- 學位論文
覆晶構裝在熱循環負載作用下對疲勞壽命之分析與探討
The Analysis on the Fatigue Life of Flip Chip Package Under Cyclic Thermomechanical Loading
摘要
半導體元件有日益縮小的趨勢，傳統有腳架的構裝方式，也轉變成利用銲球來連接晶片與基材的構裝方法。可靠度對於產品的使用壽命來說是一項非常重要的指標，軟銲接點雖有其優點，但也由於材料及界面的複雜，為了增加構裝的可靠性，有必要對於銲球之熱傳及熱應力分析加以探討，以提供設計及製造之參考。 本文針對覆晶構裝體在環境溫度循環負載之下，利用ANSYS有限元素分析軟體模擬覆晶構裝結構體之熱及機械行為。結果顯示，由於受元件間材料性質差異之影響，使構裝體產生變形。就錫球部分而言，最大應力、應變，亦即最大等效塑性應變範圍值，均發生在離模型中心對稱面最遠處，也是最容易造成疲勞破壞處，並進一步做疲勞分析。 由本文研究結果顯示，由於受到構裝元件材料性質差異之影響，使構裝體最外側錫球與晶片接合面處，會造成疲勞破壞。並針對不同的循環數、不同的材質、不同的製程下，分別以疲勞-應力方法以及疲勞-應變方法計算其壽命。此外，在分析錫球之疲勞壽命時，發現選用3-D模型較2-D模型分析準確。
並列摘要
The components of semiconductor show a tendency of being contracted day by day. The packaging technology with pins is substituted by the solder balls for connecting chips and substrate. The reliability is a very important index for the using-life of products. Although the solder contact has many advantages, its material and interface are complicated. To increase the reliability of packaging, the analyses of the thermal conduction and the thermal stress of solder balls are indispensable to provide references for design and manufacture. This paper focuses on the fatigue failure of the flip chip package under the cyclic loading at ambient temperature. The ANSYS is used to simulate the thermal loading and the mechanical behavior of flip chip package. The results reveal that the deflection is caused by the difference of material properties of the components. For example, the maximum equivalent plastic strain of solder balls always happens at the farthest place from the symmetrical surface of models and causes the fatigue failure. From the results of this study, the different materials of components will result in fatigue failure, which occurs on the connecting surface between the most external solder bump and the chip. Moreover, the fatigue-stress method and fatigue-strain method are used to calculate the fatigue life of different cycles, different materials and different processes respectively. Additionally, the results of 3-D model are more accurate than the results of 2-D model when analyzing the fatigue life of solder bumps.