助焊劑殘留對覆晶封裝底膠材料性質影響之研究

The Effects of Flux Residues on Properties of Underfill Materials for Flip Chip Package

林希耘(Hsi-Yun Lin)

指導教授 ： 洪信國

元智大學/工程學院/化學工程與材料科學學系/碩士(2011年)

摘要

本實驗是利用已商業化之底膠材料與助焊劑，探討助焊劑殘留對覆晶封裝底膠材料性質之影響。比較不同助焊劑殘留量的底膠材料，在熱安定性、吸濕性、機械性質及硬化反應的差異。經由實驗果發現；與不含助焊劑之純底膠材料相比，以DSC分析材料玻璃轉移溫度，發現助焊劑殘留量增加，會有使此底膠材料玻璃轉移溫度下降。硬化動力分析結果發現，助焊劑會參與底膠硬化反應及改變其反應基構。以TGA分析，發現助焊劑殘留量增加影響其最大裂解溫度，使其略為下降。以三點彎曲測試其機械性質強度，則彎曲強度會隨著助焊劑殘留量增加而減低，且其吸濕性則有增加的趨勢。底膠材料性質之改變，會進而影響封裝完成之後的電子元件的信賴性，產生可靠度失效的疑慮。

關鍵字

底膠材料 ； 助焊劑 ； 吸濕性 ； 活化能 ； 硬化反應

並列摘要

The effects of flux residues on the premature failure of underfill epoxy materials used in flip chip packages are investigated by using the solder bump stress analysis, moisture absorption test, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and flexural test. It is obtained from the moisture absorption and flexural tests that the water content of the underfill epoxy increases but the flexural strength of which decreases with increasing the content of flux residues in the epoxy, and which are responsible for the premature fracture of the solder bump. The results of DSC indicate that the flux residues can affect the curing kinetics and mechanism, i.e., the reaction order, activation energy, and frequency factor, of the epoxy during the cure. Henceforth, the curing rate and glass transition temperature of the epoxy significantly decrease in the presence of a small amount of flux residues. Moreover, it is confirmed by TGA that the thermal stability of the cured epoxy would be adversely affected by the residual flux.

並列關鍵字

curing kinetics ； DSC ； premature failure ； epoxy underfill ； flux residues ； cure ； solder bump

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