Multilayer Fabrication of Micromolding and Electroforming with the Planarization of Grinding for High-Aspect-Ratio Microelectrodes in Electro-conjugate Fluid (ECF) Micropumps

Abstract

Previously, we described a single layer fabrication combining thick photoresist (KMPR) micromolding and electroforming to fabricate ECF micropumps with triangular prism and slit electrode pairs (TPSEs). However, the fabricated TPSEs have a height limitation due to the limitation of KMPR’s aspect ratio caused by serious swelling and deformation of KMPR micromolds. To solve this problem and realize high-aspect-ratio TPSEs, we propose to utilize the multilayer fabrication instead of the single layer one. After each prior micromolding layer fabrication, the precision surface grinding technique is introduced to achieve the excellent planarization of the KMPR micromolds and electroplated TPSEs between the first layer and the second one. We apply this method to successfully fabricate the 3D-integration ECF micropump (3D-EMP) with TPSEs of 880 µm in height. Also, we validate this method by experimentally investigating and comparing the output performance of ECF micropumps composed of double layer TPSEs and previous single layer ones. The novel MEMS fabrication method combining multilayer micromolding and electroforming with the planarization is promising and applicable to a broad range of high-aspect-ratio metallic microstructures.