Ultrananocrystalline diamond-CMOS device integration route for high acuity retinal prostheses

Area of Science:

• Biomedical Engineering
• Materials Science
• Neuroscience

Background:

• High-density electrodes are crucial for advanced biomedical implants.
• Increasing electrode count and density can improve vision in retinal prosthesis users.

Purpose of the Study:

• To present an integration strategy for diamond-based, high-density stimulating electrode arrays with a custom application-specific integrated circuit (ASIC).
• To demonstrate a method for enhancing vision restoration through improved retinal prostheses.

Main Methods:

• Utilized flip-chip bonding with indium bumps for high-density vertical interconnects between the ASIC and diamond electrodes.
• Employed polydimethylsiloxane (PDMS) for biocompatible housing, preventing contamination.
• Applied micro-imprint lithography for precise patterning of indium bumps on non-coplanar substrates, ensuring compatibility with silicon ASIC and aluminum pads.

Main Results:

• Successfully integrated a 256-electrode diamond array with a 150 μm pitch.
• Demonstrated the feasibility of indium bump bonding for high-count, high-density interconnects.
• Validated the strategy for scalability to tens of thousands of electrodes with a 10 μm pitch.

Conclusions:

• The developed integration strategy is suitable for high-acuity retinal prostheses.
• This approach holds significant potential for future bionic implants requiring high-density neural interfaces.
• The technology enables enhanced vision restoration for patients with retinal implants.