中溫型碲化鍺熱電材料具有優異的熱電傳輸性質，具有模組化發展的潛力。而高效能的熱電模組除了材料本身的高zT值外，也需要在熱電接點和金屬電極之間引入一機械強度高且能在高溫運作條件下能保持穩定的接合層以提升整體模組可靠度。在本研究中，首先利用無電鍍沉積法所沉積的薄膜具有良好附著性的特點，在銅電極及熱電基板表面依次沉積Ni(P)擴散阻障層和Ag接合層，且在Ni(P)和Ag層之間引入無電鍍Pd的金屬層以提高擴散阻障層與接合層之間的附著性使其強度進一步提高。隨後利用銀薄膜直接接合的技術，在大氣環境中於250°C ~ 325°C和80 MPa壓力的條件下，將完成表面處理的碲化鍺熱電材料與銅電極之間進行熱壓接合。確認界面微結構之後接著進行接面機械強度推力測試，結果顯示熱電材料/銅電極接面的機械強度會隨著接合溫度上升而有明顯的增加，在325°C的接合溫度下達到最高14.8 MPa的平均剪應力強度。經過破裂面的分析後，發現斷裂面有接近97%的面積比例出現在熱電材料內部，顯示銀-銀對接所組成的接合層以及化鎳鈀銀的複合層結構在模組當中的機械強度比起碲化鍺材料本身所能承受的應力更高，在模組遭受外力破壞之後接合層仍能保持穩定而不發生斷裂，顯示銀接合層具有良好的接合強度表現。

GeTe-based compounds exhibit promising thermoelectric properties in middle-high temperature regime. A functional thermoelectric module requires an appropriate bonding layer between thermoelectric legs and metal electrode. This conductive bonding layer must have good mechanical strength to sustain high temperature operation conditions. In this study, an Ag-to-Ag direct bonding technology is developed for joining Ge0.87Pb0.13Te thermoelectric legs with copper electrode. A Ni(P) diffusion barrier and an Ag bonding layer were sequentially deposited on both Cu electrode and Ge0.87Pb0.13Te thermoelectric legs via electroless-plating method. An electroless-Pd layer was introduced between Ni(P) and Ag layer to improve the adhesion between Ni(P) and Ag bonding layers. The resulting structure was subsequently subjected to thermo-compression bonding in ambient atmosphere at the temperature ranging from 250°C to 325°C under a pressure of 80 MPa. The cross-sectional SEM image shows a high quality bonding interface when sample were bonded at 325°C, The fracture shear strength can reaches 14.8 MPa in average. Basically, the bonding strength increases with increasing bonding temperature for the sample tested. By examining the fracture surface, there is 97% fracuture surface inside the thermoelectirc material. It indicates that the Ni(P)/Pd/Ag bonding layer strength is superior to Ge0.87Pb0.13Te fracture strength.

摘要 I
Abstract II
致謝 III
目錄 IV
圖目錄 VI
表目錄 IX
一、前言 1
1.1 研究背景 1
1.2 無電鍍技術 3
1.2.1 無電鍍原理 3
1.2.2 無電鍍溶液 3
1.3 研究動機 5
二、文獻回顧 6
2.1 碲化鍺系化合物 6
2.2 固液擴散接合 8
2.2.1 接合方法與原理 8
2.2.2 擴散接合方法應用於中溫熱電模組 9
2.3 銀薄膜直接接合技術 12
2.3.1 金屬薄膜接合簡介 12
2.3.2 低外加壓力下的銀對銀接合 13
2.3.3 氧化銀分解 15
2.3.4 高接合壓力下的銀接合 17
2.4 無電鍍鎳磷擴散阻障層 21
2.4.1 對銅原子之擴散阻障能力 21
2.4.2 與熱電材料的界面反應 24
三、實驗流程與分析方法 26
3.1 熱電材料製備 26
3.2 無電鍍Ni(P)/Ag鍍層 28
3.2.1 製備Cu/Ni(P)系統 28
3.2.2 製備GPT/Ni(P)系統 28
3.2.3 無電鍍Ag接合層 29
3.3 接合實驗設置與分析 30
3.3.1 接合實驗設計 30
3.3.2 反應後試片處理、觀察及分析 31
3.3.3 推力測試 32
四、結果與討論 33
4.1 無電鍍Ni(P)的前處理及析鍍 33
4.1.1 鍍製前處理及鍍層性質 33
4.1.2 無電鍍Ni(P)層鍍率分析 36
4.2 無電鍍Pd/Ag接合層 38
4.2.1 無電鍍Pd層對Ni(P)/Ag界面的影響 38
4.2.2 無電鍍Ag層鍍率及反應機制 42
4.2.3 無電鍍Ni(P)/Pd/Ag結構在熱電基材上之特性 46
4.3 銀對銀直接接合研究 49
4.3.1 外加壓力對接合性質的影響 49
4.3.2 銀對銀直接接合強度及微結構 52
4.3.3 破裂面分析 54
4.3.4 模組接合強度比較 58
五、結論 59
六、參考文獻 60

[1] H. S. Kim, W. Liu, G. Chen, C.-W. Chu, and Z. Ren, "Relationship between thermoelectric figure of merit and energy conversion efficiency," Proceedings of the National Academy of Sciences, vol. 112, no. 27, pp. 8205-8210, 2015.
[2] S. Perumal, S. Roychowdhury, and K. Biswas, "High performance thermoelectric materials and devices based on GeTe," Journal of Materials Chemistry C, vol. 4, no. 32, pp. 7520-7536, 2016.
[3] A. K. Yadav, S. Singh, and G. Gupta, "Solar Air-Conditioning: Design for a Compressor-Less System using Peltier Effect," International Journal, vol. 2, no. 2, pp. 429-432, 2014.
[4] L. Benabou, V. Etgens, and Q. B. Tao, "Finite element analysis of the effect of process-induced voids on the fatigue lifetime of a lead-free solder joint under thermal cycling," Microelectronics Reliability, vol. 65, pp. 243-254, 2016.
[5] B. J. Hwang and S. H. Lin, "Reaction mechanism of electroless deposition: observations of morphology evolution during nucleation and growth via tapping mode AFM," Journal of the Electrochemical Society, vol. 142, no. 11, p. 3749, 1995.
[6] H. Kind, A. M. Bittner, O. Cavalleri, K. Kern, and T. Greber, "Electroless deposition of metal nanoislands on aminothiolate-functionalized Au (111) electrodes," The Journal of Physical Chemistry B, vol. 102, no. 39, pp. 7582-7589, 1998.
[7] K. H. Krishnan, S. John, K. Srinivasan, J. Praveen, M. Ganesan, and P. Kavimani, "An overall aspect of electroless Ni-P depositions—A review article," Metallurgical and materials transactions A, vol. 37, no. 6, pp. 1917-1926, 2006.
[8] A. Vaskelis, A. Jagminiene, R. Juškénas, E. Matulionis, and E. Norkus, "Structure of electroless silver coatings obtained using cobalt (II) as reducing agent," Surface and Coatings technology, vol. 82, no. 1-2, pp. 165-168, 1996.
[9] W.-C. Lin, Y.-S. Li, and A. T. Wu, "Study of diffusion barrier for solder/n-type Bi2Te3 and bonding strength for p-and n-type thermoelectric modules," Journal of Electronic Materials, vol. 47, no. 1, pp. 148-154, 2018.
[10] H.-C. Hsieh, A. T. Wu "Electroless Co-P diffusion barrier for n-PbTe thermoelectric material," Journal of Alloys and Compounds, vol. 728, pp. 1023-1029, 2017.
[11] J.-W. Yoon, B.-I. Noh, and S.-B. Jung, "Comparative study of ENIG and ENEPIG as surface finishes for a Sn-Ag-Cu solder joint," Journal of electronic materials, vol. 40, no. 9, pp. 1950-1955, 2011.
[12] Q. Bui and S. Jung, "Characterization of low speed shear test reliability of Sn–1.0 Ag–XCe/ENEPIG solder joint," Journal of alloys and compounds, vol. 560, pp. 54-61, 2013.
[13] C.-F. Tseng and J.-G. Duh, "Correlation between microstructure evolution and mechanical strength in the Sn–3.0 Ag–0.5 Cu/ENEPIG solder joint," Materials Science and Engineering: A, vol. 580, pp. 169-174, 2013.
[14] H. Okamoto, "Ge-Te (germanium-tellurium)," Journal of phase equilibria, vol. 21, no. 5, 2000.
[15] Y. Tung and M. L. Cohen, "Relativistic band structure and electronic properties of SnTe, GeTe, and PbTe," Physical Review, vol. 180, no. 3, p. 823, 1969.
[16] J. Li, Y. Chen, "High-performance GeTe thermoelectrics in both rhombohedral and cubic phases," Journal of the American Chemical Society, vol. 140, no. 47, pp. 16190-16197, 2018.
[17] J. Li, X. Zhang, Y. Chen, "Low-symmetry rhombohedral GeTe thermoelectrics," Joule, vol. 2, no. 5, pp. 976-987, 2018.
[18] R. I. Made, C. L. Gan, L. L. Yan, C. Lee, "Study of low-temperature thermocompression bonding in Ag-In solder for packaging applications," Journal of electronic materials, vol. 38, no. 2, pp. 365-371, 2009.
[19] H. Liu, G. Salomonsen, K. Wang, K. E. Aasmundtveit, and N. Hoivik, "Wafer-level Cu/Sn to Cu/Sn SLID-bonded interconnects with increased strength," IEEE Transactions on Components, Packaging and Manufacturing Technology, vol. 1, no. 9, pp. 1350-1358, 2011.
[20] L. Sun, M.-h. Chen, L. Zhang, P. He, and L.-s. Xie, "Recent progress in SLID bonding in novel 3D-IC technologies," Journal of Alloys and Compounds, vol. 818, p. 152825, 2020.
[21] T.-H. Chuang, W.-T. Yeh, C.-H. Chuang, and J.-D. Hwang, "Improvement of bonding strength of a (Pb, Sn) Te–Cu contact manufactured in a low temperature SLID-bonding process," Journal of alloys and compounds, vol. 613, pp. 46-54, 2014.
[22] H. Baker and H. Okamoto, "ASM handbook. vol. 3. alloy phase diagrams," ASM International, Materials Park, Ohio 44073-0002, USA, 1992. 501, 1992.
[23] P. Ramm, A. Klummp, B. Michael, H. Reichl, "Through silicon via technology—processes and reliability for wafer-level 3D system integration," in 2008 58th Electronic Components and Technology Conference, 2008, pp. 841-846: IEEE.
[24] J.-Y. Chang, R.-S. Cheng, K.-S. Kao, T.-C. Chang, and T.-H. Chuang, "Reliable microjoints formed by solid–liquid interdiffusion (SLID) bonding within a chip-stacking architecture," IEEE Transactions on Components, Packaging and Manufacturing Technology, vol. 2, no. 6, pp. 979-984, 2012.
[25] H. Xu, T. Sumi, H. Heikkinen, "Wafer-level SLID bonding for MEMS encapsulation," Advances in manufacturing, vol. 1, no. 3, pp. 226-235, 2013.
[26] C. Yang, H. Lai, J. Hwang, and T. Chuang, "Diffusion soldering of Pb-doped GeTe thermoelectric modules with Cu electrodes using a thin-film Sn interlayer," Journal of electronic materials, vol. 42, no. 3, pp. 359-365, 2013.
[27] K.-N. Chen, A. Fan, C. Tan, R. Reif, and C. Wen, "Microstructure evolution and abnormal grain growth during copper wafer bonding," Applied Physics Letters, vol. 81, no. 20, pp. 3774-3776, 2002.
[28] P. M. Agrawal, B. M. Rice, and D. L. Thompson, "Predicting trends in rate parameters for self-diffusion on FCC metal surfaces," Surface Science, vol. 515, no. 1, pp. 21-35, 2002.
[29] K.-N. Chen, A. Fan, C. Tan, and R. Reif, "Temperature and duration effects on microstructure evolution during copper wafer bonding," Journal of Electronic Materials, vol. 32, no. 12, pp. 1371-1374, 2003.
[30] T. Kim, M. Howlader, T. Itoh, and T. Suga, "Room temperature Cu–Cu direct bonding using surface activated bonding method," Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, vol. 21, no. 2, pp. 449-453, 2003.
[31] A. Shigetou, T. Itoh, M. Matsuo, N. Hayasaka, K. Okumura, and T. Suga, "Bumpless interconnect through ultrafine Cu electrodes by means of surface-activated bonding (SAB) method," IEEE transactions on advanced packaging, vol. 29, no. 2, pp. 218-226, 2006.
[32] C.-M. Liu, H.-W. Lin, Y.-S. Huang, C. Chen, K.-N. Tu, "Low-temperature direct copper-to-copper bonding enabled by creep on (111) surfaces of nanotwinned Cu," Scientific reports, vol. 5, no. 1, pp. 1-11, 2015.
[33] C. Chen, C.-M. Liu, H.-W. Lin, K.-N. Tu, "Low-temperature and low-pressure direct copper-to-copper bonding by highly (111)-oriented nanotwinned Cu," in 2016 Pan Pacific Microelectronics Symposium (Pan Pacific), 2016, pp. 1-5: IEEE.
[34] D. Lim, S. Goulet, M. Bergkvist, J. Wei, K. Leong, and C. Tan, "Enhancing Cu-Cu diffusion bonding at low temperature via application of self-assembled monolayer passivation," Journal of The Electrochemical Society, vol. 158, no. 10, p. H1057, 2011.
[35] Y.-P. Huang, Y.-S. Chiang, R.-N. Tzeng, C.-T. Chaung, W. Huang, "Novel Cu-to-Cu Bonding With Ti Passivation at 180°C in 3-D Integration," IEEE Electron Device Letters, vol. 34, no. 12, pp. 1551-1553, 2013.
[36] I. Karakaya and W. Thompson, "The Ag-O (silver-oxygen) system," Journal of phase equilibria, vol. 13, no. 2, pp. 137-142, 1992.
[37] J. Assal, B. Hallstedt, and L. J. Gauckler, "Thermodynamic assessment of the silver–oxygen system," Journal of the American Ceramic Society, vol. 80, no. 12, pp. 3054-3060, 1997.
[38] C. Oh, S. Nagao, T. Kunimune, and K. Suganuma, "Pressureless wafer bonding by turning hillocks into abnormal grain growths in Ag films," Applied Physics Letters, vol. 104, no. 16, p. 161603, 2014.
[39] C. Oh, S. Nagao, and K. Suganuma, "Pressureless bonding using sputtered Ag thin films," Journal of electronic materials, vol. 43, no. 12, pp. 4406-4412, 2014.
[40] H. Zhang, T. Sugahara, "Nearly perfect Ag joints prepared by Ag stress-migration-bonding (SMB) process," in 2018 Second International Symposium on 3D Power Electronics Integration and Manufacturing (3D-PEIM), 2018, pp. 1-4: IEEE.
[41] C. Gui, M. Elwenspoek, N. Tas, and J. G. Gardeniers, "The effect of surface roughness on direct wafer bonding," Journal of applied physics, vol. 85, no. 10, pp. 7448-7454, 1999.
[42] S. Chen, F. Ke, M. Zhou, and Y. Bai, "Atomistic investigation of the effects of temperature and surface roughness on diffusion bonding between Cu and Al," Acta Materialia, vol. 55, no. 9, pp. 3169-3175, 2007.
[43] J. Wu, Y. Huo, and C. C. Lee, "Direct Ag-Ag bonding by in-situ reduction of surface oxides for advanced chip-package interconnection," Materialia, vol. 4, pp. 417-422, 2018.
[44] L.-P. Chang, S.-Y. Huang, T.-C. Chang, and F.-Y. Ouyang, "Low temperature Ag-Ag direct bonding under air atmosphere," Journal of Alloys and Compounds, vol. 862, p. 158587, 2021.
[45] M. J. Aziz, "Thermodynamics of diffusion under pressure and stress: Relation to point defect mechanisms," Applied physics letters, vol. 70, no. 21, pp. 2810-2812, 1997.
[46] Y. Kim, S. Park, and S. E. Kim, "The Effect of an Ag Nanofilm on Low-Temperature Cu/Ag-Ag/Cu Chip Bonding in Air," Applied Sciences, vol. 11, no. 20, p. 9444, 2021.
[47] B. Lee, J. Park, S.-j. Jeon, K.-w. Kwon, and H.-j. Lee, "A study on the bonding process of Cu bump/Sn/Cu bump bonding structure for 3D packaging applications," Journal of The Electrochemical Society, vol. 157, no. 4, p. H420, 2010.
[48] H. Ono, T. Nakano, and T. Ohta, "Diffusion barrier effects of transition metals for Cu/M/Si multilayers (M= Cr, Ti, Nb, MO, Ta, W)," Applied physics letters, vol. 64, no. 12, pp. 1511-1513, 1994.
[49] X. Zhu, L. Cao, W. Zhu, and Y. Deng, "Enhanced interfacial adhesion and thermal stability in bismuth telluride/nickel/copper multilayer films with low electrical contact resistance," Advanced Materials Interfaces, vol. 5, no. 23, p. 1801279, 2018.
[50] K. Keong and W. Sha, "Crystallisation and phase transformation behaviour of electroless nickel-phosphorus deposits and their engineering properties," Surface Engineering, vol. 18, no. 5, pp. 329-343, 2002.
[51] B. Lee, H. Jeon, S. Kim, K.-w. Kwon, J.-W. Kim, and H.-j. Lee, "Introduction of an electroless-plated Ni diffusion barrier in Cu/Sn/Cu bonding structures for 3D integration," Journal of The Electrochemical Society, vol. 159, no. 2, p. H85, 2011.
[52] L. Liu, Z. Chen, Z. Zhou, G. Chen, F. Wu, and C. Liu, "Diffusion barrier property of electroless Ni-WP coating in high temperature Zn-5Al/Cu solder interconnects," Journal of Alloys and Compounds, vol. 722, pp. 746-752, 2017.
[53] T. Lin, C. Liao, and A. T. Wu, "Evaluation of diffusion barrier between lead-free solder systems and thermoelectric materials," Journal of electronic materials, vol. 41, no. 1, pp. 153-158, 2012.
[54] C.-Y. Ko and A. T. Wu, "Evaluation of diffusion barrier between pure Sn and Te," Journal of electronic materials, vol. 41, no. 12, pp. 3320-3324, 2012.
[55] Y. N. Nguyen, S. Kim, S. H. Bae, and I. Son, "Enhancement of bonding strength in BiTe-based thermoelectric modules by electroless nickel, electroless palladium, and immersion gold surface modification," Applied Surface Science, vol. 545, p. 149005, 2021.
[56] H. NAWAFUNE, K. SHIROGUCHI, S. MIZUMOTO, Y. KOHASHI, and K. OBATA, "Direct electroless silver plating on copper metal from succinimide complex bath using imidazole as the reducing agent," Journal of The Surface Finishing Society of Japan, vol. 52, no. 10, pp. 702-707, 2001.
[57] Y.-C. Lin, J.-D. Huang, S.-C. Chen, T.-H. Chuang, "Solid liquid interdiffusion bonding of Zn4Sb3 thermoelectric material with Cu electrode," Journal of Electronic Materials, vol. 45, no. 10, pp. 4935-4942, 2016.
[58] S. Kim, S. H. Bae, and I. Son, "Effect of the ENEPIG Process on the Bonding Strength of BiTe-based Thermoelectric Elements," Archives of Metallurgy and Materials, vol. 66, 2021.