目前聲波感測器(Acoustic Sensor)已被廣泛的應用於質量感測上，包含了表面聲波(SAW)感測器、彎曲平板波(FPW)感測器、剪應力(TSM)震盪器、剪力水平板波(SH-APM)感測器，其中又因彎曲平板波(Flexural Plate Wave, FPW)微型感測元件具高質量靈敏度、低傳播速度與低工作頻率等特性，特別適用於需液態測量的環境，如生醫感測，液體黏滯性測量等應用；然而因元件具有感測訊號插入損失較大且容易受雜訊干擾等缺點，不易與後端IC電路整合成微系統，故為了改善其缺點，所以本論文將利用微機電系統(MEMS)技術設計改變交指叉式電極(Interdigital Transducer, IDT)之結構且結合高C軸取向之壓電薄膜研發出具有低訊號插入損失、低工作頻率、高機電轉換特性之FPW元件。
本研究首先利用RF-Sputter開發出一具繞射角度為34.2o其繞射強度高達20944 A.U.，半高寬(Full Width at Half Maximum, FWHM)為0.573o之氧化鋅壓電感測薄膜，並經由包括五次黃光微影(Photolithography)與七次薄膜沉積之製程開發出工作頻率約為0.1 MHz，訊號之插入損失在11 dB到14 dB，機電耦合系數(Electromechanical Coupling Coefficient, K2)高達11 %之FPW元件。由量測結果特性顯示本研究已成功研發改良出FPW元件。

Acoustic micro-sensors have already been applied in mass sensing including surface acoustic wave (SAW), flexural plate wave (FPW), thickness shear mode (TSM) and shear horizontal acoustic plate mode (SH-APM). The FPW micro-sensor is very suitable for liquid-sensing and bio-sensing applications due to the high mass-sensitivity and low phase-velocity in liquid. However, the conventional FPW micro-sensors presented a high insertion-loss (IL) and a low signal-to-noise ratio so it is difficult to combine with IC into a micro-system.
To overcome these drawbacks, this study combine the Microelectromechanical System (MEMS) technology and the high C-axis orientation ZnO piezoelectric thin-film to develop a low insertion loss, low operation frequency, and high electromechanical coupling coefficient FPW device. In this study, a high C-axis orientation ZnO piezoelectric thin-film with a 20944A.U. X-Ray diffraction intensity at 34.200 degree and a 0.573 degree full width at half maximum (FWHM) was deposited by a commercial magnetic radio-frequency (RF) sputter system. The total processes of the FPW micro-sensor included five photolithography and seven thin-film depositions. In this study a low operation frequency (0.1MHz), low insertion loss (11dB to 14dB) and high electromechanical coupling coefficient (11%) FPW sensor was developed and fabricated.

摘要.............................................................................................................I
Abstract.................................................................................................... III
誌謝.......................................................................................................... V
目錄..........................................................................................................VI
圖目錄.....................................................................................................VII
表目錄......................................................................................................IX
第一章 緒論..............................................................................................1
1-1 前言..............................................................................................1
1-2 研究動機......................................................................................4
1-3 文獻回顧......................................................................................5
1-3-1 剪應力(Thickness shear mode, TSM)震盪器……..….…5
1-3-2 表面聲波(Surface Acoustic Wave, SAW)感測器….....…6
1-3-3 剪力水平板波(Shear Horizontal Acoustic Plate Mode, SH-APM)感測器…………………………….…..7
1-3-4 彎曲平板波(Flexural Plate Wave, FPW)感測器………...8
第二章 彎曲平板波元件之理論與分析................................................14
2-1彎曲平板波元件之研究.............................................................14
2-1-1彎曲平板波元件之相速度理論推導...............................15
2-1-2金屬指叉式電極之等效電路分析...................................17
2-2 壓電材料分析...........................................................................22
2-2-1壓電薄膜材料選擇...........................................................24
2-2-2氧化鋅壓電薄膜晶格結構與特性之簡介.......................25
2-2-3 氧化鋅薄膜沉積方式………..........................................27
2-2-4 反應性射頻磁控濺鍍原理簡介......................................27
2-2-5 壓電薄膜X光繞射分析..................................................30
第三章 元件設計與製作流程..............................................................33
3-1 FPW元件之光罩佈局設計……………………........................33
3-2 FPW元件之製程整合設計……................................................38
3-2-1 FPW元件之製作流程......................................................38
3-2-2 詳細製程步驟與參數......................................................40
3-3 實驗設備規格............................................................................46
第四章 結果與討論................................................................................54
4-1 氧化鋅薄膜之材料特性分析....................................................54
4-2元件量測結果與分析.................................................................61
第五章 結果與未來展望........................................................................75
5-1 結論............................................................................................75
5-2 未來展望....................................................................................76
參考文獻..................................................................................................77

[1] 「微機電系統技術與應用」 ，行政院國家科學委員會精密儀器發展中心出版，2003。
[2] D. S. Ballantine and David Stephen, “Acoustic wave sensor: theory,design, and physico-chemical applications,” San Diego, Academic Press, Inc., 1997.
[3] R. W. Cernosek, “An Overview of Acoustic Wave Devices for chemical&biological sensing, Biological Detection, and Materials Characterization,” Solid-State Sensor Lecture, Auburn University, Auburn, AL, 2002.
[4] 李其源，「蝕刻晶片厚度即時監控之新穎方法」，國立台灣大學機械工程研究所博士論文，2004。
[5] 吳德春，「薄膜式表面聲波元件之製作與分析」，中原大學電子工程學系碩士論文，2002。
[6] D. W. Galipeau, P. R. Story, K. A. Vetelino and R. D. Mileham,“surface acoustic wave microsensors and applications,” Smart Mater.Struct. 6, pp.658-667, 1997
[7] A. Pohl, “A review of wireless SAW sensors,” IEEE Trans. Ultras. Ferr. Freq. Contr. 47, pp.317-332, 2000
[8] B. Drafts, “Acoustic Wave Technology Sensors,” IEEE Trans. On Microwave Theory and Techniques, vol. 49, No. 4, 2001
[9] M. J. Velekoop, “Acoustic wave sensors and their technology,” Ultrasonics, vol. 36, pp.7-14, 1998
[10] M. E. Motamedi and R. M. White, “Acoustic sensor in semiconductor Sensor,” John Wiely & Sons, Inc.,New York, 1994.

[11] M. S. Weinberg, B. T. Cunningham, C. W. Clapp, “Modeling Flexural Plate Wave Device,” IEEE J. Microelectromechanical Systems, vol. 9, No.3, pp.370 – 379, 2000.
[12] T. Laurent, F. O. Bastien, J. C. Pommier, A. Cachard, D. Remiens, E. Cattan, “Lamb Wave and plate mode in ZnO/silicon and AlN/silicon membrane Application to sensors able to operate in contact with liduid,” Sensor and Actuator 87, pp. 26-37, 2000.
[14] J. W. Gardner, Vijay k. Varadan and Osama O. Awadelkarim, “Microsensors MEMS and Smart Devices” John Wiely & Sons, Inc., 2001.
[15] 余嘉銘，「壓電彎曲平板波生物感測器」，國立中正大學電機工程研究所碩士論文，2003。
[16] W.R. Smith, H.M. Gerard, J.H. Collins, T.M. Reeder, and H.J. Shaw, “Analysis of Interdigital Surface Wave Transducers by Use of Equivalent Circuit Model,” IEEE Trans. Microwave Theory and Techniques, vol. MTT-17, No.11, pp.856-864, Nov. 1969.
[17] T. Mitsuyu, S. Ono, and K. Wasa, “Structures and SAW properties ofrf-sputtered single-crystal films of ZnO on sapphire,” Journal of Applied Physics, vol.51 p.2464-2470, 1980.
[18] V. Mortet, O. Elmazria, M. Nesladek, M. B. Assouar, “Surface acoustic wave propagation in aluminum nitride-unpolished freestanding diamond structures,” Applied Physics Letters, vol.81 p.1720-1722, 2002.
[19] Yoshihiko Shibata, Kiyoshi Kaya, and Kageyasu Akashi, “Epitaxial growth and surface acoustic wave properties of lithium niobate films grown by pulsed laser deposition,” Journal of Applied Physics, vol.77 p.1498-1503, 1995.
[20] 林素霞，「氧化鋅薄膜的特性改良及應用之研究」，國立成功大學材料科學及工程研究所博士論文，2003。
[21] B. T. khuri-Yakub, J. G. Smits and T. Barbee, “Reactive magnetron sputtering of ZnO,” J. Appl. Phys.52(7), p.4772-4774, July 1981.
[22] Y. Yoshino, T. Makino, Y. Katayama and T. Hata, “Optimization of zinc oxide thin film for surface acoustic wave filters by ratio frequency sputtering,” Vacuum 59, p.538-545, 2000.
[23] Hong Xiao原著，羅正忠、張鼎張譯，「半導體製程技術導論」，學銘圖書。
[24] 汪建民主編，「材料分析」，中國材料科學學會。