Bi-layer encapsulation of Utah array based nerual interfaces by atomic layer deposited Al2O3 and parylene C

We present a novel coating 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 320 days of soak testing at 37 °C in phosphate buffered solution. Also bi-layer coated fully integrated Utah array based wireless neural interfaces had stable power-up frequency and constant RF signal strength during the 600 days of equivalent soaking time at 37 °C. Bi-layer coated Utah arrays had constant current drawing of about 3 mA during 140 days of soak testing.