High‐Density Flexible Neural Implants with Submicron Feedline Resolution

Advanced Electronic Materials, vol. 11

Abstract

Abstract The development of high‐density microelectrode arrays (MEAs) for large‐scale brain recordings requires neural probes with reduced footprints to minimize tissue damage. One way to achieve this is by implementing dense electrode arrays with narrower feedline dimensions, though this increases susceptibility to capacitive coupling between electrical interconnects. To address this, this study explores the resolution limits for high‐density flexible MEAs by optimizing the fabrication using optical contact lithography (OCL) and electron beam lithography (EBL). OCL enables metal feedlines with widths of 520 nm and interconnect spaces of 280 nm, while EBL allows the realization of 50 nm feedlines with 150 nm spaces on flexible parylene C substrates. Based on these techniques, we fabricate a flexible 64‐channel intracortical implant with a miniaturized cross‐section of only 50 × 6 or 70 × 6 µm 2 . In vivo validation in awake rats demonstrates that the fabricated, high‐density flexible intracortical implants with submicron feedline resolution offer low‐impedance electrodes and reduced crosstalk, enabling reliable neuronal recordings. These findings demonstrate the feasibility of miniaturizing flexible MEAs using a single‐metal layer process, thereby reducing manufacturing complexity in high‐density thin‐film polymer‐based neural interfaces.

Authors 10

1. Lina Koschinski Aachen

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Bioelectronics Institute of Biological Information Processing‐3 Forschungszentrum Jülich 52428 Jülich Germany

   Helmholtz Nano Facility (HNF) Forschungszentrum Jülich 52428 Jülich Germany

   RWTH Aachen University 52062 Aachen Germany

2. Thomas Grap

   Forschungszentrum Jülich

   Affiliation as printed

   Helmholtz Nano Facility (HNF) Forschungszentrum Jülich 52428 Jülich Germany

3. Erkan Yılmaz

   Forschungszentrum Jülich

   Affiliation as printed

   Bioelectronics Institute of Biological Information Processing‐3 Forschungszentrum Jülich 52428 Jülich Germany

4. Marius Kleutgens Aachen

   Forschungszentrum Jülich · FH Aachen

   Affiliation as printed

   Bioelectronics Institute of Biological Information Processing‐3 Forschungszentrum Jülich 52428 Jülich Germany

   FH Aachen University of Applied Sciences 52066 Jülich Germany

5. Simon Decke Aachen

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Bioelectronics Institute of Biological Information Processing‐3 Forschungszentrum Jülich 52428 Jülich Germany

   RWTH Aachen University 52062 Aachen Germany

6. Martin Kasavetov

   Forschungszentrum Jülich

   Affiliation as printed

   Bioelectronics Institute of Biological Information Processing‐3 Forschungszentrum Jülich 52428 Jülich Germany

7. Marie Jung Aachen

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Bioelectronics Institute of Biological Information Processing‐3 Forschungszentrum Jülich 52428 Jülich Germany

   RWTH Aachen University 52062 Aachen Germany

8. Alejandro Carnicer‐Lombarte

   University of Cambridge

   Affiliation as printed

   Bioelectronics Laboratory University of Cambridge CB3 0FA Cambridge UK

9. George G. Malliaras

   University of Cambridge

   Affiliation as printed

   Bioelectronics Laboratory University of Cambridge CB3 0FA Cambridge UK

10. Viviana Rincón Montes corresponding

    Forschungszentrum Jülich · University of Cambridge

    Affiliation as printed

    Bioelectronics Institute of Biological Information Processing‐3 Forschungszentrum Jülich 52428 Jülich Germany

    Bioelectronics Laboratory University of Cambridge CB3 0FA Cambridge UK