3D-IC是一種利用三維垂直晶片堆疊的方式來提升效能以跟上對於電子產品運算能力的強烈需求。目前兩種用於垂直晶片堆疊的關鍵技術：微銲點以及銅-銅直接接合吸引到了廣大的注意。以微銲點的發展而言，銲點之間的間距越小，I/O數就越大，而I/O數和效能有直接的關聯。研究指出銲點的尺度極限約為銲點間間距的一半，因此低尺度的銲點受到了廣泛的研究。此外，隨著穿戴式可撓裝置以及高頻率通訊晶片的快速發展，現今普遍使用的傳統銲料會因過高的接合溫度而傷害到產品。為了避免這樣的情況發生，低溫接合銲料，例如銦以及錫鉍銲料在應用上有很大的潛力。
藉由在銅基板中摻雜鎳及鋅可改善傳統銅錫銅系統，並帶來許多好處，如介金屬化合物的強化、晶粒結構的改造以及阻礙孔洞的生成。本實驗闡述了使用Cu18Ni18Zn/Sn3.5Ag/Cu18Ni18Zn系統的好處，以及長時間熱處理前後的性質比較。以結果而言，Cu18Ni18Zn/Sn3.5Ag/Cu18Ni18Zn系統展現優異的機械強度以及熱穩定性，使它成為先進封裝中的理想選擇。
低溫銲料的部分則以微米尺度下的Cu/In/Cu以及Cu/In/Ni系統在內文中討論。實驗中發現兩種情況底下，在接合界面處形成的孔洞將會變得更加嚴重。第一種情況是在銲點的尺度極小的情況下，第二種情況則發生在一側的銅基板更換成鎳基板時。此外，利用ANSYS有限元素分析法模擬擴散行為，其結果也呈現相似的趨勢。綜上所述，這些劣化現象也表明銦基銲料在尺度微縮下具有其限制及極限。

3D-IC is a novel method that utilizes horizontal stacking of chips to keep up with the strong demand on computing power of electronic devices. Two key technologies in chip stacking have drawn lots of attention, which are microbump and direct Cu-Cu bonding. In terms of advancement in microbump, lower pitch size between solder joint implies higher numbers of I/O, which is directly connected to its performance. The limitation of bump height is reported to be about the half of the pitch size, thus low-scale solder joint has been widely researched. Moreover, as the rapid development of flexible wearable devices and high-frequency communication chip, the high bonding temperature of traditional Pb-free solder might cause damage. To prevent this situation from occurring, low-temperature bonding materials, such as indium and Sn-Bi solder, exhibit great potential in application.
Nickel and zinc doping into copper substrates in traditional Cu/Sn/Cu system would bring some advantages, such as strengthening of intermetallic compounds (IMCs), modification of grain structure and retardation of void formation. This study explicit the benefits of Cu18Ni18Zn/Sn3.5Ag/Cu18Ni18Zn system, as well as the properties change before and after long-term aging treatment. In short, Cu18Ni18Zn/Sn3.5Ag/Cu18Ni18Zn system demonstrates favorable high mechanical properties and thermal stability, which makes it a feasible choice in future advanced packaging.
As for the low-temperature solder joint, Cu/In/Cu and Cu/In/Ni systems are addressed in micron-meter scale. Voids formed at bonding interface are discovered to be more severe under two conditions. First, solder joint is under extremely low bump height. Second, one side of the copper substrates is replaced by nickel substrate. Moreover, commercial software ANSYS is used to simulate the diffusion behavior, and the outcome also display the similar trend. It appears that the deterioration implies the limitation and confinement in miniaturization of indium-based solder joint.

摘要 i
Abstract ii
Contents v
List of Tables vii
Figure Captions viii
Chapter 1. Introduction 1
1.1 Background 1
1.2 Motivations and Goals 2
Chapter 2. Literature Review 5
2.1 Electronic Package 5
2.2 Solder Bump 7
2.2.1 Pb-free Solder 8
2.2.2 Low-temperature solder 9
2.3 Under Bump Metallurgy (UBM) 10
2.3.1 Cu-based UBM 11
2.3.2 Novel Cu-Ni-Zn UBM 11
2.4 Metallurgical Reactions in Pb-free Solder joints 12
2.4.1 Metallurgical Reaction in traditional Sn-Ag/Cu Solder Joints 12
2.4.2 Interfacial Reaction in Cu/Sn-Ag/Cu Microbump 13
2.4.3 Thermocompression bonding (TCB) 14
2.5 Properties of Cu6Sn5-based IMC 15
2.5.1 Crystal structure of Cu6Sn5 15
2.5.2 Grain structure of Cu6Sn5 15
2.6 Ni Effect on Cu-Sn Metallurgical Reaction 16
2.6.1 Effect of Ni on Cu6Sn5 16
2.6.2 Effect of Ni on Cu3Sn 17
2.7 Zn Effect on Cu-Sn Metallurgical Reaction 18
2.7.1 Effect of Zn on Cu6Sn5 and Cu3Sn 18
Chapter 3. Experiment Design 31
3.1 Sample preparation for Cu/Sn3.5Ag/Cu and Cu18Ni18Zn/Sn3.5Ag/Cu18Ni18Zn microbumps 31
3.2 Sample preparation for Cu/In/Cu and Cu/In/Ni microbumps with diffusion analyzation 32
Chapter 4. Result and Discussion 37
4.1 Microstructural observation and quantitative analysis of Cu/Sn/Cu microbump with Ni and Zn doping into Cu substrates 37
4.1.1 Morphology and Composition of As-reflow Samples with Different Conditions 37
4.1.2 Mechanical Properties of As-reflow Samples with Different Conditions 41
4.1.3 Morphology and Composition of Aged Samples with Different Conditions 44
4.2 Thermocompression bonding process induced heterogeneous phase transformation in Cu/In/Ni microbump 65
4.2.1 Microstructure and quantitative analysis of Cu/In/Cu and Cu/In/Ni microbump 66
4.2.2 Diffusion model of Cu/In/Cu and Cu/In/Ni microbump and study of real cases 67
Chapter 5. Conclusion 76
References 79

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