- 學位論文
利用田口法分析對PBGA封裝體之錫球的可靠度影響
The Reliability of the Solder Joints in PBGA Package by Taguchi Method
摘要
本研究首先引用文獻來做一連串的比對驗證，以確保本文研究內涵的可信度，然後再利用有限元素軟體(ANSYS)探討IC封裝之無鉛銲錫(95.5Sn-3.9Ag-0.6Cu)在溫度循環負載作用下之每個循環的累積潛變應變與累積潛變應變能密度的特性，進一步配合田口方法，分析IC封裝模型受到溫度循環設計下對疲勞壽命的影響；於此，規劃五個主要之溫度負載因子分別為高溫恆溫溫度、低溫恆溫溫度、升降溫率、高溫恆溫時間和低溫恆溫時間，各因子具有四個水準，依據田口法中的L16直交表，以三種不同IC封裝體PBGA-256、PBGA-388和CCGA-1657作為干擾因子，並運用Schubert與Dudek兩位學者依其實驗所推導的疲勞壽命公式，將求得之疲勞壽命數用田口方法及ANOVA分析比較，找出無鉛錫球在受溫度循環作用下的主要影響因子，探討溫度循環因子對無鉛銲錫之疲勞壽命與可靠度的影響。第二部分針對裂縫錫球進行溫度循環測試，一開始以有限元素分析軟體(ANSYS)模擬3D裂縫錫球在溫度循環負載下的熱機械特性分佈情況；接著進一步配合田口實驗法設計出不同幾何尺寸之錫球，探討錫球幾何尺寸對錫球裂縫增長率的關係，依據田口法L9直交表，規劃了4個錫球幾何因子分別為錫球上圓直徑尺寸、錫球下圓直徑尺寸、錫球高度及錫球最大直徑尺寸，每個因子各具有三個水準值，並以無鉛銲錫(95.5Sn-3.9Ag-0.6Cu與96.5Sn-3.5Ag)及有鉛銲錫(62Sn-36Pb-2Ag)作為干擾因子，最後使用Lau所推導之裂縫增長率公式，以裂縫增長率之數據作ANOVA分析後，找出在設計錫球時錫球幾何參數對裂縫增長之影響，並找出最佳化參數與原始設計之錫球幾何作比較，以期望未來在制定無鉛銲錫之溫度循環測試規範(Criteria)的參考資訊，以及在設計封裝小型化之錫球階段能提供具有效益的資訊。
並列摘要
Firstly, finite element analysis software (ANSYS) is used to investigate the accumulated creep strain range and accumulated creep stain energy density properties of the lead-free solder (95.5 Sn-3.9 Ag-0.6 Cu) in IC packages under the temperature cyclic loading by the Garofalo-Arrhenius hyperbolic sine law. Then, the Taguchi method is further used to analyze the effects of the IC package on the fatigue life subjected to the temperature cyclic loading. The five main factors are the high and low temperature dwells, the temperature ramp rate, and the dwell time of both high and low temperatures, respectively. Moreover, each factor has four levels. According to the L16 orthogonal arrays of the Taguchi method, three different IC packages PBGA-256, PBGA-388 and CCGA-1657 are used as the noise factors. Furthermore, the Schubert’s model is used in Taguchi method and the purpose of ANOVA analysis is to find the main influence factors on the fatigue life and reliability of the lead-free solders. It is thus expected to provide reference data for the setting lead-free solder temperature cycle testing criteria in the future. Secondly, the purpose is aimed to investigate temperature effect on crack solder ball. It uses ANSYS to simulate the 3D crack solder ball under the temperature cyclic loading. Then, cooperating with Taguchi method to design various geometrized size of solder ball and discuss the relation between the geometrized size and the crack growth rate of solder ball. According to L9 orthogonal arrays, 4 solder ball geometrized factors are studied, which are upper round diameter size of the solder ball, lower round diameter size of the solder ball, the height of the solder ball and the biggest diameter size of the solder ball. There are three levels are used on each factor and using 95.5Sn-3.9Ag-0.6Cu, 96.5Sn-3.5Ag,and 62Sn-36Pb-2Ag as noise factor. Finally, we use the crack growth rate which Lau used to find out the effect of geometry parameter on the crack growth. To set up the information of temperature cyclic test standard of lead-free solder and supply useful information to the stage of packaging miniaturization, are compared the best design and the original design of solder ball geometry are compared.
參考文獻
延伸閱讀
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