Chowdhury, Fatima NafisaSood, RachitNam, HyungwooLobo, Mary KayChoa, Fow-Sen2019-06-032019-06-032019-05-02Fatima Nafisa Chowdhury, Rachit Sood, Hyungwoo Nam, Mary Kay Lobo, and Fow-Sen Choa "Flexible polyimide based 34-channel electrode arrays for mouse EEG measurement", Proc. SPIE 11020, Smart Biomedical and Physiological Sensor Technology XV, 110200T (2 May 2019); doi: 10.1117/12.2518830; https://doi.org/10.1117/12.2518830https://doi.org/10.1117/12.2518830http://hdl.handle.net/11603/13997SPIE Defense + Commercial Sensing, 2019, Baltimore, Maryland, United StatesElectroencephalogram (EEG) recording is a widely used method to measure electrical activity in the brain. Rodent EEG brain recording not only is noninvasive but also has the advantages to accomplish full brain monitoring, compared with that of the invasive techniques like micro-electrode-arrays. In comparison to other noninvasive recording techniques, EEG is the only technique that can achieve sub-ms scale time resolution, which is essential to obtain causal relationship. In this work, we demonstrated a simple microfabrication process for developing a high-density polyimide-based rodent EEG recording cap. A 34-channel rodent electrode array with a total size of 11mmx8mm, individual electrode diameter 240μm and interconnect wire linewidth 35μm was designed and fabricated. For the fabrication process, we first deposit 350nm SiO2 on a silicon substrate. We then fabricate 6-7μm thick first layer polyimide caps with fingers and contact holes. Gold deposition and then lithography etching of 34 channel contact-electrodes and their interconnects were fabricated in the second step. The third step was to cover metal interconnects with a 10μm thick second layer polyimide, which was fabricated with photolithography before the final film released by HF undercutting etching of SiO2 layer. Then the fabricated EEG cap is interfaced with a commercial 34-channel female connector, which is soldered with 34-line wires. These wires are then connected to an ADC to record the EEG data in computer for post-processing. With polyimide, the EEG cap is biocompatible, and flexible which makes it suitable for good contact with rodent skulls.9 pagesen-USThis item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author. © (2019) Society of Photo-Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.EEGPolyimideMicro-FabricationPhotolithographyEEG Recording capBrain activityBiocompatibleflexible microelectrodeText