心房震顫是臨床上最常見的心律不整，發病嚴重時可能會導致中風、心臟衰竭、死亡。無線電波導管消融手術主要的治療方法，導管消融能在最小的侵入條件下根治疾病。消融的位置和深度會嚴重的影響手術結果，手術的準確度是導管主要發展的目標。目前定位與路徑的精準度都能透過機構達成，超音波能量能夠穿透組織傳遞能量到特定深度。在過去的研究中，超音波消融已經被證實是一個可行的方案，然而要製作成方便定位和完成路徑的環狀陣列結構，還要克服許多問題。
為了發展多通道環狀壓電換能器陣列的超音波消融系統，在這本論文中探討超音波換能器的設計、製程、材料還有驅動議題，進行多次的測試和討論。設計的概念是通過改變接合的型態，讓用來產生超音波的壓電片能固定在基材上還有連接上電路。銅基材連接所有壓電片的下電極的設計能固定壓電片並且降低接線的複雜度。錫焊具有足夠的強度和導電性，在施加超音波輔助之後，接線的良率大幅提升。材料的選擇上考量了加工性還有材料能承受的功率，此外材料的聲學性質被用來推估振動模態，作為壓電片尺寸設計的參考。超音波切割能夠精準的加工鋯鈦酸鉛材料，精度達到微米等級。硬質鋯鈦酸鉛能夠承受-20~80 kV/cm 的電場，厚度方向振動的頻率係數約2000 Hz m。最終製作出的壓電換能器陣列共有20個通道，31模態的共振頻率為4.8 MHz，阻抗為250 Ohms。33模態共振頻率為8.5 MHz，平均阻抗為500 Ohms最低阻抗為345 Ohms。在最佳條件下單通道預估能在7.2 kV/cm的雙極驅動下輸出30 W的能量，以及在20 kV/cm的雙極驅動下輸出116 W的能量。

Atrial fibrillation is the most common arrhythmia in clinical practice. Atrial fibrillation can lead to many serious complications, such as stroke, heart failure, and death. Radio frequency catheter ablation is the main therapy of atrial fibrillation. It can cure the disease in a minimally invasive condition. The accuracy of ablation position and depth is the key issue of this ablation surgery. Positioning and path of ablation can be improved by mechanism design on catheter. Ultrasonic can penetrate tissues and deliver energy into specific depth. The efficacy of ultrasonic ablation has been proved. However, fabricating a small ultrasonic transducer which can emit ultrasound radially to create circumferential lesion in ablation surgery is difficult.
To develop an ablation system with a multichannel circular ultrasonic transducer, the design, processing, material, and driving voltage in this thesis have been tested and discussed. The design concept is by changing the joining method to fixate and electrically contact the piezoelectric ceramic chip. Using a conductive copper substrate to fixate all piezoelectric channel by soldering can create a common ground, thus far reduce the number of wires, and simplify the wiring process. Introduction of longitudinal ultrasonic energy with 28kHz in soldering process, yielding an electrode interface, which provides uniform conductance and enough peeling strength of wire of 0.024kgf. Machinability and working power are the major consideration of material. Moreover, the vibration mode and dimension of transducer are estimated by acoustic properties. Ultrasonic cutting can cut lead-zirconate-titanate ceramic precisely. The error of dimension among each channel is only few microns. The final transducer processed by special soldering and cutting technique has 20 channels, 250 ohms impedance in average in 31 mode, 500 ohms in 33 mode. In optimal condition, the transducer can output 116W mechanical energy in one channel, by input 20kV/cm bipolar sine wave, 30W by 7.2 kV/cm.

[1] Morillo CA, Banerjee A, Perel P, Wood D, Jouven X. Atrial fibrillation: the current epidemic. J Geriatr Cardiol. 2017;14(3):195-203. doi:10.11909/j.issn.1671-5411.2017.03.011
[2] Miyasaka Y, Barnes ME, Gersh BJ, et al. Secular trends in incidence of atrial fibrillation in Olmsted County, Minnesota, 1980 to 2000, and implications on the projections for future prevalence [published correction appears in Circulation. 2006 Sep 12;114(11):e498]. Circulation. 2006;114(2):119-125. doi:10.1161/CIRCULATIONAHA.105.595140
[3] Calkins H, Hindricks G, Cappato R, et al. 2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation: executive summary. J Interv Card Electrophysiol. 2017;50(1):1-55. doi:10.1007/s10840-017-0277-z
[4] Shih, H. T. (2013). U.S. Patent No. 8,585,695. Washington, DC: U.S. Patent and Trademark Office.
[5] Liou, J. C., Peng, C. W., & Chen, Z. X. (2021). Investigation of cylindrical piezoelectric and specific multi-channel circular mems-transducer array resonator of ultrasonic ablation. Micromachines, 12(4), 371.
[6] Nazer B, Giraud D, Zhao Y, et al. High-intensity ultrasound catheter ablation achieves deep mid-myocardial lesions in vivo. Heart Rhythm. 2021;18(4):623-631. doi:10.1016/j.hrthm.2020.12.027
[7] P. Hollender, L. Kuo, V. Chen, S. Eyerly, P. Wolf and G. Trahey, "Scanned 3-D Intracardiac ARFI and SWEI for Imaging Radio-Frequency Ablation Lesions," in IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 64, no. 7, pp. 1034-1044, July 2017, doi: 10.1109/TUFFC.2017.2692558.
[8] Zhou D, Cheung KF, Chen Y, et al. Fabrication and performance of endoscopic ultrasound radial arrays based on PMN-PT single crystal/epoxy 1-3 composite. IEEE Trans Ultrason Ferroelectr Freq Control. 2011;58(2):477-484. doi:10.1109/TUFFC.2011.1825
[9] J. H. Jang et al., "Dual-mode integrated circuit for imaging and HIFU with 2-D CMUT arrays," 2015 IEEE International Ultrasonics Symposium (IUS), 2015, pp. 1-4, doi: 10.1109/ULTSYM.2015.0166.
[10] Bunting E, Papadacci C, Wan E, Sayseng V, Grondin J, Konofagou EE. Cardiac Lesion Mapping In Vivo Using Intracardiac Myocardial Elastography. IEEE Trans Ultrason Ferroelectr Freq Control. 2018;65(1):14-20. doi:10.1109/TUFFC.2017.2768301
[11] Pellegrino PL, Brunetti ND, Gravina D, et al. Nonfluoroscopic mapping reduces radiation exposure in ablation of atrial fibrillation. J Cardiovasc Med (Hagerstown). 2013;14(7):528-533. doi:10.2459/JCM.0b013e328356a4e6
[12] Jordan, T. L., & Ounaies, Z. (2001). Piezoelectric ceramics characterization. INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA.
[13] European standard, EN 50324-1: 2002, “Piezoelectric properties of ceramic materials and components, Part 1: Terms and definitions,” CENELEC European Committee for Electrotechnical Standardization, 2002  
[14] IEEE Standard on Piezoelectricity ANSI/IEEE
[15] Military Standard (1995) Piezoelectric ceramic material and measurements guidelines for sonar transducers. MIL-STD-1376B (SH)
[16] Uchino, K. (Ed.). (2017). Advanced piezoelectric materials: Science and technology. Woodhead Publishing.pp.21-126
[17] Lahmer, T. (2008). Forward and inverse problems in piezoelectricity (Doctoral dissertation, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)).
[18] J. Fialka and P. Beneš, "Measurement of piezoelectric ceramic parameters - A characterization of the elastic, dielectric and piezoelectric properties of NCE51 PZT," Proceedings of the 13th International Carpathian Control Conference (ICCC), 2012, pp. 147-152, doi: 10.1109/CarpathianCC.2012.6228632.
[19] Kholkin, A.; Jadidian B.; Safari, A. In Encyclopedia of Smart Materials, Schwartz, M.; Eds.; ISBN 0-471-17780-6; John Wiley & Sons, Inc.: New York, NY, 2002, Vol.1, pp139 -148
[20] Uchino, K. (Ed.). (2017). Advanced piezoelectric materials: Science and technology. Woodhead Publishing.pp.423-451
[21] T.B. Thoe; D.K. Aspinwall; M.L.H. Wise (1998). Review on ultrasonic machining. , 38(4), 239–255. doi:10.1016/s0890-6955(97)00036-9
[22] Egashira, K., Mizutani, K., & Nagao, T. (2002). Ultrasonic vibration drilling of microholes in glass. CIRP Annals, 51(1), 339-342.
[23] Neppiras, E. A. (1964). Ultrasonic machining and forming. Ultrasonics, 2(4), 167-173.
[24] Weber, H., Herberger, J., & Pilz, R. (1984). Turning of machinable glass ceramics with an ultrasonically vibrated tool. CIRP Annals, 33(1), 85-87.
[25] Xiao, X., Zheng, K., & Liao, W. (2014). Theoretical model for cutting force in rotary ultrasonic milling of dental zirconia ceramics. The International Journal of Advanced Manufacturing Technology, 75(9), 1263-1277.
[26] Ding, A., Wu, Y., & Liu, Y. (2011). Surface topography of fine-grained ZrO2 ceramic by two-dimensional ultrasonic vibration grinding. Journal of Wuhan University of Technology-Mater. Sci. Ed., 26(6), 1162-1165.
[27] Hocheng, H., Kuo, K. L., & Lin, J. T. (1999). Machinability of zirconia ceramics in ultrasonic drilling. Materials and manufacturing processes, 14(5), 713-724.
[28] Lin, S. Y., Kuan, C. H., She, C. H., & Wang, W. T. (2015). Application of ultrasonic assisted machining technique for glass-ceramic milling. International Journal of Mechanical and Mechatronics Engineering, 9(5), 802-807.
[29] Cao, J., Wu, Y., Lu, D., Fujimoto, M., & Nomura, M. (2014). Fundamental machining characteristics of ultrasonic assisted internal grinding of SiC ceramics. Materials and Manufacturing Processes, 29(5), 557-563.
[30] Churi, N. J., Pei, Z. J., Shorter, D. C., & Treadwell, C. (2009). Rotary ultrasonic machining of dental ceramics. International Journal of Machining and Machinability of Materials, 6(3-4), 270-284.
[31] Meng, H., Zheng, K., Xiao, X., & Liao, W. (2017). Investigation on feed direction cutting force in ultrasonic vibration-assisted grinding of dental ceramics. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 231(19), 3493-3503.
[32] Park, K. H., Hong, Y. H., Kim, K. T., Lee, S. W., Choi, H. Z., & Choi, Y. J. (2014). Understanding of ultrasonic assisted machining with diamond grinding tool. Modern Mechanical Engineering, 4(1), 1-7.
[33] Nath, C., Lim, G. C., & Zheng, H. Y. (2012). Influence of the material removal mechanisms on hole integrity in ultrasonic machining of structural ceramics. Ultrasonics, 52(5), 605-613.
[34] S.G. Amin; M.H.M. Ahmed; H.A. Youssef (1995). Computer-aided design of acoustic horns for ultrasonic machining using finite-element analysis. , 55(3-4), 254–260. doi:10.1016/0924-0136(95)02015-2
[35] Cardoni, A., & Lucas, M. (2002). Enhanced vibration performance of ultrasonic block horns. Ultrasonics, 40(1-8), 365-369.
[36] Elangovan, S., Semeer, S., & Prakasan, K. (2009). Temperature and stress distribution in ultrasonic metal welding—An FEA-based study. Journal of materials processing technology, 209(3), 1143-1150.
[37] Cardoni, A., Lucas, M., Cartmell, M., & Lim, F. (2004). A novel multiple blade ultrasonic cutting device. Ultrasonics, 42(1-9), 69-74.
[38] Rani, M. R., Prakasan, K., & Rudramoorthy, R. (2015). Studies on thermo-elastic heating of horns used in ultrasonic plastic welding. Ultrasonics, 55, 123-132.
[39] Roy, Subhankar; Jagadish, (2016). Design of a circular hollow ultrasonic horn for USM using finite element analysis. The International Journal of Advanced Manufacturing Technology, (), –. doi:10.1007/s00170-016-8985-6
[40] Rani, M. R., & Rudramoorthy, R. (2013). Computational modeling and experimental studies of the dynamic performance of ultrasonic horn profiles used in plastic welding. Ultrasonics, 53(3), 763-772.
[41] Vivekananda, K., Arka, G. N., & Sahoo, S. K. (2014). Design and analysis of ultrasonic vibratory tool (UVT) using FEM, and experimental study on ultrasonic vibration-assisted turning (UAT). Procedia Engineering, 97, 1178-1186.
[42] Vianco, P. T. (1993). Robust solder joint attachment of coaxial cable leads to piezoelectric ceramic electrodes. IEEE transactions on ultrasonics, ferroelectrics, and frequency control, 40(5), 544-550.
[43] Wilson, C., Thompson, L., Choi, H., & Bostwick, J. B. (2021). Enhanced wettability in ultrasonic-assisted soldering to glass substrates. Journal of Manufacturing Processes, 64, 276-284.
[44] Kim, Y. S., Kim, S. H., Lee, K., & Paik, K. W. (2013). Ultrasonic-assisted thermocompression bonding method of solder anisotropic conductive film joints for reliable camera module packaging. IEEE Transactions on Components, Packaging and Manufacturing Technology, 3(12), 2156-2163.
[45] Kago, K., Suetsugu, K., Hibino, S., Ikari, T., Furusawa, A., Takano, H., ... & Matsushige, K. (2004). Novel ultrasonic soldering technique for lead-free solders. Materials Transactions, 45(3), 703-709.
[46] Rheingans, B., Jeurgens, L. P., & Janczak-Rusch, J. (2022). Fast and Reliable Ag–Sn Transient Liquid Phase Bonding by Combining Rapid Heating with Low-Power Ultrasound. Metallurgical and Materials Transactions A, 53(6), 2195-2207.
[47] Antonevich, J. N. (1976). Fundamentals of ultrasonic soldering. Welding Journal, 55(7), 200s-207s.
[48] Lanin, V. L. (2001). Ultrasonic soldering in electronics. Ultrasonics Sonochemistry, 8(4), 379-385.
[49] Ma, L., Xu, Z., Zheng, K., Yan, J., & Yang, S. (2014). Vibration characteristics of aluminum surface subjected to ultrasonic waves and their effect on wetting behavior of solder droplets. Ultrasonics, 54(3), 929-937.
[50] Tan, A. T., Tan, A. W., & Yusof, F. (2017). Effect of ultrasonic vibration time on the Cu/Sn-Ag-Cu/Cu joint soldered by low-power-high-frequency ultrasonic-assisted reflow soldering. Ultrasonics sonochemistry, 34, 616-625.
[51] Ji, H., Wang, Q., Li, M., & Wang, C. (2014). Ultrafine-grain and isotropic Cu/SAC305/Cu solder interconnects fabricated by high-intensity ultrasound-assisted solidification. Journal of electronic materials, 43(7), 2467-2478.