覆晶銲錫凸塊高度對無鉛銲錫電遷移破壞時間及破壞模式之影響

Abstract

隨著產品追求輕薄短小的趨勢，覆晶封裝技術也有微小化的趨勢；因此本研究將討論銲錫球高度下降的時候，對電遷移試片可靠度的影響；我們製備了兩組試片：有相同的結構但銲錫接點高度不同，銲錫球高度分別為75μm的高銲錫球，與25μm的低銲錫球。分將他們放置於150℃之加熱板上通以0.9A的電流，使用四點量測紀錄電子流向下的銲錫球之電阻，並定義破壞時間為當電子流方向向下的銲錫球之電阻上升20%為破壞。經過電遷移測試我們發現高銲錫球有較長的平均破壞時間。造成此差異的原因將在本研究中有詳盡的探討。

As the size of the microelectronic devices continues to shrink, the size and the bump height of solder joints continue to decrease. Effects of bump height on electromigration failure time and failure modes have not been studied for Pb-free SnAg solder joints. In this study, we fabricated two kinds of solder joints with different bump heights: low-bump-height (LBH) of 25 μm, and high-bump-height (HBH) of 75μm. Both sets of solder joints were subjected to electromigration tests by 0.9A at 150℃. We measured the changes of bump resistance with Kelvin bump probes. We define the bump failure when the bump resistance increased 20％ of its initial value. According to the temperature results measured by infrared microscope, we found different Joule heating increase in the two solder joints, is responsible for the difference in failure time.