隨機振動與熱效應複合負載下之封裝體錫球應力預測分析

Solder Ball Stress Prediction Analysis for Package with Compound Loadings of Random Vibration and Thermal Effect

梁秀瑋(Xiu-Wei Liang)

指導教授 ： 王栢村

國立屏東科技大學/工學院/機械工程系所/碩士(2010年)

https://doi.org/10.6346/NPUST.2010.00127

摘要

透過可靠且準確之印刷電路板分析模型便可預測結構於衝擊、振動甚至具熱效應模擬情況下系統之響應。本文利用實驗模態分析方法及有限元素軟體所建構之有限元素模型進行模型驗證。首先將自由邊界狀態下之印刷電路板封裝體表面貼附加熱片模擬晶片發熱情況，印刷電路板整體架構可細分為晶片、基板、封膠及錫球，對印刷電路板具熱效應進行溫度場分析可得其溫度分佈及所受熱應力，再對印刷電路板於穩態熱效應下進行模態分析可得結構之模態參數，即自然頻率與模態振型，經由實驗模態分析同樣可得到結構系統之模態特性，並以此作為有限元素模型修正之基礎，透過比對理論分析與實際結構之頻率響應函數及模態參數，即可確立此精細模型等效之材料參數及熱邊界設定，再將印刷電路板驗證完成之等效有限元素模型延伸至鎖固邊界進行模型驗證，依循JEDEC制定振動試驗規範進行頻譜響應分析，藉由理論及實驗之加速度功率頻譜密度函數比對驗證，可確認此印刷電路板精細模型正確性，並進一步預測印刷電路板在具熱效應與振動測試耦合狀態下之疲勞破壞。本文建立振動與熱傳耦合驗證分析流程，並對印刷電路板具熱效應於隨機激振下疲勞破壞評估，由本文所建立分析方法將有利於未來印刷電路板於振動與熱傳耦合負載下之設計分析。

關鍵字

印刷電路板 ； 模型驗證 ； 熱傳分析 ； 隨機振動 ； 響應預測

並列摘要

A reliable and accurate analytical model is desired for the printed circuit board (PCB) with IC package to predict the system response due to loadings such as shock and vibration simulation or even with thermal effect. This work addresses the procedure of model verification by the adoption of experimental modal analysis (EMA) to validate the finite element (FE) model constructed by FE commercial software. The PCB with one package adhered with the heating pad to emulate the heat effect is first considered for completely free boundary condition. The refined FE model of the PCB consists of detail components, such as the chip, substrate, compound and solder balls. The thermal effect on the PCB is simulated to conduct the temperature field analysis as well as the thermal stress. The modal analysis on the PCB with the heating in steady state is then performed to obtain the structural modal parameters, i.e. natural frequencies and mode shapes. The EMA is also carried out to determine the system modal properties that are used to update the analytical FE model. Through the comparison of frequency response functions and modal parameters between the analytical FE model and the real PCB structure, the refined FE model can be verified for material properties and thermal boundary conditions. The same procedure for model verification is then conducted via both EMA and FEA on the PCB in the fixed boundary that complies with the test fixture for the random vibration test of JEDEC specification. The verified equivalent FE model of the PCB can then be adopted to perform spectrum response analysis according JEDEC random vibration test specification. The acceleration power spectral density (PSD) spectrum obtained from FEA is compared and shown good agreement with the experimental results. The stress prediction on the components of PCB can then be evaluated for possible failures due to both thermal effect and random excitation. This work lays out the procedure to validate the analytical model, in particular for the PCB with the IC package in details considering the thermal effects. The response prediction of the PCB subjected to random vibration input with thermal effect is performed to evaluate the component failure. The developed methodology will be beneficial to the design analysis of PCB, in particular for coupling loadings of thermal effects and random excitations.

並列關鍵字

PCB ； model verification ； temperature analysis ； random vibration ； response prediction

參考文獻

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