High-yield benzocyclobutene(BCB) based neural implants for simultaneous intra- and extracortical recording in rats

Haixin Zhu, Jiping He, B. Kim
The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society  
A unique structure for chronically implantable cortical electrodes based on Benzocyclobutene (BCB) biopolymer was designed to perform intracortical and extracortical neural recording simultaneously in basic neuroscience research using animal models. It was fabricated on Silicon wafer using standard planar CMOS surface microfabrication technique. Dry-etchable BCB was used to insulate the electrode and provide flexibility for micro-motion compliance between brain tissue and skull. This electrode
more » ... ll. This electrode is also designed to ease the handling and implantation during the surgery and to integrate buffer circuits to improve the signal-to-noise ratio. The reliable fabrication process was developed to improve the electrode yield and performance. A 1.5um thick Tungsten layer was sandwiched in the electrode tip to improve the stiffness for easy insertion during the surgery. The fabricated electrodes have two intra-cortical recording sites (20×20um) in the tip penetrating into the cortex and two epidural recording sites (80×80um) on each side wing, providing a 6 channel system. One via (40×40um) was also incorporated in the tip to balance the tip and provide the bio-seeding to improve the implants and neural tissue interaction. The acute surgical testing suggests that this electrode structure can penetrate the pia into the cortical tissue without damaging the electrode.
doi:10.1109/iembs.2004.1404208 pmid:17271265 fatcat:um2w7qhalzc5rjkuvzgnnrtwyu