MEMS micro-coils for magnetic neurostimulation
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MEMS micro-coils for magnetic neurostimulation. / Liu, Xiyuan; Whalen, Andrew J.; Ryu, Sang Baek; Lee, Seung Woo; Fried, Shelley I.; Kim, Kayeon; Cai, Changsi; Lauritzen, Martin; Bertram, Nicolas; Chang, Bingdong; Yu, Tianbo; Han, Anpan.
In: Biosensors and Bioelectronics, Vol. 227, 115143, 2023.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - MEMS micro-coils for magnetic neurostimulation
AU - Liu, Xiyuan
AU - Whalen, Andrew J.
AU - Ryu, Sang Baek
AU - Lee, Seung Woo
AU - Fried, Shelley I.
AU - Kim, Kayeon
AU - Cai, Changsi
AU - Lauritzen, Martin
AU - Bertram, Nicolas
AU - Chang, Bingdong
AU - Yu, Tianbo
AU - Han, Anpan
N1 - Publisher Copyright: © 2023 The Authors
PY - 2023
Y1 - 2023
N2 - Micro-coil magnetic stimulation of brain tissue presents new challenges for MEMS micro-coil probe fabrication. The main challenges are threefold; (i) low coil resistance for high power efficiency, (ii) low leak current from the probe into the in vitro experimental set-up, (iii) adaptive MEMS process technology because of the dynamic research area, which requires agile design changes. Taking on these challenges, we present a MEMS fabrication process that has three main features; (i) multilayer resist lift-off process to pattern up to 1800-nm-thick metal films, and special care is taken to obtain high conductivity thin-films by physical vapor deposition, and (ii) all micro-coil Al wires are encapsulated in at least 200 nm of ALD alumina and 6-μm-thick parylene C such the leak resistance is high (>210 GΩ), (iii) combining a multi-step DRIE process and maskless photolithography for adaptive design and device fabrication. The entire process requires four lithography steps. Because we avoided SOI wafers and lithography mask fabrication, the design-to-device time is shortened significantly. The resulting probes are 4-mm-long, 60-μm-thick, and down to 150 μm-wide. Selected MEMS coil devices were validated in vivo using mice and compared to previous work.
AB - Micro-coil magnetic stimulation of brain tissue presents new challenges for MEMS micro-coil probe fabrication. The main challenges are threefold; (i) low coil resistance for high power efficiency, (ii) low leak current from the probe into the in vitro experimental set-up, (iii) adaptive MEMS process technology because of the dynamic research area, which requires agile design changes. Taking on these challenges, we present a MEMS fabrication process that has three main features; (i) multilayer resist lift-off process to pattern up to 1800-nm-thick metal films, and special care is taken to obtain high conductivity thin-films by physical vapor deposition, and (ii) all micro-coil Al wires are encapsulated in at least 200 nm of ALD alumina and 6-μm-thick parylene C such the leak resistance is high (>210 GΩ), (iii) combining a multi-step DRIE process and maskless photolithography for adaptive design and device fabrication. The entire process requires four lithography steps. Because we avoided SOI wafers and lithography mask fabrication, the design-to-device time is shortened significantly. The resulting probes are 4-mm-long, 60-μm-thick, and down to 150 μm-wide. Selected MEMS coil devices were validated in vivo using mice and compared to previous work.
KW - Brain machine interfaces
KW - MEMS micro-coils
KW - Micro magnetic stimulation
KW - Neurochip
KW - Neuroprobes
KW - Neurotechnologies
U2 - 10.1016/j.bios.2023.115143
DO - 10.1016/j.bios.2023.115143
M3 - Journal article
C2 - 36805270
AN - SCOPUS:85148547620
VL - 227
JO - Biosensors and Bioelectronics
JF - Biosensors and Bioelectronics
SN - 0956-5663
M1 - 115143
ER -
ID: 337976186