Conductive microtip electrode array with variable aspect ratio using combination process of reactive ion etching

A micromachining process for a conductive microtip electrode array has been developed using a combination process of reactive ion etching. A localized conical ultra-micro electrode (UME) with submicron width is realized on the tip end for electrochemical measurements. A height of several tens of microns of the silicon microtip is achieved, and the area beyond the UME is covered with dielectric material for electrical insulation. A high-aspect-ratio silicon microtip is fabricated using anisotropic and isotropic etching with varying the gap and diameter of the etch masks. Cyclic voltammetry is conducted to characterize the electrochemical properties of the UMEs. The results indicate that the electrical connection on the UME works successfully, and the measured peak currents were found to be in good agreement with the values estimated from analysis based on conical UME theory. (paper)