Microneedle-based electrodes with integrated through-silicon via for biopotential recording

The fabrication of a novel ultrasharp silicon microneedle array for use as a physiological signal monitoring electrode is described. This work uses double-sided silicon wafer patterning and anisotropic potassium hydroxide wet etching to simultaneously create a microneedle on the front side of the wafer, and a through-silicon via from the backside. Metal deposition on both the front and the back of the wafer then establishes electrical contact through this via between both sides of the electrode. This technique eliminates the limitations associated with other approaches that are used to create front-to-back electrical contact and that may be slow or cumbersome. Wearable electrode prototypes have been assembled using these arrays, and electrocardiography (ECG) and electromyography (EMG) recordings have been carried out to verify the functionality of the technique.