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℃.

Abstract
Content
Chapter 1 Introduction 1
Chapter 2 Literature Review 4
2.1 Joining process with Ag nanoparticles paste 4
2.2 Reliability 11
2.2.1 Shear strength test 11
2.2.2 Thermal cycle test 16
Chapter 3 Experimental Details 18
3.1 Specimen preparation 18
3.1.1 Silver nanoparticles paste 18
3.1.2 Specimen fabrication 19
3.2 Characterization methods 21
3.2.1 Scanning electron microscopy 21
3.2.2 Atomic force microscope 21
3.2.3 Four-point probe 21
3.2.4 Vickers hardness test 22
3.2.5 Shear strength test 23
3.3 Thermal cycle test 24
Chapter 4 Experimental Results 25
4.1 Microstructure observation and property analysis of the as-sintered samples 25
4.1.1 Morphology evolution 25
4.1.2 Electrical properties 30
4.1.3 Hardness 32
4.2 Microstructure observation and property analysis of the as-bonded samples 34
4.2.1 Cross-sectional observation 34
4.2.2 Shear strength 46
4.2.3 Thermal cycle test 51
Chapter 5 Discussions 60
5.1 Effect of different sintering temperatures 60
5.1.1 Microstructure changes of the as-sintered samples 60
5.1.2 Resistivity and hardness of the as-sintered samples 63
5.2 Effect of different bonding temperatures on the microstructure and properties 67
Chapter 6 Conclusion 71
Reference 72

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