多晶片模組的熱應力分析

多晶片模組經過熱循環負載後，因為各元件材料係數上的差異，會產生翹曲變形、應力與應變集中等現象。就整體多晶片模組而言，應力與應變主要集中在錫球的周圍，且應力、應變集中的地方即是最容易產生破壞的地方。因此，本文利用有限元素分析軟體ANSYS針對多晶片模組加以分析。由模擬結果發現，雖然在變形與錫球應力方面傳統含鉛錫球的表現較好，但與無鉛錫球也相差不多，而疲勞方面的表現卻是無鉛錫球較為優良，所以無鉛錫球在未來大量用於電子構裝的可行性很高。此外也試著改變多晶片模組各材料的參數，如錫球的大小、基板的厚度、晶片間的位置等，希望藉此可找出較佳的方法使得錫球不容易產生破壞。結果顯示，晶片位置對整體多晶片模組的變形、錫球的應力與應變各方面都有影響，但是影響不大，可以忽略不計。而晶片錫球尺寸的大小方面，當錫球半徑增大時，變形量、應力與應變都隨之增加，但錫球內部的應力變化則相反的變小。因此，晶片錫球的尺寸小一點比較好，但也不宜過小，而造成錫球內部的應力變大。基板尺寸的影響方面，當基板厚度增加時，整體的變形量就會變小，但是對錫球應力及應變的影響卻非常小。所以，基板宜保持適當的厚度以減少多晶片模組的變形量增加。

關鍵字

多晶片模組；有限元素分析；亞蘭德模型；熱加速循環；無鉛錫球

並列摘要

In a multi chip module, the material parameters of each element are different so that deflection, stress and strain concentration are happened after the loading of accelerated thermal cycling. Stress and strain concentration happens around the chip solder joints where the multi chip module is easily broken. Thus, a finite element analysis code ANSYS is used to simulate the multi chip module. The simulation results show that fatigue of lead-free solder is better than fatigue of Pb-Sn solder. So it can be expected that lead-free solder will commonly be used in the future. This thesis also tries to change the material parameters of each element and find a way that can make the life of solders longer. The results also show the location of small chip affects less on the stress and strain of solders. By changing the radius of chip solders, deflection, stress and strain are increased when the model has a bigger solder. Although the small solder is better than the big solder, it should be careful that radius of chip solder is not too small to creating the bigger stress in solder. In addition, increasing the thickness of substrate can reduce the deflection but it affects less on stress and strain in the multi chip module. So the thickness of substrate should be kept in a proper value that would not result in a bigger deformation of the multi chip module.

並列關鍵字

Multi Chip Module ； Finite Element Analysis ； Accelerated Thermal Cycling ； Lead-free Solder

參考文獻

[20]邱建嘉，覆晶構裝疲勞壽命與無鉛銲料可靠度評估，碩士論文，中原大學機械工程研究所，2004。

[15]劉振中，無鉛錫球含多層金屬薄膜之晶圓級封裝結構應力分析，碩士論文，國立成功大學工程科學系，台南，2003。

[2]林明池，利用覆晶（Flip Chip）構裝技術開發靜態隨機存取記憶體（SRAM）之多晶片模組（MCM），碩士論文，元智大學化學工程研究所，新竹，2001。

[17]A. Yeo, C. Lee, H. L. Pang, “Flip Chip Solder Joint Fatigue Analysis Using 2D and 3D FE Models,” Thermal and Mechanical Simulation and Experiments in Micro-electronics and Micro-Systems, 2004, pp.549-555.

[3]B. Z. Hong, “Thermal Fatigue Analysis of a CBGA Package with Lead -free Solder Fillets,” Inter Society Conference on Thermal Phenomena, 1998, pp.205-211.

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多晶片模組的熱應力分析

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