近年來，精細銀導線成為電子封裝的重點發展材料之一，其相對於傳
統的打線材料，如金導線、銅導線或鍍鈀銅線等具有更優異的電與熱特性。然而，銀導線與鋁襯墊接合時容易受到環境腐蝕的影響，進而導致接合強度不足。為了改善上述缺點，銀導線系統添加入金與鈀作為合金元素，可大幅提高其抗電遷移特性與接合可靠度。現今的銀基導線發展多集中於銀合金線，然而在銀線中加入鈀與金等合金元素將造成導線的電阻率大幅增加。另一方面，銀線中加入鈀會使得材料變硬脆，進而增加伸線製程的斷線機率與模具耗損。基於此，銀合金線多作為一替代方案於光電產業中使用。
無氰鍍金銀線是一具有奈米級金鍍層的微細導線，該線材可滿足現今
封裝產業之打線要求。與傳統銀導線相比，鍍金銀線具有良好的接合強度並可長時間存放於大氣環境中。然而，目前尚未有研究對此新型線材的抗氧化、抗硫化與接合特性等關鍵因子進行系統性調查，故本研究將針對鍍金銀線的表面特徵、高溫電性、推球失效模式、拉伸破斷機制與介金屬化合物等進行一系列探討與評估。本論文發現退火 550°C 之鍍金銀線具有穩定的微觀組織與良好機械性質。鍍金銀線於時效 175°C/ 500 小時後，金屬球與鋁墊間可觀察到介金屬化合物 Ag 2 Al 與 AuAl 2 生成。另一方面，氧化和硫氣試驗可證實銀線表面的金鍍層可有效提升線材耐蝕性。高溫偏壓耐受性試驗亦顯示鍍金線材在 125°C 的測試環境中可保持與室溫環境同等的電特性。上述結果顯示金鍍層於嚴苛環境中具有保護芯部銀線之作用。
本論文對鍍金銀線做了基礎性評估，並拓展出鍍鈀金層銀線與化鍍金
銀線，比較結果顯示兩款新型線材具有良好的打線操作性與低電阻特性，兩線材皆可應用於先進封裝製程中。

This report presents a novel Au coated Ag wire (ACA wire), prepared by a cyanide-free bath method. In this report, ACA wire, annealed at 550 degrees C was found to induce the stable microstructure and excellent mechanical properties. After the long-term current test, the ACA wire was found to have improved electrical properties, due to the equiaxed grain growth. The ACA wire offers an oxidation-resistant layer and added benefits compared with Ag and Ag-4pd wires. For automotive electronics packaging applications, electrical properties at high temperature manifest that an ACA wire still maintains superior electrical resistivity.
We also developed the Au-coated Ag wire-chemical (ACA-C wire) and the Pd-Au coated Ag wire (PCA wire), which can be improved to 2nd bond performance and attained without wire fracture during the drawing process. Results of our study
provide insights regarding the reliability issue in advanced bonding processes.

[1] Harman, G. (2009). Wire bonding in microelectronics, 3/E. McGraw Hill Professional.
[2] Harman, G. G., & Albers, J. (1977). The ultrasonic welding mechanism as applied to aluminum-and gold-wire bonding in microelectronics. IEEE Transactions on Parts, Hybrids, and Packaging, 13(4), 406-412.
[3] Chauhan, P. S., Choubey, A., Zhong, Z., Pecht, M. G. (2014). Copper wire bonding. Springer.
[4] Takahashi, Y., Inoue, M. (2002). Numerical study of wire bonding-Analysis of interfacial deformation between wire and pad. Journal of Electronic Packaging, 124(1), 27-36.
[5] Baker, D., Bryan, I. E. (1965). An improved form of thermocompression bond. British Journal of Applied Physics, 16(6), 865-871.
[6] Prasad, S. K. (2004). Advanced wirebond interconnection technology. Springer Science & Business Media.
[7] Or, S. W., Chan, H. L. W., Lo, V. C., Yuen, C. W. (1998). Ultrasonic wire-bond quality monitoring using piezoelectric sensor. Sensors and Actuators A: Physical, 65(1), 69-75.
[8] Murali, S., Srikanth, N., Vath, C. J. (2004). Effect of wire size on the formation of intermetallics and Kirkendall voids on thermal aging of thermosonic wire bonds. Materials Letters, 58(25), 3096-3101.
[9] Murali, S., Srikanth, N., Wong, Y. M., Vath III, C. J. (2007). Fundamentals of thermo-sonic copper wire bonding in microelectronics packaging. Journal of Materials Science, 42(2), 615-623.

[10] Tseng, Y. W., Hung, F. Y., Lui, T. S., Chen, M. Y., Hsueh, H. W. (2015). Effect of annealing on the microstructure and bonding interface properties of Ag-2Pd alloy wire. Microelectronics Reliability, 55(8), 1256-1261.
[11] Wang, C., Sun, R. (2009). The quality test of wire bonding. Modern Applied Science, 3(12), 50-56.
[12] Joule, J. P. (1841). On the heat evolved by metallic conductors of electricity, and in the cells of a battery during electrolysis. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 19(124), 260-277.
[13] Hsueh, H. W., Hung, F. Y., Lui, T. S., Chen, L. H., Chang, J. K. (2014). Microstructure, electric flame-off (EFO) characteristics and tensile properties of silver-lanthanum alloy wire. Microelectronics Reliability, 54(11), 2564-2569.
[14] Loh, E. (1983). Physical analysis of data on fused-open bond wires. IEEE Transactions on Components, Hybrids, and Manufacturing Technology, 6(2), 209-217.
[15] Ogawa, E. T., Lee, K. D., Blaschke, V. A., Ho, P. S. (2002). Electromigration reliability issues in dual-damascene Cu interconnections. IEEE Transactions on Reliability, 51(4), 403-419.
[16] Liu, Y., Diefendorf, R. J. (1997). On stress evolution and interaction during electromigration in near bamboo structure lines. Applied physics letters, 71(21), 3171-3173.
[17] Cho, J., Thompson, C. V. (1989). Grain size dependence of electromigration-induced failures in narrow interconnects. Applied Physics Letters, 54(25), 2577-2579.

[18] Hau-Riege, C. S. (2004). An introduction to Cu electromigration. Microelectronics Reliability, 44(2), 195-205.
[19] Hsueh, H. W., Hung, F. Y., Lui, T. S., Chen, L. H. (2013). Effect of the direct current on microstructure, tensile property and bonding strength of pure silver wires. Microelectronics Reliability, 53(8), 1159-1163.
[20] Chang, H. S., Hsieh, K. C., Martens, T., Yang, A. (2004). Wire-bond void formation during high temperature aging. IEEE Transactions on Components and Packaging Technologies, 27(1), 155-160.
[21] Yu, C. F., Chan, C. M., Chan, L. C., Hsieh, K. C. (2011). Cu wire bond microstructure analysis and failure mechanism. Microelectronics Reliability, 51(1), 119-124.
[22] Tomiyama, S., Fukui, Y. (1982). Gold bonding wire for semiconductor applications. Gold Bulletin, 15(2), 43-50.
[23] Liu, D. S., Chao, Y. C. (2003). Effects of dopant, temperature, and strain rate on the mechanical properties of micrometer gold-bonding wire. Journal of Electronic Materials, 32(3), 159-165.
[24] Lichtenberger, H., Toea, G., Zasowski, M. (1997). Development of low loop, long length, hydrostatically extruded bonding wire. IEEE in Advanced Packaging Materials Proceedings, 120-123.
[25] Breach, C. D. (2010). What is the future of bonding wire? Will copper entirely replace gold?. Gold Bulletin, 43(3), 150-168.
[26] Zhong, Z. W., Ho, H. M., Tan, Y. C., Tan, W. C., Goh, H. M., Toh, B. H., Tan, J. (2007). Study of factors affecting the hardness of ball bonds in copper wire bonding. Microelectronic Engineering, 84(2), 368-374.
[27] Chuang, T. H., Wang, H. C., Tsai, C. H., Chang, C. C., Chuang, C. H., Lee, J. D., Tsai, H. H. (2012). Thermal stability of grain structure and material properties in an annealing-twinned Ag-8Au-3Pd alloy wire. Scripta Materialia, 67(6), 605-608.
[28] Hung, F. Y., Lui, T. S., Chen, L. H., Lin, Y. C. (2010). Recrystallization, electric flame-off characteristics, and electron backscatter diffraction of copper bonding wires. IEEE Transactions on Advanced Packaging, 33(1), 58-63.
[29] Murali, S., Srikanth, N., Vath, C. J. (2003). Grains, deformation substructures, and slip bands observed in thermosonic copper ball bonding. Materials Characterization, 50(1), 39-50.
[30] Huang, I. T., Hung, F. Y., Lui, T. S., Chen, L. H., Hsueh, H. W. (2011). A study on the tensile fracture mechanism of 15μm copper wire after EFO process. Microelectronics Reliability, 51(1), 25-29.
[31] Drozdov, M., Gur, G., Atzmon, Z., Kaplan, W. D. (2008). Detailed investigation of ultrasonic Al-Cu wire-bonds: I. Intermetallic formation in the as-bonded state. Journal of Materials Science, 43(18), 6029-6037.
[32] Kaimori, S., Nonaka, T., Mizoguchi, A. (2006). The development of Cu bonding wire with oxidation-resistant metal coating. IEEE Transactions on Advanced Packaging, 29(2), 227-231.
[33] Schneider-Ramelow, M., Geißler, U., Schmitz, S., Grübl, W., Schuch, B. (2013). Development and status of Cu ball/wedge bonding in 2012. Journal of Electronic Materials, 42(3), 558-595.
[34] Hsueh, H. W., Hung, F. Y., Lui, T. S., Chen, L. H. (2011). Microstructure, electric flame-off characteristics and tensile properties of silver bonding wires. Microelectronics Reliability, 51(12), 2243-2249.
[35] Choi, M. R., Kim, H. G., Lee, T. W., Jeon, Y. J., Ahn, Y. K., Koo, K. W. Kang, I. T. (2015). Microstructural evaluation and failure analysis of Ag wire bonded to Al pads. Microelectronics Reliability, 55(11), 2306-2315.
[36] Cho, J. S., Yoo, K. A., Moon, J. T., Son, S. B., Lee, S. H., Oh, K. H. (2012). Pd effect on reliability of Ag bonding wires in microelectronic devices in high-humidity environments. Metals and Materials International, 18(5), 881-885.
[37] Chuang, T. H., Lin, H. J., Chuang, C. H., Tsai, C. H., Lee, J. D., Tsai, H. H. (2014). Durability to electromigration of an annealing-twinned Ag-4Pd alloy wire under current stressing. Metallurgical and Materials Transactions A, 45(12), 5574-5583.
[38] Liqun, G., Qiang, C., Juanjuan, L., Zhengrong, C., Jianwei, Z., Maohua, D., Chung, M. (2013). Comparison of Ag wire and Cu wire in memory package. ECS Transactions, 52(1), 747-751.
[39] Ly, N., Xu, D. E., Song, W. H., Mayer, M. (2014). More uniform Pd distribution in free-air balls of Pd-coated Cu bonding wire using movable flame-off electrode. Microelectronics Reliability, 55(1), 201-206.
[40] Persic, J., Pisigan, J. L., Tanna, S., Guo, Y., Song, W. H., Mayer, M. (2012). Low-cost Palladium coating process and its effect on free-air-ball softness and second bond strength of Cu bonding wires. IEEE In Electronic Components and Technology, 62, 1169-1173.
[41] Thompson, M. R. (1941). The constitution and properties of cyanide plating baths. Transactions of the Electrochemical Society, 79(1), 417-437.
[42] Cathro, K. J., Koch, D. F. A. (1964). The anodic dissolution of gold in cyanide solutions. Journal of the Electrochemical Society, 111(12), 1416-1420.

[43] Mudder, T. I., Botz, M. M. (2004). Cyanide and society: a critical review. European Journal of Mineral Processing and Environmental Protection, 4(1), 62-74.
[44] Kato, M., Okinaka, Y. (2004). Some recent developments in non-cyanide gold plating for electronics applications. Gold Bulletin, 37(1-2), 37-44.
[45] Dimitrijević, S., Rajčić-Vujasinović, M., Trujić, V. (2013). Non-cyanide electrolytes for gold plating-a review. International Journal of Electrochemical Science, 8, 6620-6646.
[46] Nagamachi, S., Yamakage, Y., Maruno, H., Ueda, M., Sugimoto, S., Asari, M., Ishikawa, J. (1993). Focused ion beam direct deposition of gold. Applied physics letters, 62(17), 2143-2145.
[47] Gan, C. L., Hashim, U. (2015). Evolutions of bonding wires used in semiconductor electronics: perspective over 25 years. Journal of Materials Science: Materials in Electronics, 26(7), 4412-4424.
[48] Chuang, T. H., Lin, H. J., Wang, H. C., Chuang, C. H., Tsai, C. H. (2015). Mechanism of Electromigration in Ag-Alloy Bonding Wires with Different Pd and Au Content. Journal of Electronic Materials, 44(2), 623-629.
[49] Wu, W., Yuan, J. S., Kang, S. H., Oates, A. S. (2001). Electromigration subjected to Joule heating under pulsed DC stress. Solid-State Electronics, 45(12), 2051-2056.
[50] Lu, L., Shen, Y., Chen, X., Qian, L., Lu, K. (2004). Ultrahigh strength and high electrical conductivity in copper. Science, 304(5669), 422-426.
[51] Uno, T. (2011). Bond reliability under humid environment for coated copper wire and bare copper wire. Microelectronics Reliability, 51(1), 148-156.
[52] Uno, T. (2011). Enhancing bondability with coated copper bonding wire.Microelectronics Reliability, 51(1), 88-96.
[53] Martina, I., Wiesinger, R., Jembrih-Simbürger, D., Schreiner, M. (2012). Micro-Raman characterization of silver corrosion products: Instrumental set up and reference database. e-Preserv. Sci, 9, 1-8.
[54] Xu, C., Zhang, Z., Ye, Q. (2004). A novel facile method to metal sulfide (metal= Cd, Ag, Hg) nano-crystallite. Materials Letters, 58(11), 1671-1676.
[55] Tian, C., Kang, Z., Wang, E., Mao, B., Li, S., Su, Z., Xu, L. (2006). ‘One-step’controllable synthesis of Ag and Ag2S nanocrystals on a large scale. Nanotechnology, 17(22), 5681-5685.
[56] Cope, R. G., Goldsmid, H. J. (1965). Thermal switching in silver sulphide and some of its alloys. British Journal of Applied Physics, 16(10), 1501-1506.
[57] Antoku, Y., Yasuhara, K., Chiba, J., Chen, W., Okazaki, J., Maeda, N. (2013). U.S. Patent Application No. 14/142, 152.
[58] Hang, C. J., Wang, C. Q., Tian, Y. H., Mayer, M., Zhou, Y. (2008). Microstructural study of copper free air balls in thermosonic wire bonding.Microelectronic engineering, 85(8), 1815-1819.
[59] Liu, D. S., Chao, Y. C., Wang, C. H. (2004). Study of wire bonding looping formation in the electronic packaging process using the three-dimensional finite element method. Finite Elements in Analysis and Design, 40(3), 263-286.
[60] Lim, A. B., Chang, A. C., Yauw, O., Chylak, B., Gan, C. L., Chen, Z. (2014). Ultra-fine pitch palladium-coated copper wire bonding: Effect of bonding parameters. Microelectronics Reliability, 54(11), 2555-2563.
[61] Prince, A., Raynor, G. V., Evans, D. S. (1990). Phase diagrams of ternary gold alloys (Vol. 294). Woodhead Pub Ltd.
[62] Hsueh, H. W., Hung, F. Y., Lui, T. S., Chen, L. H., Chen, K. J. (2014). Intermetallic phase on the interface of Ag-Au-Pd/Al structure. Advances in Materials Science and Engineering, 1-6.
[63] Guo, R., Hang, T., Mao, D., Li, M., Qian, K., Lv, Z., Chiu, H. (2014). Behavior of intermetallics formation and evolution in Ag-8Au-3Pd alloy wire bonds. Journal of Alloys and Compounds, 588, 622-627.
[64] Uno, T., Tatsumi, K. (1999). Diffusion behavior and reliability in bonds between Au-Ag alloy and aluminum. Journal-JAPAN Institute of Metals, 63(12), 1545-1554.
[65] Cho, J. H., Oh, K. H., Rollett, A. D., Cho, J. S., Park, Y. J., Moon, J. T. (2006). Investigation of recrystallization and grain growth of copper and gold bonding wires. Metallurgical and Materials Transactions A, 37(10), 3085-3097.
[66] Pol, V. G., Grisaru, H., Gedanken, A. (2005). Coating noble metal nanocrystals (Ag, Au, Pd, and Pt) on polystyrene spheres via ultrasound irradiation. Langmuir, 21(8), 3635-3640.
[67] Okamoto, H., Massalski, T. B. (1985). The Au-Pd (Gold-Palladium) system.Bulletin of Alloy Phase Diagrams, 6(3), 229-235.
[68] Chiba, J., Teshima, S., Kobayashi, T., Antoku, Y. (2015). U.S. Patent No. 9,103,001. Washington, DC: U.S. Patent and Trademark Office.
[69] Gam, S. A., Kim, H. J., Cho, J. S., Park, Y. J., Moon, J. T., Paik, K. W. (2006). Effects of Cu and Pd addition on Au bonding wire/Al pad interfacial reactions and bond reliability. Journal of Electronic Materials, 35(11), 2048-2055.