Thin Film Flex Circuits

A process has been developed at the Tyndall to manufacture flexible thin-film microelectrodes in a polymer material using standard techniques from Integrated Circuit processing to create the circuitry on a quartz wafer substrate. The fabricated circuits are then released from the carrier substrate using an excimer laser to ablate the quartz-polyimide interface [1]. This laser release technique has proven successful for films as thin as 3 microns [2]. This project was funded by Fighting Blindness Ireland and the Enterprise Ireland funded D-Systems Project.

Applications: Retinal Prosthesis Implant

It has been proposed that a retinal prosthesis will provide a sensation of vision in a diseased eye by directly stimulating the retinal neurons with a micro-electrode array. Two of the most prevalent diseases falling into this category are Age -related Macular Degeneration (AMD) and Retinitis Pigmentosa (RP). In the United States alone 700,000 new AMD patients are diagnosed each year. The overall incidence of RP is 1 in 4000 live births. Currently, a multi-national effort is underway to develop a retinal prosthesis implant. All aspects of the implant ranging from telemetry through implant fabrication to surgical implantation procedures are being investigated. This project investigates micro-fabrication techniques to fabricate prototype implants with a total thickness of just 16 microns. The prototypes include a range of electrode types, and designs for both epi-retinal and sub-retinal surgical placements. These will allow a range of issues to be studied including for example the influence of electrode design on stimulation efficacy.

Contact: John Alderman. | E-mail: alderman@tyndall.ie

Also: Flexible Substrates for 3-D Integration

[1] N. MacCarthy, T. Wood, H. Ameri, D. O’ Connell, J. Alderman, A laser release method for producing prototype flexible retinal implant devices, Sensors & Actuators: A. Physical , November 2006, 132 (1): 296-301

[2] B. Majeed, K. Delaney, J. Barton, N. MacCarthy, S. C.O'Mathuna, and J. Alderman, Fabrication and Characterization of Flexible Substrates for Use in the Development of Miniaturized Wireless Sensor Network Modules, Journal of Electronic Packaging , September 2006, 128 (3): 236-245