Fabrication of hollow microtip electrode array with variable diameter using self-aligned etching process

摘要

In this paper, we propose the fabrication of a hollow microtip electrode array with variable diameter. The intended application of the fabricated electrode is the perfusion or aspiration at the localized area of a biological sample in a microfluidic system. The conductive electrode covered with an insulating layer formed the hollow microtip structure. The lower diameter and height of the fabricated hollow microtip electrode array were measured as approximately 4 and 35 mu m, respectively. A fabrication process for controlling the hollow diameter is proposed based on the self-aligned etching process of the sharp silicon microtip array without an additional photolithography mask. The silicon microtip was exposed only at the tip end by using the self-aligned etching process after coating the conductive and insulating layer. The area of the exposed silicon tip could be controlled by varying the self-aligned etching time, which determined the hollow dimeter after removing the silicon structure. The hollow diameter was adjusted from 0.94 to 2.82 mu m depending on the self-aligned etching time. Moreover, the proposed hollow microtip electrode array was characterized as the electrode to be used in electrochemical reaction measurements using cyclic voltammetry. Additionally, the perfusion of the fluid was demonstrated through the hollow microtip electrode assembled with a microfluidic channel.