近來來電子封裝技術在半導體產業中地位越趨重要，其中打線接合製程是最簡單且技術最成熟方式，原理為利用金屬導線連接晶片與外部接腳，形成通路傳送訊號。本研究考量不鏽鋼線材具有優異機械性質，且被廣泛應用於工程領域，因此製備出線徑為15 μm及30 μm之304L不鏽鋼細線，探討導入打線接合電子封裝技術可行性。本研究會聚焦在探討304L不鏽鋼導線顯微組織特性、通電機制及成球性，評估應用在打線接合可行性。結果顯示，直徑15 μm 與30 μm之304L不鏽鋼導線組織為長軸晶，均具優異拉伸強度與硬度。相較於30 μm不鏽鋼導線，15 μm不鏽鋼導線加工硬化效應顯著，使得拉伸強度與電阻都高於30 μm不鏽鋼導線。15 μm不鏽鋼導線具備良好電熱破壞性質，通電同步拉伸結果顯示導線於80 % FC通電下，拉伸強度維持800 MPa，延性則提升至10 %，同時擁有與原材相近拉伸韌性，展示導線於通電情形下之優異機械性質。為改善15 μm不鏽鋼導線加工硬化及延性問題，本研究探討真空退火與通電退火製程差異性，確認原始線材在真空爐中780 °C持溫15分鐘後，硬度顯著降低。再者，應用本研究公式，T = (I"．" V)/(2.3085" × " 10^(-3) ) + 25，把780 °C轉換成通電電流並進行通電退火，發現通電退火線材 (條件: 0.08安培通電5分鐘)具有軟韌化效應與高延性。線材加工儲存能與再結晶效應使15μm不鏽鋼導線電疲勞壽命達到300次；經通電退火後，基地組織受到電熱影響而具有均質效應，因此電疲勞壽命約為150次。
打線接合實驗，線材因軟韌化效應而容易放電結球，且可降低球部組織凝固偏析，放電結球高溫使頸部區域 (0-180 μm)晶粒粗大化形成熱影響區 (HAZ)，讓第一銲點動態電阻低於線材電阻，且第一銲點拉拔力低於線材，但有達到應用標準。本研究發現304L不鏽鋼線材與鋁或銅基板間界面並不會產生IMC導致電阻上升而造成接點壽命下降，具有類似同質接合特性。實驗對打線接合系統進行接點長時間通電可靠度測試，確認在長時間高電流通電下，接點電阻些微上升，界面處無因通電產生IMC現象。綜觀整體研究成果，304L不鏽鋼確實具有潛力能作為導線材料應用於電子封裝領域。

The results show that 304L stainless steel wires exhibit an elongated grain structure, high tensile strength and hardness, and favorable electrothermal failure behavior. During electrically assisted tensile testing at 80% FC, the tensile strength remained at 800 MPa while elongation increased to 10%, indicating improved ductility without sacrificing toughness. To reduce work hardening and limited ductility, the optimal annealing temperature was converted into an equivalent current using the proposed equation, followed by electrified annealing. The annealed wires (0.08 A for 5 min) showed softening, enhanced ductility, and improved microstructural homogenization, facilitating free air ball (FAB) formation and reducing solidification segregation.
During wire bonding, the high temperature during FAB formation induced grain coarsening in the neck region (0-180 μm), forming a heat-affected zone (HAZ) with lower resistance and reduced pull strength than the wire. No intermetallic compounds (IMCs) formed at the interfaces between 304L stainless steel wire and aluminum or copper substrates, preventing resistance increase and joint degradation while maintaining homogeneous bonding characteristics. Long-term current-stress tests also confirmed the absence of IMC formation under prolonged high-current conditions. Overall, 304L stainless steel shows strong potential as a wire material for electronic packaging applications.

[1]Chen, W. T., Chang, C. S., Charsky, R. S. (1990). An overview of electrical and mechanical aspects of electronic packaging. In 1990 IEEE International Symposium on Circuits and Systems (ISCAS) (pp. 2085-2094). IEEE.
[2]Zhang, Z., Wong, C. P. (2004). Recent advances in flip-chip underfill: materials, process, and reliability. IEEE transactions on advanced packaging, 27(3), 515-524.
[3]Guo, R., Gao, L., Mao, D., Li, M., Wang, X., Lv, Z., Chiu, H. (2014). Study of free air ball formation in Ag–8Au–3Pd alloy wire bonding. Microelectronics Reliability, 54(11), 2550-2554.
[4]Zhou, H., Zhang, Y., Cao, J., Su, C., Li, C., Chang, A., An, B. (2023). Research progress on bonding wire for microelectronic packaging. Micromachines, 14(2), 432.
[5]Abhijith, N. V., Kumar, D., Kalyansundaram, D. (2022). Development of single-stage TiNbMoMnFe high-entropy alloy coating on 304L stainless steel using HVOF thermal spray. Journal of Thermal Spray Technology, 31(4), 1032-1044.
[6]Chen, J., Lai, Y. S., Wang, Y. W., Kao, C. R. (2011). Investigation of growth behavior of Al–Cu intermetallic compounds in Cu wire bonding. Microelectronics reliability, 51(1), 125-129.
[7]Kim, H. G., Kim, S. M., Lee, J. Y., Choi, M. R., Choe, S. H., Kim, K. H., Ryu, J. S., Kim, S., Han, S. Z., Kim, W. Y., Lim, S. H. (2014). Microstructural evaluation of interfacial intermetallic compounds in Cu wire bonding with Al and Au pads. Acta Materialia, 64, 356-366.
[8]Chang, Y. T., Hung, F. Y., Wu, B. D. (2024). Study on material properties and copper-to-copper wire bonding of Cu-Pt-Au-Pd fine micro-alloyed wires. Journal of Electronic Materials, 53(12), 8048-8065.
[9]Tu, K. N., Chen, C., Chen, H. M. (2021). Electronic packaging science and technology. John Wiley & Sons.
[10]DLau, J. H., Erasmus, S. J., Rice, D. W. (1990). Overview of tape automated bonding technology. Circuit World, 16(2), 5-24.
[11]Shariza, S., Anand, T. J. S., Warikh, A. R. M., Chia, L. C., Yau, C. K., Huat, L. B. (2018). Bond strength evaluation of heat treated Cu-Al wire bonding. Journal of Mechanical Engineering and Sciences, 12(4), 4275-4284.
[12]Suppiah, S., Ong, N. R., Sauli, Z., Sarukunaselan, K., Alcain, J. B., Shahimin, M. M., Retnasamy, V. (2017). A short review on thermosonic flip chip bonding. In AIP conference proceedings (Vol. 1885, No. 1, p. 020266). AIP Publishing LLC.
[13]Harman, 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.
[14]Breach, C. D., Wulff, F. W. (2010). A brief review of selected aspects of the materials science of ball bonding. Microelectronics Reliability, 50(1), 1-20.
[15]Long, Y., Arndt, M., Dencker, F., Wurz, M., Twiefel, J., Wallaschek, J. (2022). Impact of surface texture on ultrasonic wire bonding process. journal of materials research and technology, 20, 1828-1838.
[16]Long, Y., Twiefel, J., Wallaschek, J. (2020). Contact mechanics and friction processes in ultrasonic wire bonding-Basic theories and experimental investigations. Journal of Sound and Vibration, 468, 115021.
[17]Ambhore, P., Mani, K., Beekley, B., Malik, N., Schjølberg-Henriksen, K., Iyer, S., Goorsky, M. S. (2018). The synergistic roles of temperature and pressure in thermo-compression bonding of Au. ECS Transactions, 86(5), 129.
[18]Huang, Y. C., Lin, Y. X., Hsiung, C. K., Hung, T. H., Chen, K. N. (2023). Cu-based thermocompression bonding and Cu/dielectric hybrid bonding for three-dimensional integrated circuits (3D ICs) application. Nanomaterials, 13(17), 2490.
[19]Breach, C. D., & Wulff, F. W. (2010). A brief review of selected aspects of the materials science of ball bonding. Microelectronics Reliability, 50(1), 1-20.
[20]Zhou, H., Chang, A., Fan, J., Cao, J., Zhang, Y., An, B., Xia, J. (2023). Effects of process parameters on bond properties of Ag-2.35 Au-0.7 Pd-0.2 Pt-0.1 cu alloy wire. Micromachines, 14(8), 1587.
[21]Cao, J., Zhang, J., Persic, J., Song, K. (2020). Effects of bonding parameters on free air ball properties and bonded strength of Ag-10Au-3.6 Pd alloy bonding wire. Micromachines, 11(8), 777.
[22]Zhou, H., Chang, A., Fan, J., Cao, J., An, B., Xia, J., Yao, J., Cui, X., Zhang, Y. (2023). Copper wire bonding: A review. Micromachines, 14(8), 1612.
[23]Pequegnat, A., Kim, H. J., Mayer, M., Zhou, Y., Persic, J., Moon, J. T. (2011). Effect of gas type and flow rate on Cu free air ball formation in thermosonic wire bonding. Microelectronics Reliability, 51(1), 43-52.
[24]Hang, C. J., Wang, C. Q., Mayer, M., Tian, Y. H., Zhou, Y., Wang, H. H. (2008). Growth behavior of Cu/Al intermetallic compounds and cracks in copper ball bonds during isothermal aging. Microelectronics reliability, 48(3), 416-424.
[25]Hung, F. Y., Lui, T. S., Chu, K. M., Tseng, Y. W. (2017). Aluminium wires have the free air balls (FABs): Electronic flame-off, fracture strength, electrical properties, and bonding characteristics of nano Zn Film Al–Si bonding wires. Metals, 7(5), 152.
[26]Wu, B. D., Hung, F. Y. (2022). The electrothermal fracture mechanism between aluminum and copper wires. Microelectronics Reliability, 139, 114819.
[27]Hu, G. (2012). Comparison of copper, silver and gold wire bonding on interconnect metallization. In 2012 13th International Conference on Electronic Packaging Technology & High Density Packaging (pp. 529-533). IEEE.
[28]Schneider-Ramelow, M., Ehrhardt, C. (2016). The reliability of wire bonding using Ag and Al. Microelectronics Reliability, 63, 336-341.
[29]Wu, B. D., Hung, F. Y., Chiu, W. S. (2025). Study of fine Au-40Ag alloy and 4N Au wires on microstructure, electrical fatigue, and corrosion resistance. Journal of Materials Science: Materials in Electronics, 36(11), 1-12.
[30]Wu, H. Y., Huang, S. R., Shih, C. H., Hsiao, L. J., Chen, H. W., Cheng, M. C., Hsu, J. C. (2022). Highly reflective silver-enhanced coating with high adhesion and sulfurization resistance for telescopes. Nanomaterials, 12(7), 1054.
[31]Xi, J., Mendoza, N., Chen, K., Yang, T., Reyes, E., Bezuk, S., Bezuk, S., Lin, L., Ke, Q., Chen, E. (2015). Evaluation of Ag wire reliability on fine pitch wire bonding. In 2015 IEEE 65th Electronic Components and Technology Conference (ECTC) (pp. 1392-1395). IEEE.
[32]Tanna, S., Pisigan, J. L., Song, W. H., Halmo, C., Persic, J., Mayer, M. (2012). Low cost Pd coated Ag bonding wire for high quality FAB in air. In 2012 IEEE 62nd Electronic Components and Technology Conference (pp. 1103-1109). IEEE.
[33]Tseng, Y. W., Hung, F. Y., Lui, T. S. (2015). Wire bonding of Au-coated Ag wire: Bondwire properties, bondability and IMCs formation. In 2015 European Microelectronics Packaging Conference (EMPC) (pp. 1-4). IEEE.
[34]Gu, B., Shen, S., Li, H. (2022). Mechanism of microweld formation and breakage during Cu–Cu wire bonding investigated by molecular dynamics simulation. Chinese Physics B, 31(1), 016101.
[35]Jaafar, N. B., Ching, E. W. L. (2016). Comparison of Au/Al, Cu/Al and Ag/Al in wirebonding assembly and IMC growth behavior. In 2016 IEEE 18th Electronics Packaging Technology Conference (EPTC) (pp. 10-12). IEEE.
[36]Lu, C. T. H. (2010). The Challenges of Copper Wire Bonding. In 2010 5th International Microsystems Packaging Assembly and Circuits Technology Conference (pp. 1-4). IEEE.
[37]Du, Y., Liu, Z. Q., Ji, H., Li, M., Wen, M. (2018). The mechanism of Pd distribution in the process of FAB formation during Pd-coated Cu wire bonding. Journal of Materials Science: Materials in Electronics, 29(16), 13774-13781.
[38]Qin, W., Anderson, T., Chang, G. (2019). Mechanism to improve the reliability of copper wire bonding with palladium-coating of the wire. Microelectronics Reliability, 99, 239-244.
[39]Chang, Y. T., Hung, F. Y., Wu, B. D. (2024). Comparison of the microstructural characteristics and the electrothermal fracture mechanism of Au-Pd-coated copper wire and Cu-Ti micro-alloyed wire. Journal of Electronic Materials, 53(4), 1695-1707.
[40]Calabretta, M., Sitta, A., Oliveri, S. M., Sequenzia, G. (2021). An experimental-numeric approach to manufacture semiconductor wafer using thick copper front metallization. International Journal on Interactive Design and Manufacturing (IJIDeM), 15(1), 117-119.
[41]Sešek, A., Makarovič, K. (2022). Metallization, material selection, and bonding of interconnections for novel ltcc and htcc power modules. Materials, 15(3), 1036.
[42]Kim, D., Yamamoto, Y., Nagao, S., Wakasugi, N., Chen, C., Suganuma, K. (2019). Measurement of heat dissipation and thermal-stability of power modules on DBC substrates with various ceramics by SiC micro-heater chip system and Ag sinter joining. Micromachines, 10(11), 745.
[43]Lu, K. H., Ryu, S. K., Zhao, Q., Zhang, X., Im, J., Huang, R., Ho, P. S. (2010). Thermal stress induced delamination of through silicon vias in 3-D interconnects. In 2010 Proceedings 60th Electronic Components and Technology Conference (ECTC) (pp. 40-45). IEEE.
[44]Zhang, M., Fei, Q., Chen, S., Yanwei, D., Chen, P., Tong, A. (2022). Protrusion of through-silicon-via (TSV) copper with double annealing processes. Journal of Electronic Materials, 51(5), 2433-2449.
[45]Kim, D., Yamamoto, Y., Nagao, S., Wakasugi, N., Chen, C., Suganuma, K. (2019). Measurement of heat dissipation and thermal-stability of power modules on DBC substrates with various ceramics by SiC micro-heater chip system and Ag sinter joining. Micromachines, 10(11), 745.
[46]Zhang, Y., Zhao, T., Yu, X., Huang, J. (2023). The Al-Fe intermetallic compounds and the atomic diffusion behavior at the interface of aluminum-steel welded joint. Metals, 13(2), 334.
[47]Wong, C. P., Bollampally, R. S. (1999). Thermal conductivity, elastic modulus, and coefficient of thermal expansion of polymer composites filled with ceramic particles for electronic packaging. Journal of applied polymer science, 74(14), 3396-3403.
[48]Antoulinakis, F., Chernin, D., Zhang, P., Lau, Y. Y. (2016). Effects of temperature dependence of electrical and thermal conductivities on the Joule heating of a one dimensional conductor. Journal of Applied Physics, 120(13).
[49]Ho, P. S., Kwok, T. (1989). Electromigration in metals. Reports on Progress in Physics, 52(3), 301.
[50]Tu, K. N. (2003). Recent advances on electromigration in very-large-scale-integration of interconnects. Journal of applied physics, 94(9), 5451-5473.
[51]Chuang, H. C., Hung, F. Y., Lui, T. S., Chen, L. H. (2011). Effect of the twins on mechanical properties of AISI 304 stainless steel wire using electrical current method. Materials transactions, 52(1), 25-30.
[52]Hung, F. Y., Lui, T. S., Chen, L. H., Wang, Y. T. (2007). Recrystallization and fracture characteristics of thin copper wire. Journal of materials science, 42(14), 5476-5482.
[53]Xu, Q., Zhu, J., Zong, Y., Liu, L., Zhu, X., Zhang, F., Luan, B. (2021). Effect of drawing and annealing on the microstructure and mechanical properties of 304 austenitic stainless steel wire. Materials Research Express, 8(12), 126530.
[54]Milad, M., Zreiba, N., Elhalouani, F., Baradai, C. (2008). The effect of cold work on structure and properties of AISI 304 stainless steel. Journal of materials processing technology, 203(1-3), 80-85.
[55]Pham, H. T., Iwamoto, T. (2018). An evaluation of fracture properties of type-304 austenitic stainless steel at high deformation rate using the small punch test. International Journal of Mechanical Sciences, 144, 249-261.
[56]Hu, G. (2012). Comparison of copper, silver and gold wire bonding on interconnect metallization. In 2012 13th International Conference on Electronic Packaging Technology & High Density Packaging (pp. 529-533). IEEE.
[57]Liu, W. Q., Lian, J. H. (2021). Stress-state dependence of dynamic strain aging: Thermal hardening and blue brittleness. International Journal of Minerals, Metallurgy and Materials, 28(5), 854-866.
[58]Konovalenko, I., Maruschak, P., Brezinová, J., Brezina, J. (2019). Morphological characteristics of dimples of ductile fracture of VT23M titanium alloy and identification of dimples on fractograms of different scale. Materials, 12(13), 2051.
[59]Bidulský, R., Bidulská, J., Gobber, F. S., Kvačkaj, T., Petroušek, P., Actis-Grande, M., Weiss, K., Manfredi, D. (2020). Case study of the tensile fracture investigation of additive manufactured austenitic stainless steels treated at cryogenic conditions. Materials, 13(15), 3328.
[60]Choi, J. Y., Jin, W. (1997). Strain induced martensite formation and its effect on strain hardening behavior in the cold drawn 304 austenitic stainless steels. Scripta Materialia, 36(1), 99-104.
[61]Zhou, Z., Wang, S., Li, J., Li, Y., Wu, X., Zhu, Y. (2020). Hardening after annealing in nanostructured 316L stainless steel. Nano Materials Science, 2(1), 80-82.
[62]Balluffi, R. W., Allen, S. M., Carter, W. C. (2005). Kinetics of materials. John Wiley & Sons.
[63]Furushima, T., Imagawa, Y., Manabe, K. I., Sakai, T. (2015). Effects of oxidation and surface roughening on drawing limit in dieless drawing process of SUS304 stainless steel microtubes. Journal of Materials Processing Technology, 223, 186-192.
[64]Hwang, Y. M., Liu, H. H. (2019). Formability analysis and oxidation layer effects in dieless drawing of stainless steel wires. Metals, 9(8), 828.
[65]Wu, W., Brongersma, S. H., Van Hove, M., Maex, K. (2004). Influence of surface and grain-boundary scattering on the resistivity of copper in reduced dimensions. Applied physics letters, 84(15), 2838-2840.
[66]Dong, L., Yang, F., Yu, T., Zhang, N., Zhou, X., Xie, Z., Fang, F. (2023). Contribution of grain boundary to strength and electrical conductivity of annealed copper wires. journal of materials research and technology, 26, 1459-1468.
[67]Feng, Z. (2015). The Lattice Parameter of Gamma Iron and Iron-Chromium Alloys (Master's thesis, Case Western Reserve University).
[68]Abd Rashid, M. W., Gakim, M., Rosli, Z. M., Azam, M. A. (2012). Formation of Cr23C6 during the sensitization of AISI 304 stainless steel and its effect to pitting corrosion. International Journal of Electrochemical Science, 7(10), 9465-9477.
[69]He, S., Shang, H., Fernández-Caballero, A., Warren, A. D., Knowles, D. M., Flewitt, P. E. J., Martin, T. L. (2021). The role of grain boundary ferrite evolution and thermal aging on creep cavitation of type 316H austenitic stainless steel. Materials Science and Engineering: A, 807, 140859.
[70]Fu, J. W., Yang, Y. S., Guo, J. J., Tong, W. H. (2008). Effect of cooling rate on solidification microstructures in AISI 304 stainless steel. Materials Science and Technology, 24(8), 941-944.
[71]Ma, J. C., Yang, Y. S., Tong, W. H., Fang, Y., Yu, Y., Hu, Z. Q. (2007). Microstructural evolution in AISI 304 stainless steel during directional solidification and subsequent solid-state transformation. Materials Science and Engineering: A, 444(1-2), 64-68.
[72]Fu, J. W., Yang, Y. S., Guo, J. J., Ma, J. C., Tong, W. H. (2009). Microstructure evolution in AISI 304 stainless steel during near rapid directional solidification. Materials Science and Technology, 25(8), 1013-1016.
[73]Huang, F. X., Zhang, J. M. (2008). In situ observation of solidification process of AISI 304 austenitic stainless steel. Journal of iron and steel research, International, 15(6), 78-82.
[74]Hung, F. Y., Lui, T. S., Chu, K. M., Tseng, Y. W. (2017). Aluminium wires have the free air balls (FABs): Electronic flame-off, fracture strength, electrical properties, and bonding characteristics of nano Zn Film Al–Si bonding wires. Metals, 7(5), 152.
[75]Hsu, H. C., Chang, W. Y., Yeh, C. L., Lai, Y. S. (2011). Characteristic of copper wire and transient analysis on wirebonding process. Microelectronics Reliability, 51(1), 179-186.
[76]Mukherjee, T., Wei, H. L., De, A., DebRoy, T. (2018). Heat and fluid flow in additive manufacturing–Part II: Powder bed fusion of stainless steel, and titanium, nickel and aluminum base alloys. Computational Materials Science, 150, 369-380.
[77]Ode, M., Kim, S. G., Kim, W. T., Suzuki, T. (2001). Numerical prediction of the secondary dendrite arm spacing using a phase-field model. ISIJ international, 41(4), 345-349.
[78]Cui, A., Wang, X., Cui, Y. (2024). Multiscale modelling of precipitation hardening: a review. Journal of Materials Science: Materials Theory, 8(1), 13.
[79]Reis, B. P., França, R. P., Spim, J. A., Garcia, A., Da Costa, E. M., Santos, C. A. (2013). The effects of dendritic arm spacing (as-cast) and aging time (solution heat-treated) of Al–Cu alloy on hardness. Journal of Alloys and Compounds, 549, 324-335.
[80]Kurz, W., Fisher, D., Rappaz, M. (2023). Fundamentals of solidification.
[81]Cao, J., Zhang, J., Persic, J., Song, K. (2020). Effects of bonding parameters on free air ball properties and bonded strength of Ag-10Au-3.6 Pd alloy bonding wire. Micromachines, 11(8), 777.
[82]Gomes, J., Mayer, M., Lin, B. (2015). Development of a fast method for optimization of Au ball bond process. Microelectronics Reliability, 55(3-4), 602-607.