焊錫接點(solder joints)是電子封裝常見的電訊接點，也用於封裝體和PCB （印刷電路板）之間的機械支撐。在熱循環測試(thermal cycling test, TCT)時，由於電子組件和PCB之間熱膨脹係數不匹配(Coefficient of Thermal Expansion Mismatch)所產生的熱應變，使得材料間發生疲勞破壞，尤其銲錫接點與焊墊(pad)的交界處常為裂紋發生位置，因此焊錫接點的可靠度為首要課題。並且無鉛焊錫有較高的對應溫度(homologeous temperature)，在本研究熱循環負載下，操作溫度大於焊錫接點熔點溫度的1/3倍，因此潛變是主要的破壞機制。
加速熱循環測試被廣泛運用於封裝的可靠度評估，為了降低可靠度測試的時間，加快升降溫速率(ramp rate)或降低持溫時間(dwell time)的方法常被用來縮短測試的時間，然而當溫度循環的升降溫速率越快，會造成材料應變速率和應力的性質發生變化，影響材料破壞情形，尤其JEDEC (Joint Electron Device Engineering Council) standard對於TCT的升降溫速率條件沒有嚴格定義，測試溫度歷程不一致的情形，將影響焊錫接點的可靠度評估。
本文以模擬的方式建立功率模組(Power Module)的大面積焊錫和晶圓級晶片尺寸封裝(Wafer Level Chip Scale Packaging, WLCSP)的錫球之有限元素模型，探討升溫速率改變時，不同應變速率下焊錫接點的物理損傷量，藉此了解應變速率與焊錫接點的幾何和疲勞壽命之間的關聯性。
本研究中使用線性溫度相關的楊氏係數和雙曲正弦潛變方程式來描述焊錫接點的變形。此外，本研究選定合適的網格密度分析應變率對於焊錫接點損傷的影響，使用Darveaux相關的經驗公式求得焊錫接點的壽命週期數，並將模擬結果與實驗文獻進行比對，驗證焊錫接點的疲勞壽命，本文提供了一個精確的元素尺寸，將可用於焊錫接點潛變分析。
藉由以上的分析，功率模組的大面積焊錫和WLCSP的錫球兩種不同幾何形狀的焊錫接點之模擬結果有一致的情形，當焊錫接點承受之應變率越高，皆導致封裝體的可靠度有下降的趨勢。

摘要 II
Abstract IV
誌謝 VI
表目錄 X
圖目錄 XII
第一章 緒論 1
1.1研究動機 1
1.2文獻回顧 3
1.3研究目標 9
第二章 基礎理論 12
2.1有限元素法理論基礎 12
2.1.1線彈性有限元素法理論 12
2.1.2材料非線性有限元素法理論 17
2.1.3數值方法與收斂準則 20
2.2潛變行為 22
2.3焊錫接點可靠度分析 24
2.3.1 Coffin-Manson應變法 25
2.3.2 Darveaux能量密度法 26
第三章 研究方法 27
3.1有限元素模型之基本假設 27
3.2功率模組之幾何尺寸與有限元素模型的建立 28
3.3功率模組之材料設定 30
3.4 功率模組之邊界條件與負載設定 31
3.5 模擬結果與分析 34
3.5.1二維模型模擬與實驗文獻之驗證 34
3.5.2焊錫接點之潛變行為探討 39
3.5.3 溫度負載形式影響 41
3.5.4 焊錫接點之幾何影響 43
3.5.5溫度負載範圍之影響 45
3.6 黏彈性銲錫材料參數 47
第四章 功率模組與WLCSP潛變行為分析 49
4.1功率模組模擬分析 49
4.1.1焊錫接點之潛變行為分析 49
4.1.1.1疲勞壽命預估驗證 51
4.1.1.2應變率對焊錫接點之疲勞破壞影響 54
4.2 WLCSP模擬分析 56
4.2.1有限元素模型之基本假設 57
4.2.2 WLCSP之幾何尺寸與有限元素模型的建立 58
4.2.3 WLCSP之材料設定 60
4.2.4 WLCSP之邊界條件與負載設定 61
4.2.5錫球之潛變行為探討 62
4.2.5.1疲勞壽命預估驗證 63
4.2.5.2應變率對錫球之疲勞破壞影響 66
第五章 結論與未來展望 68
參考文獻 72

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