近年來將擁有優良的導電及導熱性質的奈米粒子應用於微電子元件上，為現今可撓式電子產品封裝趨勢。其中奈米銀膠最具發展性，因其具低溫燒結特性及低成本優勢且銀本身為良好的導熱及導電材料所致。然而，奈米銀膠接合技術常需要高溫高壓才能實現，而高壓明顯限制生產產量及增加製程成本，高溫則具損壞晶片的缺點。本論文係以發展奈米銀膠的低溫低壓接合技術為目的，將奈米銀膠置於大氣環境下以150-250℃ 的溫度範圍及5MPa荷重發展及研究一步驟的直接接合機制及二步驟的先燒結後接合的接合機制。在180℃的環境下燒結後，奈米銀膠的電阻率及硬度有明顯的改善。接合後探討其燒結奈米銀膠接合面及銅膜與燒結奈米銀膠的介面結構變化。另外，其對應的剪力強度也一併探討。結果顯示，二步驟製程中燒結奈米銀膠的電阻率和硬度在燒結溫度180℃以上有明顯改善，另外其接合面在最低接合溫度150℃下結合良好且其剪切強度在250℃以下的低溫皆高於銅銀介面。而一步驟直接接合製程中的奈米銀膠接合面也能在最低接合溫度150℃下成功接合。此外，可靠度表現則由溫度循環測試結果證實無論是燒結奈米銀膠接合面亦或是銅膜與燒結奈米銀膠的介面結構變化都不受影響。在此結果基礎，奈米銀膠的低溫接合製程極具發展潛力且在分別成功實現在一步驟的一小時150℃直接接合製程以及兩步驟的180℃燒結過後在150℃接合製程。

Ag nanoparticles paste is a promising candidate for bonding technology in flexible electronics packaging because Ag possesses excellent thermal and electrical performances, and Ag nanoparticles paste has a reasonable price and low temperature sintering capability. However, bonding technology usually requires high temperature and high pressures during bonding process, which may damage chips and increase the processing cost. In this study, low-temperature bonding process using sintered silver nanoparticles paste for die attachment application was developed. The mechanism of the one-step and two-step process was evaluated in air at temperature of 150-250℃ under 5 MPa, respectively. The resistivity and hardness of the sintered Ag layer significantly improved when sintered above 180℃. The microstructural evolution in the Ag nanoparticles paste during the bonding process, and the bonding interface over various bonding temperatures was characterized. The corresponding bonding strength was also analyzed. The results revealed that the bonding interface of the sintered Ag layers of the joints produced by two steps process was well bonded at the lowest temperature of 150℃ and the shear strength of sintered Ag layers at low bonding temperature was stronger than that of the interface of Cu/Ag. For one step process, the joints can successfully achieved at the lowest temperature of 150℃. In addition, thermal cycle test was performed and the results of that revealed the microstructure evolution of the joints was unaffected after thermal cycle test. Based on the results, the joints using Ag nanoparticles at low-temperature under low-pressure can be achieved on two step process of sintering at 180℃ and bonding at 150℃ or one step of bonding directly at 150℃.

[1] R. W. J. J.B. Casady, "Status of silicon carbide (SiC) as a wide-bandgap semiconductor for high-temperature applications: a review," Solid-State Electronics, vol. 39, no. 10, pp. 1409-1422, 1996.
[2] R. S. O. P.G. Neudeck, L.Y. Chen, "High-temperature electronics - a role for wide bandgap semiconductors," IEEE, vol. 90, pp. 1065-1076, 2002.
[3] F. R. S.J. Pearton, A.P. Zhang, K.P. Lee, "Fabrication and performance of GaN electronic devices," Materials Science and Engineering, vol. 30, pp. 55-212, 2000.
[4] A. K. Panigrahy and K.-N. Chen, "Low Temperature Cu–Cu Bonding Technology in Three-Dimensional Integration: An Extensive Review," Journal of Electronic Packaging, vol. 140, no. 1, 2018.
[5] Y.-S. Tang, Y.-J. Chang, and K.-N. Chen, "Wafer-level Cu–Cu bonding technology," Microelectronics Reliability, vol. 52, no. 2, pp. 312-320, 2012.
[6] R. Khazaka, L. Mendizabal, and D. Henry, "Review on Joint Shear Strength of Nano-Silver Paste and Its Long-Term High Temperature Reliability," (in English), Journal of Electronic Materials, vol. 43, no. 7, pp. 2459-2466, 2014.
[7] G. L. Allen, R. A. Bayles, W. W. Gile, and W. A. Jesser, "Small particle melting of pure metals," (in English), Thin Solid Films, vol. 144, no. 2, pp. 297-308, 1986.
[8] C.-H. Tsou, K.-N. Liu, H.-T. Lin, and F.-Y. Ouyang, "Electrochemical Migration of Fine-Pitch Nanopaste Ag Interconnects," (in English), Journal of Electronic Materials, vol. 45, no. 12, pp. 6123-6129, 2016.
[9] J. Li, C. M. Johnson, C. Buttay, W. Sabbah, and S. Azzopardi, "Bonding strength of multiple SiC die attachment prepared by sintering of Ag nanoparticles," Journal of Materials Processing Technology, vol. 215, pp. 299-308, 2015.
[10] P. Peng, A. Hu, A. P. Gerlich, G. Zou, L. Liu, and Y. N. Zhou, "Joining of Silver Nanomaterials at Low Temperatures: Processes, Properties, and Applications," ACS Appl Mater Interfaces, vol. 7, no. 23, pp. 12597-618, 2015.
[11] W.-H. Li et al., "Low-temperature Cu-to-Cu bonding using silver nanoparticles stabilised by saturated dodecanoic acid," Materials Science and Engineering: A, vol. 613, pp. 372-378, 2014.
[12] A. Hu et al., "Low temperature sintering of Ag nanoparticles for flexible electronics packaging," Applied Physics Letters, vol. 97, no. 15, 2010.
[13] M. J. M. Jakubowska, K. Kiełbasinski, A. Młożniak, "New conductive thick-film paste based on silver nanopowder for high power and high temperature applications," IEEE, vol. 51, no. 7, pp. 1235-1240, 2011.
[14] E. Ide, S. Angata, A. Hirose, and K. Kobayashi, "Metal-metal bonding process using Ag metallo-organic nanoparticles," Acta Materialia, vol. 53, no. 8, pp. 2385-2393, 2005.
[15] S. Y. S. K. Volkman, T. Bakhishev, K. Puntambekar, V. Subramanian, M.F. Toney, "Mechanistic studies on sintering of silver nanoparticles," Chemistry of Materials, vol. 23, no. 20, pp. 4634-4640, 2011.
[16] P. Peng et al., "Joining of silver nanomaterials at low temperatures: processes, properties, and applications," ACS Applied Materials & Interfaces, vol. 7, no. 23, pp. 12597-12618, 2015.
[17] J. R. Sambles, L. Skinner, N. J. P. o. t. R. S. o. L. A. M. Lisgarten, and P. Sciences, "An electron microscope study of evaporating small particles: the Kelvin equation for liquid lead and the mean surface energy of solid silver," Mathematical and Physical Sciences, vol. 318, no. 1535, pp. 507-522, 1970.
[18] K. Hayashi and H. J. M. t. Etoh, JIM, "Pressure sintering of iron, cobalt, nickel and copper ultrafine powders and the crystal grain size and hardness of the compacts," Materials transactions, vol. 30, no. 11, pp. 925-931, 1989.
[19] J. D. Hansen, R. P. Rusin, M. H. Teng, and D. L. J. J. o. t. A. C. S. Johnson, "Combined‐Stage Sintering Model," Journal of the American Ceramic Society, vol. 75, no. 5, pp. 1129-1135, 1992.
[20] D. Owen and A. J. N. m. Chokshi, "An evaluation of the densification characteristics of nanocrystalline materials," Nanostructured Materials, vol. 2, no. 2, pp. 181-187, 1993.
[21] Y. J. Moon, H. Kang, K. Kang, and S.-J. J. J. o. E. M. Moon, "Effect of thickness on surface morphology of silver nanoparticle layer during furnace sintering," Journal of Electronic Materials, vol. 44, no. 4, pp. 1192-1199, 2015.
[22] J. Groza and R. J. N. m. Dowding, "Nanoparticulate materials densification," Nanostructured Materials, vol. 7, no. 7, pp. 749-768, 1996.
[23] D. R. Lide, CRC handbook of chemistry and physics. CRC press, 2004.
[24] Y. Morisada, T. Nagaoka, M. Fukusumi, Y. Kashiwagi, M. Yamamoto, and M. J. J. o. e. m. Nakamoto, "A low-temperature bonding process using mixed Cu–Ag nanoparticles," Journal of Electronic Materials, vol. 39, no. 8, pp. 1283-1288, 2010.
[25] T. Morita, E. Ide, Y. Yasuda, A. Hirose, and K. Kobayashi, "Study of Bonding Technology Using Silver Nanoparticles," (in English), Japanese Journal of Applied Physics, vol. 47, no. 8, pp. 6615-6622, 2008.
[26] A. Sawatzky and F. E. Jaumot, "Diffusion of the Elements of the Ib and Iib Subgroups in Silver," (in English), Transactions of the American Institute of Mining and Metallurgical Engineers, vol. 209, no. 10, pp. 1207-1210, 1957.
[27] D. B. Williams and C. B. Carter, "The transmission electron microscope," in Transmission electron microscopy: Springer, 1996, pp. 3-17.
[28] F. Le Henaff, S. Azzopardi, J. Y. Deletage, E. Woirgard, S. Bontemps, and J. Joguet, "A preliminary study on the thermal and mechanical performances of sintered nano-scale silver die-attach technology depending on the substrate metallization," Microelectronics Reliability, vol. 52, no. 9-10, pp. 2321-2325, 2012.
[29] J. Eggers, "Coalescence of spheres by surface diffusion," (in English), Physical Review Letters, vol. 80, no. 12, pp. 2634-2637, 1998.
[30] J. E. Morris, "Nanoparticle properties," in Nanopackaging: Springer, 2018, pp. 201-217.
[31] M. J. Mayo, "Processing of nanocrystalline ceramics from ultrafine particles," (in English), International Materials Reviews, vol. 41, no. 3, pp. 85-115, 1996.
[32] P. Zeng, S. Zajac, P. C. Clapp, and J. A. Rifkin, "Nanoparticle sintering simulations," (in English), Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, vol. 252, no. 2, pp. 301-306, 1998.
[33] L. Ding, R. L. Davidchack, and J. Pan, "A molecular dynamics study of sintering between nanoparticles," Computational Materials Science, vol. 45, no. 2, pp. 247-256, 2009.
[34] Z. Z. Fang, H. Wang, and V. Kumar, "Coarsening, densification, and grain growth during sintering of nano-sized powders—A perspective," International Journal of Refractory Metals and Hard Materials, vol. 62, pp. 110-117, 2017.
[35] H. T. Wang, Z. Z. Fang, and K. S. Hwang, "Kinetics of Initial Coarsening During Sintering of Nanosized Powders," (in English), Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science, vol. 42a, no. 11, pp. 3534-3542, 2011.
[36] H. Wang and Z. J. J. o. t. A. C. S. Zak Fang, "Kinetic Analysis of Densification Behavior of Nano‐sized Tungsten Powder," Journal of the American Ceramic Society, vol. 95, no. 8, pp. 2458-2464, 2012.
[37] M. L. Allen et al., "Electrical sintering of nanoparticle structures," Nanotechnology, vol. 19, no. 17, p. 175201, 2008.
[38] A. Zuruzi and K. S. Siow, "Electrical Conductivity of Porous Silver Made from Sintered Nanoparticles," (in English), Electronic Materials Letters, vol. 11, no. 2, pp. 308-314, 2015.
[39] J. C. Kim, K. H. Auh, and D. M. Martin, "Multi-level particle packing model of ceramic agglomerates," (in English), Modelling and Simulation in Materials Science and Engineering, vol. 8, no. 2, pp. 159-168, 2000.
[40] P. Bowen and C. Carry, "From powders to sintered pieces: forming, transformations and sintering of nanostructured ceramic oxides," (in English), Powder Technology, vol. 128, no. 2-3, pp. 248-255, 2002.
[41] A. J. p. s. s. Bukaluk, "AES depth profile studies of interdiffusion in the Ag Cu bilayer and multilayer thin films," vol. 118, no. 1, pp. 99-107, 1990.