the preparation of complex three-dimensional structures, which effectively expands the application scenarios of MCED.