In order to measure dynamically the local temperature or wall shear stress of a flow, a new structure of flexible hot-film sensor array and its fabrication process are proposed. The thermal sensing material, nickel, is sputtered on a polymide flexible substrate, and then patterns to form both the thermal resistor array and the leads' sublayer, on which copper is electroplated and lift-off patterned to form the metal leads. Electroplating can realize economically higher thickness of the lead film than does sputtering to keep the lead resistance small and minimize its influence on thermal sensing. High temperature coefficient of resistance (TCR) is obtained over 3.6×10-3/℃ with nonlinearity under 0.7%. Wind tunnel experiments show that the developed sensor can measure wall shear stress with high repeatability. This flexible sensor array possesses reliable connections between the flexible thermal resistors and leads, and can be used to measure the dynamic distribution of flow parameters on non-planar surfaces.
MA Binghe, FU Bo, LI Jianqiang, DENG Jinjun, DONG Shuancheng
. Flexible Hot-film Sensor Array Fabricated with Sputtering-electroplating Micromachining[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2011
, 32(11)
: 2147
-2152
.
DOI: CNKI:11-1929/V.20110712.0904.001
[1] Xiang D, Yang Y B, Xu Y, et al. MEMS-based shear-stress sensor for skin-friction measurements// Instrumentation and Measurement Technology Conference (I2MTC) 2010 IEEE. 2010: 656-661.
[2] Jiang F K, Lee G B, Tai Y C, et al. A flexible micromachine-based shear-stress sensor array and its application to separation-point detection[J]. Sensors and Actuators, 2000, 79(3): 194-203.
[3] Shi S D, Chen D P, Bai H L, et al. A novel micro thermal shear stress sensor with a cavity underneath//Proceedings of the 1st IEEE International Conference on Nano/Micro Engineered and Molecular Systems. 2006: 466-469.
[4] Yan W P, Li H N, Kuang Y B, et al. Nickel membrane temperature sensor in micro-flow measurement[J]. Journal of Alloys and Compounds, 2008, 449(1-2): 210-213.
[5] Liu C, Huang J B, Zhu Z J, et al. A micromachined flow shear stress sensor based on thermal transfer principles[J]. Journal of Microelectromechanical Systems, 1999, 8(1): 90-99.
[6] Lee G B, Huang F C, Lee C Y, et al. A new fabrication process for a flexible skin with temperature sensor array and its applications[J]. Acta Mechanica Sinica, 2004, 20(2): 140-145.
[7] Lee C Y, Wu G W, Hsieh W J. Fabrication of micro sensors on a flexible substrate[J]. Sensors and Actuators A: Physical, 2008, 147(1): 173-176.
[8] 肖素艳, 车录锋, 李昕欣, 等. 基于柔性MEMS皮肤技术温度传感器阵列的研究[J]. 光学精密工程, 2005, 13(6): 674-680. Xiao Suyan, Che Lufeng, Li Xinxin, et al. A temperature sensor array based on flexible MEMS skin technology [J]. Optics and Precision Engineering, 2005, 13(6): 674-680. (in Chinese)
[9] Xiao S Y, Che L F, Li X X, et al. A novel fabrication process of MEMS devices on polyimide flexible substrates[J]. Microelectronic Engineering, 2008, 85(2): 452-457.
[10] 马炳和, 赵建国, 邓进军, 等. 全柔性热膜微传感器阵列制造工艺及性能优化[J]. 光学精密工程, 2009, 17(8): 1971-1977. Ma Binghe, Zhao Jianguo, Deng Jinjun, et al. Fabrication of flexible hot film sensor array and its optimization[J]. Optics and Precision Engineering, 2009, 17(8): 1971-1977. (in Chinese)
[11] Buder U, Petz R, Kittel M, et al. AeroMEMS polyimide based wall double hot-wire sensors flow separation detection[J]. Sensors and Actuators A: Physical, 2008, 142(1): 130-137.
[12] Ngo L, Kupke W, Seidel H, et al. Simulation and experimental results of a hot-film anemometer array on a flexible substrate//CANEUS 2004--Conference on Micro-Nano-Technologies. 2004.
[13] Schmid U, Ababneh A, Seidel H, et al. Characterization of aluminium nitride and aluminium oxide thin films sputter-deposited on organic substrates[J]. Microsystem Technologies, 2008, 14(4-5): 483-490.
[14] Berns A, Obermeier E, Wang X, et al. AeroMEMS sensor with integrated pressure and hot-wire sensor for high-frequency transition detection//Proceedings of the 47th AIAA Aerospace Sciences Meeting Including The New Horizons Forum and Aerospace Exposition. 2009.
[15] 张以忱, 巴德纯, 刘希东, 等. 温度传感功能薄膜技术[J]. 真空技术与科学, 2003, 23(5): 334-339, 346. Zhang Yichen, Ba Dechun, Liu Xidong, et al. Latest progress in development of thin film temperature sensors[J]. Vacuum Science and Technology, 2003, 23(5): 334-339, 346. (in Chinese)