覆晶構裝疲勞壽命與無鉛銲料可靠度評估

Fatigue Life of Flip-Chip Package and Reliability Evaluation of Lead-Free Solder

邱建嘉(Chien-Chia Chiu)

指導教授 ： 鍾文仁

中原大學/工學院/機械工程研究所/碩士(2004年)

https://doi.org/10.6840/cycu200400554

摘要

本文針對覆晶構裝體在環境溫度循環負載之下，利用有限元素分析軟體模擬覆晶構裝體之熱及機械行為。結果顯示，元件間材料性質的差異，為造成構裝體變形的主因；就錫球部分而言，最大等效應變範圍值均發生在離模型中心最遠處(構裝體最外側錫球與晶片接合面處)，也是最容易造成疲勞破壞處。在可靠度分析上，考慮多種不同的幾何對稱模型，依-55～125℃之熱震試驗(Thermal Shock Test)模擬，以疲勞-應變方法計算其疲勞壽命並進行比較。此外，由於錫球之材料為錫鉛合金，鉛是具毒性材料，大量使用將造成嚴重的環境污染，在不久的將來會全面禁止使用，無鉛材料的崛起與重要性是顯而易見的，因此，本文亦對無鉛材料之特性與可靠度做整理與探討。
文章第一部分以彈塑性材料模型加上潛變效應，模擬覆晶構裝中錫球之材料行為，探討不同的幾何對稱模型對這些行為與效應所產生的差異性，並使用田口方法，找出錫球對疲勞壽命的最佳幾何形狀；第二部分則依無鉛材料的特性，沿用第一部份之覆晶構裝模型來進行無鉛錫球的可靠度評估。

關鍵字

熱震試驗 ； 疲勞壽命 ； 田口方法 ； 有限元素分析 ； 無鉛錫球

並列摘要

This study focuses on the reliability of flip chip package under the loading of cyclic temperature. The Finite Element Analysis code is used to simulate the thermal conduction and the mechanical behavior of flip chip package. The results reveal that the deflection is caused by the difference of material properties of the components, as such, the maximum equivalent strain of solder bumps always happens at the farthest place from the symmetrical surface of models where the fatigue destruction occurs most easily.
Further, thermal shock test (TST) in the temperature range of -55～125 ℃ was employed to study issues of reliability in several kinds of symmetrical models. The fatigue life was calculated by fatigue-strain method. Moreover, the material of solder ball is tin-lead alloy. Lead is a poisonous material that causes serious environment pollution when used in a great quantity, and it will be forbad presently. The importance of lead-free material is evident, and therefore the characteristic and reliability of lead-free material are also discussed in this study.
In the first part of this study, the elastic-plastic-creep model is considered to simulate the material behavior of solder ball in Flip Chip package, and the diversity among the different symmetrical models are discussed. Taguchi method is used to find the optimum geometry of solder ball for gaining the best fatigue life. The Flip Chip model in the first part is also used in the second part to estimate the reliability of lead-free solder.

並列關鍵字

Lead-Free solder ； Taguchi method ； Finite Element Analysis ； Thermal Shock Test ； Fatigue Life

參考文獻

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