臺灣博碩士論文加值系統

本實驗以敏化活化法成長無電鍍銅晶種層，並整合電鍍銅技術製備銅導線薄膜。將試片先以10 % HF進行蝕刻處理，粗糙度最低，且能夠均勻去除TaN表面的原生氧化層，促進後續的敏化活化。在溫度75 ℃下進行敏化活化，能夠在試片表面形成緻密且均勻散佈，尺寸大小約10 nm的Sn-Pd聚團。無電鍍銅則是以這些Pd為成核點，成長一層緻密且連續的晶種層；晶種層在200 mTorr Ar氣氛下400 ℃退火30 min，可減少內部缺陷提高晶種層的結晶性，使30 nm厚的晶種層電阻率降至3.12 μΩ-cm，且退火處理後附著力變佳，表面粗糙度降至1.92 nm；另外可以成功在0.18 μm 的特徵孔洞內覆蓋一層30 nm的無電鍍銅晶種層。
在退火過的無電鍍銅晶種層上電鍍銅膜，最佳的電流密度為3.33 mA/cm2，若電鍍時不進行攪拌，在較高電流密度時由於反應速率太快，局部濃度較高的地方，會有銅自由析出沈積於銅膜表面，造成銅膜表面變粗糙且堆積密度降低，電阻率因而升高；攪拌鍍液可使銅離子擴散速率加快，鍍液濃度分布均勻，因而加快反應的速率，也減少自由析出現象。此外，電鍍銅膜在Ar氣氛下400 ℃退火30 min，銅膜可通過附著力測試；180 nm銅膜電阻率下降至2.14 μΩ-cm ，1.9 μm銅膜更降至1.77 μΩ-cm，相當接近銅塊材的1.67 μΩ-cm；電鍍銅時若加入添加劑，可以成功填滿0.18 μm 的特徵孔洞，形成超填充。
以上結果可知，無電鍍銅晶種層與電鍍銅整合，在下世代銅導線製程將極具潛力。

摘要……………………………………………………………………...I
誌謝...........................................................................................................II
目錄..........................................................................................................III
圖目錄………………………………………………………………….VII
表目錄………………………………………………………………...XIII
壹、前言...................................................................................................1
貳、文獻回顧…………………………………………………………...3
2.1. 積體電路之金屬內連線…………………………………………...3
2.1.1. RC延遲效應(RC delay)…………………………………….3
2.1.2. 電遷移效應(Electromigration)……………………………..3
2.1.3. 內連線材料之選擇………………………………………....6
2.1.4. 銅化學機械研磨技術(Cu CMP) [17]……………………....8
2.1.5. 銅金屬內連線製作之Damascence製程…………………..8
2.2. 擴散阻隔層 [21]………………………………………………….10
2.3. 銅金屬內連線之沉積技術 [17]………………………………….16
2.3.1. 物理氣相沈積 [28]………………………………………..17
2.3.2. 化學氣相沈積 [17,29]…………………………………….19
2.3.3. 電化學沈積………………………………………………...20
2.3.3.1. 電鍍銅……………………………………………21
2.3.3.1-1 陽極的選用……………………………21
2.3.3.1-2 電鍍銅鍍液成份………………………21
2.3.3.1-3 銅晶種層(Seed Layer)………………...25
2.3.3.2. 無電鍍銅…………………………………………26
2.3.3.2-1 無電鍍銅製程之發展…………………26
2.3.3.2-2 無電鍍銅製程之前處理………………28
2.3.3.2-3 無電鍍銅鍍液之組成與特性…………30
2.3.3.2-4 無電鍍銅之化學反應式與反應機制…35
2.3.3.2-5 無電鍍銅的發展與應用………………36
2.3.3.2-6 應用無電鍍銅製作半導體銅製程的晶種層……………………………...37
2.4. 研究目的…………………………………………………………..38
參、實驗步驟..........................................................................................39
3.1. 基材………………………………………………………………..39
3.2. 敏化活化無電鍍銅晶種層………………………………………..39
3.2.2. 蝕刻處理…………………………………………………...39
3.2.3. 敏化活化處理……………………………………………...39
3.2.4. 無電鍍銅晶種層…………………………………………...41
3.3. 在無電鍍銅晶種層上進行電鍍銅………………………………..41
3.3.1. 試片清洗…………………………………………………...41
3.3.2. 電鍍銅……………………………………………………...41
3.4. 實驗流程圖………………………………………………………..45
3.4.1. 敏化活化無電鍍銅晶種層實驗流程圖…………………...45
3.4.2. 在無電鍍銅晶種層上進行電鍍銅實驗流程圖…………...46
3.5. 儀器設備簡介……………………………………………………..47
3.5.1. 無電鍍銅設備……………………………………………...47
3.5.2. 電鍍銅設備………………………………………………...47
3.6. 熱處理……………………………………………………………..47
3.7. 微結構觀察………………………………………………………..50
3.7.1. 掃描式電子顯微鏡(SEM)分析……………………………50
3.7.2. 原子力顯微鏡(AFM)分析…………………………………50
3.7.3. 穿透式電子顯微鏡(TEM)分析……………………………50
3.8. 成份分析…………………………………………………………..50
3.8.1. 歐傑電子能譜儀(AES)分析……………………………….50
3.8.2. 拉塞福背向散射分析儀(RBS)分析……………………….51
3.9. 性質分析…………………………………………………………..51
3.9.1. X-ray繞射儀分析…………………………………………..51
3.9.2. 電阻率量測………………………………………………...51
3.9.3. 附著力測試…………………………………………….......52
3.9.4. 應力量測…………………………………………………...52
肆、結果與討論………………………………………………………..56
4.1. 擴散阻隔層成份分析……………………………………………..56
4.1.1. 拉塞福背向散射分析儀分析結果………………………...56
4.1.2. X-ray繞射圖分析結果……………………………………..56
4.1.3. AFM分析結果……………………………………………...56
4.2. 無電鍍銅晶種層製程研究………………………………………..60
4.2.1. 蝕刻處理…………………………………………………...60
4.2.1.1. 不同蝕刻成份之AFM分析……………………..60
4.2.2. 敏化活化處理……………………………………………...66
4.2.2.1. 不同敏化活化溫度之銅膜電阻率分析…………66
4.2.2.2. 不同敏化活化溫度之銅膜SEM分析…………..69
4.2.2.3. 敏化活化後之表面AFM分析…………………..69
4.2.2.4. 敏化活化後之TEM分析………………………..78
4.2.2.5. Sn-Pd聚團之RBS分析………………………….78
4.2.3. 無電鍍銅晶種層分析……………………………………...78
4.2.3.1. 晶種層SEM分析………………………………...78
4.2.3.2. 晶種層AFM分析………………………………..83
4.2.3.3. 晶種層TEM分析…………………………….......83
4.2.3.4. 晶種層電阻率分析………………………………83
4.2.3.5. 晶種層X-ray分析……………………………….92
4.2.3.6. 晶種層附著力分析………………………………92
4.2.3.7. 晶種層的階梯覆蓋能力研究……………………95
4.3. 無電鍍銅晶種層與電鍍銅製程整合研究………………………..95
4.3.1. 不攪拌條件下不同電流密度對電鍍銅影響之研究……...95
4.3.1.1. 電鍍銅SEM分析………………………………..95
4.3.1.2. 電鍍銅電阻率分析………………………………98
4.3.1.3. 電鍍銅AFM分析……………………………....106
4.3.2. 攪拌對電鍍銅影響之研究……………………………….106
4.3.2.1. 電鍍銅SEM分析………………………………111
4.3.2.2. 電鍍銅不同退火溫度電阻率分析……………..111
4.3.2.3 電鍍銅X-ray分析………………………………117
4.3.2.4 電鍍銅熱循環應力分析………………………...117
4.3.2.5. 電鍍銅附著力分析……………………………..120
4.3.2.6. 電鍍銅填洞能力研究…………………………..120
伍、結論………………………………………………………………122
陸、參考文獻…………………………………………………………124

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