臺灣博碩士論文加值系統

隨著科技日益進步，微電子產品更脫離不開微型化的發展，因此銲接點也會跟著縮小。目前半導體產業中接點可靠性疑慮已經成為不可避免的問題，像是銲接點金屬相互反應生成脆性介金屬化合物(Intermetallic compound, IMC)，使得機械強度下降，此外，使用時流經銲點電流密度迅速增加，接點不僅僅會受到電遷移效應之影響，其中銲接點會因電流而生成熱能，這表示接點也會受到熱效應之衝擊，在長時間下因溫度可能使銲接點之性質產生變化，也是對電子產品使用壽命的疑慮之一。
電鍍技術通常使用於製造銅金屬化線路以作為與銲料的接點，而根據先前許多研究表示，銅電鍍過程裡溶液中的添加劑會產生一些有機雜質，進而在電鍍過程中可能被摻入沉積銅層中，金屬和銲料反應下，經過熱老化過程，在高溫時銲料與銅反應之界面處會誘發嚴重的孔洞生成，這會導致接點受到破壞的機率提升，因此本研究將會探討電鍍添加劑對電鍍銅的性質之影響，並且針對微電子產品在實際應用下所受到之不同溫度影響做模擬實驗，以觀察溫度對銲料與電鍍銅之界面反應，再更一步討論其對接點可靠度的影響。
本研究發現全部銅電鍍配方經Cu/Sn熱處理反應，溫度越高IMC成長越快，低溫則反應生成厚度及形狀不均，而CS(Cl-+SPS)，PCS(PEG+Cl-+SPS)，Cu foil三者界面均無孔洞，但是PC(PEG+Cl-)配方在低溫其IMC容易脆裂，而在高溫或長時間下不僅僅IMC成長厚度增加，還會有多層結構產生。動力學分析發現高溫下越接近體積擴散，四點探針偵測CS有最低電阻率。在推球實驗中， PC經過低溫熱處理後的機械強度最弱，此結果可經過聚焦型離子束(FIB)發現在低溫熱處理的Cu3Sn/Cu之間累積相當多孔洞而驗證，此外高溫則是發現孔洞分布位置在IMC內部及界面處，且孔洞周圍佈滿灰黑色物質。從二次離子質譜儀(SIMS)之雜質濃度分析結果得到各溫度下雜質濃度相對較高。熱處理越高溫，Cu6Sn5晶粒越大，而只有PC配方的Cu6Sn5上分布許多voids，分析發現是由三氯苯氣體所誘發。

Nowadays, development of microelectronic products follows the trend of miniaturization with the progress of technology. Therefore, the size of the solder joints shrinks and the reliability issue can not be avoided in semiconductor industry. One main reliability issue is the joint structure due to the formation of brittle intermetallic compounds (IMCs) resulting from the solder/metallization reactions. Also, the current density through the solder joints increases rapidly. The joints are not only affected by electromigration but also attacked by the thermal effect caused by current.
The electroplating technique is commonly used in fabricating the Cu metallization in the solder joints. Previous studies indicated that some impurities originated from the additives of electroplating solution. The impurities were incorporated in the Cu deposit and caused severe void formation at the solder/Cu interface during thermal aging. In this study, we investigate the effect of additives on the properties of electroplated copper. Moreover, the solder/electroplated copper interfacial reaction was observed and the reliability of solder joints was discussed.
The IMCs of the Cu/Sn reaction for all copper electroplating formulas grow at a faster rate at higher temperatures during thermal aging. The Sn/Cu interfaces prepared with CS (Cl-+SPS), PCS (PEG+Cl-+SPS), Cu foil are void-free. We find the IMCs formed at the Sn/Cu interface prepared with PC (PEG+Cl-) will easily break at low temperature and exhibit a multi-layer structure at high temperature. Kinetic analysis indicates the bulk-diffusion at high temperature. The four-point probe measurement shows that the Cu deposit prepared by the CS formula has the lowest resistivity.
Focused Ion Beam system (FIB) images show the voids accumulated at the Cu/Cu3Sn interface at low-temperature heat treatment which means that the mechanical strength of the joint prepared by the PC formula is the weakest at low temperature aging. Conversely, the voids distribute in IMC and interface at high temperature and the gray-dark substance appears around the periphery of the voids. Time-of-Flight Secondary Ion Mass Spectrometer (TOF-SIMS) results show the impurity concentration is similar.

摘要 i
Abstract ii
目錄 iv
圖目錄 vi
表目錄 x
第1章、緒論 1
第2章、文獻回顧 2
2.1為何使用電鍍銅 2
2.2電鍍添加劑在電鍍上之應用 4
2.3電鍍添加劑和雜質殘留之影響 9
2.4電鍍添加劑對銅/銲料反應之影響 17
2.5擴散機制 29
2.6溫度對電鍍銅/銲料反應之影響 32
2.7溫度對電鍍銅/銲料接點可靠度之影響 36
第3章、實驗方法 41
3.1 電鍍銅製備 41
3.2 電鍍銅/錫樣品製備 42
3.3 電鍍銅/錫之固/固反應 42
3.4 固/固反應界面分析 43
3.5 電鍍銅/錫接點機械強度測試 43
3.6 電鍍銅電性分析 44
3.7 電鍍銅雜質分析 44
3.8 氣相層析質譜儀分析 44
第4章、結果與討論 46
4.1 不同溫度下純銅/錫之固/固反應 46
4.2 不同溫度下不同添加劑之電鍍銅/錫之固/固反應 47
4.3不同溫度下之不同電鍍銅/錫介金屬化合物成長趨勢 53
4.4不同添加劑之電鍍銅電性分析 55
4.5不同溫度下之不同電鍍銅/錫接點機械強度測試 56
4.6不同溫度下電鍍銅/錫之固/固反應孔洞之分布情況 59
4.7不同溫度下之不同電鍍銅雜質分佈 63
4.8不同溫度下之不同電鍍銅/錫反應之Cu6Sn5表面型態 64
4.9電鍍PC配方之Cu6Sn5上孔洞形成原因分析 66
第5章、結論 71
第6章、參考文獻 73

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