High-Density Neural Microelectrode Arrays With Complementary Wedge-Shaped 3d Assembly Interfaces For Brain Activity Recording

This paper introduces a high-density neural microelectrode array with a complementary wedge-shaped 3D assembly interface. The design incorporates five 2D neural probe chips, which are bonded to a flexible printed circuit (FPC) using an anisotropic conductive film (ACF) that features a complementary inverted trapezoidal interface. This approach results in a 3D neural microelectrode array consisting of 1280 microelectrodes, achieving both high-density integration and superior conduction efficiency in the 3D assembly. The two-dimensional neural probe chip integrates 256 microelectrodes within a 1.33 mm ² area by making the microelectrodes protrude on the probe surface through a three-layer composite metal structure. The results from electrochemical impedance spectroscopy (EIS) reveal that the complementary wedge-shaped three-dimensional interface achieves exceptional uniformity and 100% conduction efficiency. Furthermore, after applying gold plating to modify the electrode surface, the AC impedance at 1K Hz decreases significantly from 1.58 MΩ to 206 KΩ.