臺灣博碩士論文加值系統

晶圓級封裝形式WLCSP(Wafer Level Chip Scale Package)，由於其尺寸較小可提高產品之聚集度，已逐漸成為未來發展的趨勢。其中連結錫球與晶片二者間之多層金屬薄膜(Under Bump Metallurgy簡稱UBM)，對產品的好壞具有決定性之影響力。另外傳統上所使用之含鉛錫球中鉛的含量，會對環境及人體健康造成危害，各先進國家莫不積極尋找無鉛之替代材料。
本研究乃將著手以無鉛錫球含UBM材料之WLCSP封裝模式，建構在含雙層微盲孔(Micro-via)之增層(Build-up)電路板上，利用有限元素分析法ANSYS6.0之軟體，在熱循環負荷下進行計算模擬，以瞭解整體封裝結構之變形、微盲孔及錫球應力應變及遲滯曲線之變化和壽命預估等機械行為。其間分別採用多線性等向硬化( Multilinear isotropic hardening ) 、黏塑性(Viscoplasticity)及葛拉佛拉-阿瑞尼阿斯潛變模式(Garofalo-Arrhenius creep model) 等三種不同材料性質理論，以分析錫球並比較其差異。
透過本計畫之完成，希望能提供業界對無鉛錫球及UBM材料之應用更深一層的認識，有利於自然環境的保護，並縮短開發時間，提升產品的競爭力。

The wafer level chip scale package (WLCSP) has increasingly become popular due to its wafer-sized compact package. In the WLCSP, the under bump metallurgy (UBM) which connects the solder joint and the chip, is crucial for the package reliability. Additionally, the lead contained in conventional solder joints is adverse to environments and human health, so that many countries are seeking lead-free solder-material for replacement.
This study focuses on the WLCSP with lead-free UBM solder joint mounted on the build-up electric board with double-layered micro-via. Finite element analysis ANSYS 6.0 is used for simulations under thermal cycling to investigate the deformations of entire package, micro-via and the changes of stress-vs.-strain hysterisis curve for solder joints. The fatigue life prediction is also included. Three material property theories are adopted, such as viscoplasticity, multilinear isotropic hardening and Garofalo-Arrhenius creep model, to analyze solder joins and compare the differences between results.
The complication of this study could give some suggestion to manufacturers the application of lead-free solder joint and UBM, urge them to pay attentions to environmental protections, and furthermore shorten the development period to enhance the competitiveness.

中文摘要I
英文摘要II
誌謝III
目錄 IV
表目錄 VII
圖目錄 VIII
符號說明XV
第一章 緒論1
1-1 前言1
1-2 研究動機與目的2
1-3 文獻回顧2
1-4 研究方法4
1-5 章節提要4
第二章 理論基礎6
2-1 研究主題6
2-2 無鉛錫球的應用7
2-3 UBM的應用9
2-4 黏塑性理論分析基礎13
2-4-1 牛頓-瑞佛森非線性求解理論13
2-4-2 等向性硬化法則17
2-4-3 亞蘭德模型18
2-4-4 葛拉佛拉-阿瑞尼阿斯潛變模式26
2-5 有限元素分析28
2-5-1 有限元素基本架構28
2-5-2 時間步長的選擇35
2-6 低循環疲勞壽命37
第三章 模型建立與評估45
3-1 分析模型建立45
3-1-1 WLCSP封裝結構模型46
3-1-2 基本假設條件48
3-1-3 邊界條件與負載48
3-2 ANSYS有限元素分析軟體49
3-3 理論分析比較55
3-3-1 多線性等向硬化分析55
3-3-2 黏塑性分析56
3-3-3 潛變分析58
3-3-4 結果比較59
3-4 多層金屬薄膜(UBM)分析60
第四章 無鉛錫球含UBM之結構分析95
4-1 三維模型分析95
4-1-1 整體封裝結構之變位95
4-1-2 錫球結構分析96
4-1-3 微盲孔結構分析97
4-1-4 鎳金屬層結構分析97
4-1-5 銅金屬層結構分析98
4-1-6 鈦金屬層結構分析100
4-1-7 鋁金屬層結構分析101
4-1-8 氮化矽保護層結構分析102
4-1-9等效潛變應變範圍分析102
4-2 疲勞壽命之預測及可靠度分析103
4-3結果比較104
第五章 結論134
5-1 結論134
5-2 未來研究方向135
參考文獻137

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