Abstract
Sensitivity improvement is a challenging issue in miniature pressure sensors. To improve sensitivity and linearity of the device, a wide micro beam structure has been proposed to gauge capacitance changes caused by the applied pressure in a capacitive MEMS fingerprint sensor. Bending behavior of the device and the effect of the protrusion geometry on partial loading of the micro beam has been analytically investigated. Based on the idea of efficient loading of the wide micro beam, an improved design for the capacitive fingerprint sensor is developed to increase sensitivity. It is shown with FEM simulations that the micro wide beam design is superior to the common membrane based MEMS fingerprint sensors in terms of sensitivity and linearity.
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Charlot B, Parrain F, Galy N, Basrour S, Courtois B (2004) A sweeping mode integrated fingerprint sensor with 256 tactile microbeams. J Microelectromech Syst 13:636–644. doi:10.1109/JMEMS.2004.832195
Fojimori T, Hanaoka Y, Fujisaki K, Yokoyama N, Fukuda H (2005) Fully CMOS compatible on-LSI capacitive pressure sensor fabricated using standard back-end-of- line processes. Proc 13th int conf on solid-state sensors, actuators and microsystems Seoul, Korea 37–40. doi:10.1109/SENSOR.2005.1496353
Ganji BA, Majlis BY (2006) The effect of design parameters on static and dynamic behaviors of the MEMS microphone. Proc semiconductor electronics ICSE ‘06 IEEE int conf on 35–40. doi:10.1109/SMELEC.2006.381015
International Biometric Group (2007) Biometrics market and industry report 2007–2012. New York
Knapp AG (2004) Pressure type fingerprint sensor fabrication method. US patent 6,759,264B2 5,325,442
Meleshko VV (2003) Selected topics in the history of the two-dimensional biharmonic problem. Appl Mech Rev 56:33–85. doi:10.1115/1.1521166
Nabipoor M, Majlis BY (2004) A passive telemetry LC pressure sensor optimized for TPMS. Proc semiconductor electronics ICSE’04 IEEE int conf on 345–349. doi:10.1109/SMELEC.2004.1620902
NEXUS (2005) The NEXUS MST/MEMS market analysis III 2005–2009. European Microsystems Network, Neuchâtel
Sato N, Machida K, Morimura H, Shigematsu S, Kudou K, Yano M, Kyuragi H (2003) MEMS fingerprint sensor immune to various finger surface conditions. IEEE Trans Electron Devices 50:1109–1116. doi:10.1109/TED.2003.812490
Sato N, Shigematsu S, Morimura H, Yano M, Kudou K, Kamei T, Machida K (2004) Highly sensitive CMOS MEMS fingerprint sensor. Tech Dig Sens Symp 21:99–102
Sato N, Shigematsu S, Morimura H, Yano M, Kudou K, Kamei T, Machida K (2005) Novel surface structure and its fabrication process for MEMS fingerprint sensor. IEEE Trans Electron Devices 52:1026–1032. doi:10.1109/TED.2005.846342
Souza RJD, Wise KD (1997) A very high density bulk micromachined capacitive tactile imager. Int Conf Solid State Sens Actuators Chic 2:1473–1476. doi:10.1109/SENSOR.1997.635743
Takao H, Miyasaka M, Kawai H, Hara H, Miyazaki A, Kodaira T, Tam SWB, Inoue S, Shimoda T (2004) Flexible semiconductor devices: fingerprint sensor and electrophoretic display on plastic. Proc 34th European solid-state device research conf, ESSDERC 2004 309–312. doi:10.1109/ESSDER.2004.1356551
Timoshenko SP, Krieger SW (1984) Theory of plates and shells. McGraw-Hill, ISBN: 0-07-Y85820-9
Acknowledgment
This work is financially supported by Malaysian Ministry of Science, Technology and Innovation under the project title “MEMS Devices and Sensing Microstructures”.
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Damghanian, M., Majlis, B.Y. Analysis and design of a wide micro beam as a pressure gauge for high sensitivity MEMS fingerprint sensors. Microsyst Technol 15, 731–737 (2009). https://doi.org/10.1007/s00542-008-0755-4
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DOI: https://doi.org/10.1007/s00542-008-0755-4