本研究運用CMOS MEMS技術設計出微電容式超音波感測器，特色是整合電路和感測器於單一晶片，能有效的降低寄生電容，研究所使用的製程為TSMC 0.18 μm 1P6M CMOS Process，選用特有MIM電容作為感測結構的設計，選擇厚度較薄的金屬層(CTM層)作為犧牲層，為了降低空腔的厚度獲得更高的感測電容值；透過濕蝕刻成功的釋放結構，並藉由2微米的二氧化矽的封裝，感測器成功在水中進行超音波量測，實驗結果顯示直徑的80 μm圓形結構共振頻率達5.8 MHz，感測頻寬為2.2 MHz，感測度為249.1 (mV_pp)⁄(MPa/V)，其各種特性均比以前使用TSMC 0.35 μm 2P4M CMOS Process 製作的感測器較好。

This work presents a capacitive ultrasonic sensor chip fabricated by the CMOS-MEMS technology. The unique feature of this work is integrating the circuit and the sensor on the same chip, which can efficiently reduce the parasitic capacitance. This work used the TSMC 0.18-μm 1P6M CMOS process, for fabrication, in which the MIM capacitors are used as our sensing structure. The thin CTM layer is used as the sacrificial layer in order to reduce the air cavity thickness for achieving higher sensitivity than our previous work.
The structure is successfully released by wet etching and sealed by 2-μm silicon dioxide. The fabricated capacitive ultrasonic sensor is tested in water. The microstructure has an 80-μm diameter. The measured resonant frequency, band width and sensitivity are 5.8 MHz, 2.2 MHz, and 249.1 (mV_pp)⁄(MPa/V), respectively, which are better than the previous devices fabricated in the TSMC 0.35-μm 2P4M CMOS process .

摘要 I
Abstract II
致謝 III
目錄 IV
圖目錄 VI
表目錄 X
第一章 緒論 1
1.1簡介 1
1.2研究動機 3
1.3互補式金氧半導體微機電系統簡介 5
1.4文獻回顧 6
第二章 架構超音波感測器之設計與模擬 9
2.1 電容式超音波感測原理 10
2.2後製程 15
2.3結構設計與模擬 16
2.4電路設計與模擬 22
第三章 量測結果 33
3.1 後製程結果 33
3.2 感測電路量測 36
3.3 超音波實驗 39
3.4 結構改善 48
第四章 結論 51
4.1 研究成果與討論 51
4.2 未來工作 53
參考文獻 54
附錄 57

[1] Y. V. Gulyaev, and F. S. Hickernell, “Acoustoelectronics: istory, present state, and new ideas for a new era,” IEEE Ultrasonics Symposium, pp. 182-190, 2004.

[2] M. Xu, and L. V. Wang, “Photoacoustic imaging in biomedicine,” Review of Scientific Instruments, vol. 77, 041101, 2006.

[3] J. Yao, and L. V. Wang, “Breakthroughs in photonics 2013: photoacoustic tomography in biomedicine,” IEEE Photonics Journal, vol. 6, no. 2, pp. 1-7, Apr. 2014.

[4] X. Jin, I. Ladabaum, and B. T. Khuri-Yakub, “The microfabrication of capacitive ultrasonic transducers,” Journal of Microelectro -mechanical Systems, vol. 7, no. 3, pp. 295-302, Sep. 1998.

[5] X. Cheng, J. Chen, C. Li, J.-H. Liu, I-M. Shen, and P.-C. Li, “A miniature capacitive ultrasonic imager array,” IEEE Sensors Journal, vol. 9, no. 5, pp. 569-577, May, 2009.

[6] I. Ladabaum, X. Jin, H. T. Soh, A. Atalar, and B. T. Khuri-Yakub, “Surface micromachined capacitive ultrasonic transducers,” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 45, no. 3, pp. 678-690, May, 1998.

[7] J. Chen, X. Cheng, C.-C. Chen, P.-C. Li, J.-H. Liu, and Y.-T. Cheng, “A capacitive micromachined ultrasonic transducer array for minimally invasive medical diagnosis,” Journal of Microelectro -mechanical Systems, vol. 17, no. 3, pp. 599-610, Jun. 2008.

[8] S. H. Wong, M.Kupnik, R. D. Watkins, K. Butts-Pauly, and B. T. Khuri-Yakub, “Capacitive micromachined ultrasonic transducers
for therapeutic ultrasound applications,” IEEE Transactions on Biomedical Engineering, vol. 57, no. 1, pp. 114-123, Jan. 2010.



[9] C. B. Doody, X. Cheng, C. A. Rich, D. F. Lemmerhirt, and R. D. White, “Modeling and characterization of CMOS-fabricated
capacitive micromachined ultrasound transducers,” Journal of Microelectromechanical Systems, vol. 20, no. 1, pp. 104-118, Feb. 2011.

[10] P.-K. Tang, P.-H. Wang, M.-L. Li and M. S.-C. Lu, “Design and characterization of the immersion-type capacitive ultrasonic sensors fabricated in a CMOS process,” Journal of Micromechanics and Microengineering, 21, pp. 1-8, 2011.

[11] M.-L. Li, P.-H. Wang, P.-L. Liao, and M. S.-C. Lu, “Three -dimensional photoacoustic imaging by a CMOS micromachined capacitive ultrasonic sensor,” IEEE Electron Device Letters, vol. 32, no. 8, pp. 1149-1151, Aug. 2011.

[12] S. Trolier-Mckinstry, and P. Muralt, “Thin Film Piezoelectrics for MEMS,” Journal of Electroceramics, 12, pp. 7–17, 2004.

[13] F. Akasheh, T. Myers, J. D. Fraser, S. Bose, A. Bandyopadhyay, “Development of piezoelectric micromachined ultrasonic transducers,” Sensors and Actuators A 111, pp. 275–287, 2004.

[14] M. A. Tadayon, and S. Ashkenazi, “Optical micromachined ultrasound transducers (OMUT)- a new approach for high-frequency transducers,” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 60, no. 9, pp. 2021-2030, Sep. 2013.

[15] H. T. Soh, I. Ladabaum, A. Atalar, C. F. Quate, and B. T. Khuri-Yakub, “Silicon micromachined ultrasonic immersion transducers,” Applied Physics Letters, vol. 69, pp. 3674-3676, Dec. 1996.

[16] A. Bhuyan, J. W. Choe, B. Chul Lee, I. O. Wygant, , A. Nikoozadeh, Ö. Oralkan, and B. T. Khuri-Yakub, “Integrated circuits for volumetric ultrasound imaging with 2-D CMUT arrays,” IEEE Transactions on Biomedical Circuits and Systems, vol. 7, no. 6, pp. 796-804, Dec. 2013.
[17] A. Bozkurt, I. Ladabaum, A. Atalar, and B. T. Khuri-Yakub, “Theory and analysis of electrode size optimization for capacitive icrofabricated ultrasonic transducers,” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 46, no. 6, pp. 1364-1374, Nov. 1999.

[18] A. S. Ergun, Y. Huang, X. Zhuang, Ö. Oralkan, Goksen G. Yaralıoglu, and B. T. Khuri-Yakub, “Capacitive micromachined ultrasonic transducers: fabrication technology,” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 52, no. 12, pp. 2242-2258, Dec. 2005.

[19] P. C. Eccardt, and K. Niederer, “Micromachined ultrasound transducers with improved coupling factors from a CMOS compatible process,” Ultrasonics, vol. 38, pp. 774-780, 2000.

[20] A. Logan, and J. T. W. Yeow, “Fabricating capacitive micromachined ultrasonic transducers with a novel silicon-nitride-based wafer bonding process,” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 56, no. 5, pp. 1074-1084, May, 2009.

[21] Y. Huang, A. S. Ergun, E. Hæggström, M. H. Badi, and B. T. Khuri-Yakub, “Fabricating capacitive micromachined ultrasonic transducers with wafer-bonding technology,” Journal of Microelectromechanical Systems, vol. 12, no. 2, pp. 128-137, Apr. 2003.

[22] P. Zhang, G. Fitzpatrick, T. Harrison, W. A. Moussa, and R. J. Zemp, “Double-SOI wafer-bonded CMUTs with improved electrical safety and minimal roughness of dielectric and electrode surfaces,” Journal of Microelectromechanical Systems, vol. 21, no. 3, pp. 668-680, Jun. 2012.