金/銅凸塊氮化矽層破裂與Sn-xAg銅柱凸塊剪力之分析研究

本研究共分為兩大項，第一項針對封裝製程中氮化矽層之應力分佈進行分析，主要模型為RDL(Re-distribution line)、Non-bump on array (Non-BOA)、Bump on array (BOA)、Al-Pad Slot四種不同結構之模型，搭配不同的退火溫度、凸塊高度、導角型式等分析條件，模擬封裝結構經過製程流程後之殘留應力(Residual Stress)分佈情形與最大應力點，並分析損壞位置，第二項研究針對銅柱凸塊與不同錫銀比例的銲料在不同迴銲次數後，產生不同厚度的金屬間化合物層，進行推球分析，並以實驗對照模擬分析結果，找出不同迴銲溫度與不同錫銀銲料比例下，對於整體強度之關係，透過此兩大項分析，找出個別主導因素以及最佳製程條件。本論文之模擬分析結果，可觀察到氮化矽層分析中，凸塊的高度、退火溫度對於封裝體的失效影響最為顯著，降低凸塊高度可節省封裝成本及降低凸塊膨脹量，降低退火溫度可減少封裝體產生過大膨脹收縮量，當凸塊高度為9μm以及退火溫度245℃，此條件可視為封裝結構較佳的製程參數，銅柱凸塊分析中，結構強度主要影響因素為迴銲次數，迴銲五次之銅柱凸塊，擁有最好的抗剪能力。

關鍵字

氮化矽；銅柱凸塊；熱應力

並列摘要

The study has two subjects, one subject focuses on the thermal stress of wafer level chip scale package subjected to Si3N4 Cracking for the Au/Cu Bumping Process. The finite element analysis (FEA) method is used to simulate its mechanical behavior and material condition. According to the Residual Stress behavior which calculates the package’s failing situation is considered as the reliability of the whole package. The second subject for Sear Force Analysis Between Sn-xAg/Copper Pillar Interface. This analysis shows the effect of different reflow temperature and different tin-silver ratio on solder strength. Four Si3N4 Cracking models – RDL (Re-distribution line), Non-bump on array (Non-BOA), Bump on array (BOA), and Al-Pad Slot are included to simulate the treatise and calculate the Residual Stress of difference annealing temperature, bump height, and chamfering-type after annealing process. Throughout fully investigation, the Si3N4 Cracking simulation result shows that lower bump height and lower annealing temperature can be regarded as optimal solution. From the Copper Pillar simulation result, reflow 5X copper pillar has the best shear capacity.

並列關鍵字

Silicon nitride ； Copper pillar ； Thermal stress

參考文獻

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金/銅凸塊氮化矽層破裂與Sn-xAg銅柱凸塊剪力之分析研究

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