@inproceedings{discovery10190389, publisher = {IMAPS - International Microelectronics Assembly and Packaging Society}, booktitle = {IMAPSource Proceedings 2023 (EMPC)}, volume = {2023}, month = {March}, year = {2024}, title = {Initial L ife Test of Silicone E ncapsulated FR 4 Printed Circuit Boards for Pre-Clinical A ctive Implants}, journal = {Advancing Microelectronics}, number = {EMPC}, note = {This version is the author accepted manuscript. For information on re-use, please refer to the publisher's terms and conditions.}, pages = {224--227}, issn = {2222-8748}, keywords = {life test, encapsulation, printed circuit board, impedance, FR4, solder}, url = {http://dx.doi.org/10.4071/001c.94758}, abstract = {Silicone encapsulated FR 4 printed circuit boards may provide a rapid solution for protecting pre-clinical prototype implant electronics. Interdigitated electrodes (IDE s) with and without solder coating were manufactured on Cu-FR 4 laminates and silicone encapsulated (N = 14). IDE s were aged in saline and change in impedance was measured. Solder coated IDE s had stable 1 kHz impedances throughout the aging period with promising lifetimes for pre-clinical prototypes. A single uncoated IDE failed with a fall in impedance and verdigris. Other uncoated IDEs showed increasing impedance and dark copper(II) oxide. Failures attributable to contaminants and moisture ingress are under investigation.}, author = {Ali, I and Xue, F and Henriquez, CP and Niederhoffer, T and Idil, AS and Iang, DJ and Lancashire, HT} }