Atomic Layer Deposited Al2O3 and Parylene C Bi-layer Encapsulation for Utah Electrode Array Based Neural Interfaces

ABSTRACTLong-term functionality and stability of neural interfaces with complex geometries is one of the major challenges for chronic clinic applications due to lack of effective encapsulation. We present an encapsulation method that combines atomic layer deposited Al2O3 and Parylene C for encapsulation of biomedical implantable devices, focusing on its application on Utah electrode array based neural interfaces. The alumina and Parylene C bi-layer encapsulated wired Utah electrode array showed relatively stable impedance during the 960 equivalent soaking days at 37 °C in phosphate buffered solution. For the bi-layer coated wireless neural interfaces, the power-up frequency was constantly ∼ 910 MHz and the RF signal strength was stably around -73 dBm during equivalent soaking time of 1044 days at 37 °C (still under soak testing).