界面強度模擬於三維晶片堆疊電子封裝與四點彎折界面強度測試之應用

Application of Interfacial Strength Simulation in Three-Dimensional Chip Stacking Electronic Packaging and Four-Point Bending Delamination Test

吳仲融(Chung-Jung Wu)

指導教授 ： 江國寧

國立清華大學/工學院/動力機械工程學系/博士(2010年)

摘要

本研究由界面強度模擬的觀點，探討三維晶片堆疊封裝之完整可靠度分析，以及四點彎折脫層試驗之改良。在可靠度分析中，除了典型的錫球壽命與晶片裂片分析，並引進破裂力學進行銅凸塊間裂縫分析，以及討論銅矽穿孔與銅凸塊結構之壽命。此外，本研究採用改良型虛擬裂縫閉合法(Modified Virtual Crack Closure Technique, MVCCT)與有限單元法(Finite Element Method, FEM)之破裂分析，應用於計算四點彎折脫層試驗之界面脫層行為，並提出修正試片尺寸與部份接合效應之方法。對於四點彎折試驗分析，本研究提出應用於有限單元模型之外力固定邊界條件設定，並加以驗證。此外，試片尺寸效應之修正亦藉由模擬預估與實驗驗證來進行推導；而為達到增加極限界面能量釋放率之量測範圍，本研究提出之部份接合效應亦被證實。基於四點彎折脫層試驗之解析解，本研究推導用於修正試片尺寸效應與部份接合效應之數學模型。
根據在四點彎折試驗分析中對於MVCCT之應用與驗證，本研究將其進一步應用於三維封裝結構之破裂力學分析，使用之測試載具主要由銅導通孔、銅凸塊與ABF層壓物結構所構成。針對由真實三維封裝結構中觀察得到存在於兩連接銅凸塊間的孔洞脫層結構，利用前述方法可加以評估於封裝層級該孔洞脫層擴張的可能性。藉由以模擬得到之界面能量釋放率數值，與文獻所記載之極限值交互比較，可驗證該脫層結構不會發生擴張；相同的分析方法亦應用於層板級之三維封裝結構中，並得到與封裝層級分析相同之結果。此外，本研究提出三種根據測試載具為基礎所設計之三維封裝結構，以探討三維封裝結構於實際量產之可行性，包含錫球壽命、銅導通孔與凸塊壽命、以及晶片裂片分析被同時應用於模擬分析當中。結果顯示應用了技術成熟之打線(Wire Bonding)方法與塑膠球陣列封(Plastic Ball Grid Array, PBGA)裝技術之設計，展現出較佳的綜合可靠度壽命。

關鍵字

三維晶片堆疊封裝 ； 四點彎折 ； 界面強度 ； 界面能量釋放率 ； 修正虛擬裂縫閉合法 ； 有限單元法

並列摘要

From the viewpoint of interfacial strength simulation, an overall reliability analysis of three-dimensional (3D) chip stacking package and the modification of the four-point bending (4PB) delamination test were investigated in this research. In the reliability analysis, aside from typical solder joint life prediction and die-crack analysis, fracture mechanics was introduced for crack examination between copper bumps, as well as copper through silicon via (TSV) and bump life prediction. Moreover, fracture analyses based on modified virtual crack closure technique (MVCCT) and finite element method (FEM) were carried out to evaluate the delamination behavior in the 4PB delamination test, and the modification for specimen size and partially-adhesive effects were proposed. For the 4PB delamination test analysis, the controlled-force loading condition for FEM models was proposed and validated. Besides, the modification for the size effect was derived through simulation predictions and experimental validation. Moreover, to broaden the critical energy release rate (Gc) measuring range when using the same substrate, the concept of partially-adhesive sandwich specimen was developed and validated. The modified equations based on the analytical solution for 4PB delamination tests were derived as well.
Based on the application and validation of MVCCT in the 4PB test analysis, the former was further utilized in the fracture analysis of the 3D package. The test vehicle was mainly composed of copper TSV and bumps, and the ABF (Ajinomoto Built-up Film) lamination structure was designated. According to the vacancy observed in an actual package structure, the embedded delamination between two connecting copper bumps was evaluated to investigate the possibility of delamination expansion for the 3D package at the package level. By validating the simulation G value with the Gc value reported in literature, the delamination expansion should not happen. Moreover, the simulation procedure was performed to predict fracture behavior for the 3D package at the board level, and the results show the same conclusion as that for the package level case. In addition, three kinds of 3D package designs based on the test vehicle were developed to investigate the feasibility of mass production. In this research, several reliability issues including solder joint life, copper TSV and bump life, and die-crack were evaluated through FEM analysis for comparison between each case. The results reveal that the proposed 3D chip stacking package combined with well-developed wire-bonding and plastic ball grid array (PBGA) packaging technology yielded a relatively better performance reliability.

並列關鍵字

3D chip stacking package ； four-point bending (4PB) ； interfacial strength ； energy release rate ； modified virtual crack closure technique (MVCCT) ； finite element method (FEM)

參考文獻

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