Multilayer Flexible SU8-Gold Microelectrode Arrays for Wearable Bioelectronics

Wearable health trackers for vital signs monitoring are becoming ever more important especially due to the global coronavirus pandemic (COVID-19) caused by SARS‑CoV‑2 virus which severely affect respiratory system and can cause cardiac manifestations. Particularly, wearable solutions seamlessly monitor heart activity critical facilitate personal preventive remote healthcare, as well allow early diagnosis of dysfunctions. A fundamental enabler bioelectronics is sensing bioelectrode used record surface biopotentials. While a plethora attempts have been reported realize skin-conformal dry electrodes electronic skin patches, oftentimes very aspect electrode i.e., actual electrical interfacing readout circuits without disturbing skin-electrode contact, overlooked. To address this issue, paper reports unique tri-layer, polymer-metal-polymer microelectrode design with sidewall metal coating achieve vertical interconnect accesses (VIAs) contact pads external interfacing. The novel optimized process flow herein allows repeatable fabrication flexible in arrayed format yields exceeding 90%. Functionality microfabricated were demonstrated successful acquisition electrocardiogram lead-I configuration clear detection P-QRS-T complex.