銀為電及熱的良導體，價格雖比銅來得高，卻比金來得低廉，亦無銅線易氧化及強度過高的問題，在打線接合製程中，是一種新穎的線材材料。本研究以23μm銀導線於線材退火、放電結球、打線接合及通電試驗所造成的微觀組織及拉伸性質變化做探討。
　　本研究採用純銀線材，在250oC的溫度下進行30分鐘的真空退火處理後，線材受到再結晶之影響，其微硬度值下降到Hv53±2，約略與金線的微硬度相當，其拉伸性質亦達到一個較為穩定的狀態。
　　對退火前後的線材分別做放電結球，其FAB之橫截面中皆包含3~4顆柱狀晶，EFO過程亦於線材的部分生成熱影響區。藉由微觀組織及微硬度值之觀察，顯示退火前後的線材於放電結球後，會具有不同長短的熱影響區，分別是420μm與220μm。受到放電結球生成熱影響區的影響，強度較線材其他位置低，使得應變集中於熱影響區，導致拉伸性質改變。
　　本研究使用退火後之銀線進行打線接合製程，採用兩種不同鋁基板，分別為鋁塊及500nm的鋁膜。通電前進行拉力測試的結果顯示兩種基板的銀線都在HAZ斷裂。經過通電之後，新形成的熱影響區造成斷裂位置移到整個線材試片的中間位置。兩種基板的接合狀況，鋁膜試片較鋁塊基板增加了斷裂在接合界面的可能性。

　　Silver is a novel wire material of wire bonding process because its excellent electrical and thermal properties, it’s more expensive than copper but cheaper than gold, and it’s lower hardness and hard to oxidative compared to copper. In this study, the effects of the microstrctures and tensile properties after annealing, EFO, wire bonding and electrical current test of the 23μm silver wire are studied.
　　After the silver wires are annealed at 250℃ for 30minutes, the microhardness decreases to Hv 53±2 which is similar to gold and the tensile properties are steady because of recrystallization,.
　　After the EFO process, there are 3~4 columnar grains in the FAB and HAZ in the wire whether the sample is annealed or not. According to the results of the microstructure and the microhardness, the lengths of HAZ in the as-drawn wire and annealed wire are 420μm and 220μm respectively. Due to the fact of forming HAZ, the strength is the lowest and strain concentration in this area, leading to the change of the tensile properties.
　　In this study, I use two different Al subtrates, Al-bulk and Al-500nm thin film, as experiment’s bonding pads. Before the current test, the fracture of silver wire mainly occurs in the HAZ during the pull tests. After the current test, the fracture positions has shifted to the middle of new HAZ which is formed by the current test. Among the two substrates, Al-500nm thin film is more likely to fracture at the contact interface.

1. T. C. Wei and A. R. Daud, "Mechanical and Electrical Properties of Au-Al and Cu-Al Intermetallics Layer at Wire Bonding Interface", Journal of Electronic Packaging, Vol. 125 (2003), pp. 617-620.
2. G. G. Harman, "Technical Introduction to the Second Edition", in Wire Bonding in Microelectronics: Materials, Processes, Reliability, and Yield. 1997, McGraw-Hill: New York.
3. S. Murali, N. Srikanth and C. J. Vath, "Grains, Deformation Substructures, and Slip Bands Observed in Thermosonic Copper Ball Bonding", Materials Characterization, Vol. 50 (2003), pp. 39-50.
4. Y. Tian, C. Wang, I. Lum, M. Mayer, J. P. Jung and Y. Zhou, "Investigation of Ultrasonic Copper Wire Wedge Bonding on Au/Ni Plated Cu Substrates at Ambient Temperature", Journal of Materials Processing Technology, Vol. 208 (2008), pp. 179-186.
5. J. H. Lau, "Chip on Board Technologies for Multichip Modules". 1994, New York: Van Nostrand Reinhold.
6. A. Shah, H. Gaul, M. Schneider-Ramelow, H. Reichl, M. Mayer and Y. Zhou, "Ultrasonic Friction Power During Al Wire Wedge-Wedge Bonding", Journal of Applied Physics, Vol. 106 (2009).
7. O. L. Anderson, H. Christensen and P. Andreatch, "Technique for Connecting Electrical Leads to Semiconductors", Journal of Applied Physics, Vol. 28 (1957), pp. 923-923.
8. B. Langenecker, "Effects of Ultrasound on Deformation Characteristics of Metals", IEEE Transactions on Sonics and Ultrasonics, Vol. 13 (1966), pp. 1-8.
9. 林宜璋，「不同退火條件之銅導線經放電結球前後之機械性質與織構分析」，材料科學及工程學系研究所，碩士論文，2007：國立成功大學。
10. S. Kaimori, T. Nonaka and A. Mizoguchi, "The Development of Cu Bonding Wire with Oxidation-Resistant Metal Coating", IEEE Transactions on Advanced Packaging, Vol. 29 (2006), pp. 227-231.
11. F. Wulff, C. D. Breach and K. Dittmer, "Crystallographic Texture of Drawn Gold Bonding Wires Using Electron Backscattered Diffraction (EBSD)", Journal of Materials Science Letters, Vol. 22 (2003), pp. 1373-1376.
12. C. D. Breach and F. Wulff, "New Observations on Intermetallic Compound Formation in Gold Ball Bonds: General Growth Patterns and Identification of Two Forms of Au4al", Microelectronics Reliability, Vol. 44 (2004), pp. 973-981.
13. M. Sheaffer, L. Levine and B. Schlain, "Optimizing the Wire-Bonding Process for Copper Ball Bonding, Using Classic Experimental Designs", Components, Hybrids, and Manufacturing Technology, IEEE Transactions on, Vol. 10 (1987), pp. 321-326.
14. K. Toyozawa, K. Fujita, S. Minamide and T. Maeda, "Development of Copper Wire Bonding Application Technology", Components, Hybrids, and Manufacturing Technology, IEEE Transactions on, Vol. 13 (1990), pp. 667-672.
15. Z. W. Zhong, H. M. Ho, Y. C. Tan, W. C. Tan, H. M. Goh, B. H. Toh and J. Tan, "Study of Factors Affecting the Hardness of Ball Bonds in Copper Wire Bonding", Microelectronic Engineering, Vol. 84 (2007), pp. 368-374.
16. S. J. Hu, G. E. Lim, T. L. Lim and K. P. Foong, "Study of Temperature Parameter on the Thermosonic Gold Wire Bonding of High-Speed CMOS", Components, Hybrids, and Manufacturing Technology, IEEE Transactions on, Vol. 14 (1991), pp. 855-858.
17. C. J. Hang, W. H. Song, I. Lum, M. Mayer, Y. Zhou, C. Q. Wang, J. T. Moon and J. Persic, "Effect of Electronic Flame Off Parameters on Copper Bonding Wire: Free-Air Ball Deformability, Heat Affected Zone Length, Heat Affected Zone Breaking Force", Microelectronic Engineering, Vol. 86 (2009), pp. 2094-2103.
18. S. Murali, N. Srikanth and C. J. Vath, "An Analysis of Intermetallics Formation of Gold and Copper Ball Bonding on Thermal Aging", Materials Research Bulletin, Vol. 38 (2003), pp. 637-646.
19. H. J. Kim, J. Y. Lee, K. W. Paik, K. W. Koh, J. H. Won, S. Y. Choe, J. Lee, J. T. Moon and Y. J. Park, "Effects of Cu/Al Intermetallic Compound (IMC) on Copper Wire and Aluminum Pad Bondability", IEEE Transactions on Components and Packaging Technologies, Vol. 26 (2003), pp. 367-374.
20. C. J. Hang, C. Q. Wang, M. Mayer, Y. H. Tian, Y. Zhou and H. H. Wang, "Growth Behavior of Cu/Al Intermetallic Compounds and Cracks in Copper Ball Bonds During Isothermal Aging", Microelectronics Reliability, Vol. 48 (2008), pp. 416-424.
21. H. C. William, H. Baker, D. Benjamin, P. M. Unterweiser, C. W. Kirkpatrick, V. Knoll and K. Nieman, "Metals Handbook - Properties and Selection : Nonferrous Alloys and Pure Metals", 9th ed. Vol. 2. 1979, Metals Park, Ohio: American Society for Metals.
22. T. M. Jeong, S. H. June, S. C. Jong and H. K. Seong, "New Materials for Bonding Wire", in SEMICON Singapore. 2008. Singapore.
23. G. G. Harman, "Ultrasonic Bonding Systems and Techonologies", in Wire Bonding in Microelectronics: Materials, Processes, Reliability, and Yield. 1997, McGraw-Hill: New York. p. 11-42.
24. I. Wei Qin, "Wire Bonding Tutorial", Advanced Packaging, Vol. 14 (2005), pp. 42-45.
25. 陳博彥，「微細銅導線放電結球特性與打線接合強度要因探討」，材料科學及工程學系研究所，碩士論文，2008：國立成功大學。
26. 黃翊婷，「15μm級放電結球及打線接合微細銅導線之拉伸斷線特性探討」，材料科學及工程學系研究所，碩士論文，2009：國立成功大學。
27. C. J. Hang, C. Q. Wang, Y. H. Tian, M. Mayer and Y. Zhou, "Microstructural Study of Copper Free Air Balls in Thermosonic Wire Bonding", Microelectronic Engineering, Vol. 85 (2008), pp. 1815-1819.
28. 王元亭，「放電結球細微銅導線抗拉強度之韋伯解析研究」，材料科學及工程學系研究所，碩士論文，2005：國立成功大學。
29. J. D. Verhoeven, "Fundamentals of Physical Metallurgy". 1975, New York: John Wiley & Sons. P 244.
30. 陳信安，「微細銅導線氧化微觀組織及界面接合通電特性研究」，材料科學及工程學系研究所，2010(進行中研究)：國立成功大學。