臺灣博碩士論文加值系統

銲錫在電子產品中主要被用作為連接電訊之接點。因為銲錫接點之失效直接關係到電子產品之使用壽命，所以其可靠度一直是重要的研究課題。過去銲錫接點之材料以錫鉛合金為主，但錫鉛合金含有對環境有害的鉛，近年來國際間紛紛立法限制有鉛銲錫之使用。因此，電子相關產業改採無鉛銲錫取代含鉛銲錫已成為必然之趨勢。就無鉛銲錫接點可靠度而言，無鉛合金受應力作用下之潛變變形造成之材料失效是一亟待解決之問題。本文的重心將專注於模擬錫銀銅3807(Sn3.8Ag0.7Cu)合金之潛變行為。

本論文主要目的是建構一組能更真實表現錫銀銅3807 黏塑性行為之材料本構模型。文中藉由狀態變數方法建構一新型黏塑性本構模型，並選擇背應力為主要的狀態變數，使本構模型可用來表現錫銀銅3807 之移動硬化行為。後再利用錫銀銅3807 在各溫度下之定應變率壓縮實驗數據作曲線擬合求取模型參數。然後採用此新型黏塑性本構模型模擬數種變負載形式外力作用，並與時間硬化潛變模型模擬結果、Anand 模型模擬結果、及銲錫潛變實驗結果進行比對。由比對結果發現：因能表現出錫銀銅3807 之移動硬化行為，本文所建構出之新型黏塑性本模型較其他兩種本構模型更能真實的描述材料之非線性潛變行為。

Solders are used extensively as electrical interconnects in microelectronic systems.In particularly, eutectic or near eutectic tin lead solders have been used widely in the last few decades. Due to the increasingly concerns for toxicity and environmental impact of lead, there is a major push in the electronics industry to shift to lead-free solders. There are, however, many questions regarding the reliability for lead-free solders remain unanswered. One of the key issues for lead-free reliability is the creep response of solder and the corresponding failure mechanism when the interconnect is subjected to either thermal or mechanical loads from manufacturing process or during service life.

This study is focused on modeling the creep behavior of SAC3807 (Sn3.8Ag0.7Cu) solder.In this research a unified viscoplastic constitutive model is developed for describing the inelastic behavior of SAC3807 solder. The viscoplastic constitutive model is based on a state-variable approach. Back stress, which is used for characterizing the kinematic hardening behavior, is selected as the state variable for the constitutive model. The model constants are determined from curve-fitting constant strain rate experimental results. Finally, a numerical model based on the unified viscoplastic constitutive model is applied to simulate several load histories and compared to numerical results obtained form simulations using time-hardening creep constitutive model, numerical results from Anand viscoplastic model and experimental solder creep characterization results. It is observed that, among the three creep constitutive models examined, the new model is the only one that could properly describe the transient creep response when the applied load jumps or reversals.

摘要..................................................... I

英文摘要................................................ II

誌謝.................................................... IV

目錄..................................................... V

表目錄.................................................. IX

圖目錄................................................... X

符號說明.............................................. XIII

第一章緒論............................................... 1

1.1 前言................................................. 1

1.2 文獻回顧............................................. 2

1.2.1 無鉛銲錫之機械性質................................. 2

1.2.2 潛變本構模型....................................... 5

1.2.3 黏塑性本構模型..................................... 9

1.3 研究方法............................................ 14

1.4 本文架構............................................ 15

第二章基礎理論.......................................... 17

2.1 潛變現象............................................ 17

2.2 潛變本構模型........................................ 20

2.2.1 潛變模型組成函數.................................. 20

2.2.2 時間硬化和應變硬化................................ 22

2.2.3 疊加型黏塑性本構模型.............................. 26

2.2.4 潛變流動方程式.................................... 26

2.3 黏塑性本構模型...................................... 30

2.3.1 狀態變數之選擇.................................... 32

2.3.2 狀態變數進化方程式................................ 34

2.3.3 黏塑性流動方程式.................................. 35

第三章無鉛銲錫壓縮實驗.................................. 39

3.1 壓縮實驗器材和準備.................................. 39

3.2 錫銀銅 3807 潛變壓縮實驗............................ 41

3.3 定應變率壓縮實驗.................................... 46

第四章時間硬化潛變模型.................................. 50

4.1 潛變本構模型........................................ 50

4.2 時間硬化潛變模型參數求取............................ 52

4.2.1 決定穩態潛變應變率................................ 53

4.2.2 決定穩態潛變模型之材料參數：C5、C6、C7............ 54

4.2.3 決定暫態潛變模型之材料參數：C1、C2、C3、C4 ....... 55

第五章 Anand 黏塑性本構模型............................. 59

5.1 Anand 黏塑性本構模型................................ 59

5.2 Anand 模型參數求取.................................. 64

5.2.1 模型參數求取步驟.................................. 64

5.2.1.1 決定飽和應力.................................... 64

5.2.1.2 決定穩態參數.................................... 66

5.2.1.3 決定暫態參數.................................... 67

5.2.1.4 決定其餘參數.................................... 69

5.2.2 模型參數討論...................................... 73

第六章修正 Armstrong-Frederick 本構模型................. 75

6.1 修正 Armstrong-Frederick 本構模型................... 75

6.1.1 黏塑性流動方程式.................................. 76

6.1.2 狀態變數進化方程式................................ 77

6.2 修正 Armstrong-Frederick 本構模型參數求取........... 81

6.2.1 求取飽和應力...................................... 81

6.2.2 求取模型穩態參數.................................. 81

6.2.3 求取模型暫態參數.................................. 83

第七章結果與結論........................................ 87

7.1 模擬與實驗比對...................................... 88

7.1.1 單向潛變行為...................................... 88

7.1.2 步階加載行為...................................... 96

7.1.3 循環負載行為...................................... 98

7.1.4 複雜負載行為..................................... 101

第八章結論與未來研究方向............................... 105

8.1 結論............................................... 105

8.2 未來研究方向....................................... 106

參考文獻............................................... 107

附錄 修正 Armstrong-Frederick 本構模型潛變計算程式..... 113

自述................................................... 117

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