三維積體電路封裝中錫2.5銀微凸塊的冶金反應之研究

Abstract

隨著電子產業的發展，電子產品紛紛追求高效能、小體積的趨勢發展，3-D IC技術因應而生，而其中微凸塊的接點已經被採用來連接上下層的晶片。本實驗利用錫2.5銀微凸塊搭配Ni/Cu金屬墊層進行迴銲與高溫儲存測試觀察其冶金反應。在260℃下迴銲30分鐘，發現微凸塊幾乎都反應成Ni3Sn4介金屬化合物，而Ni層仍然保持完整的保護著上方的Cu層，使它不與銲錫反應。另一方面，隨著銲錫與Ni反應生成Ni3Sn4，使得銲錫中的Ag濃度上升，造成片狀Ag3Sn的出現。在迴銲與高溫儲存下，Ni3SN4成長速率常數分別為0.45μm/min1/2、0.067μm/hr1/2；而Ni消耗速率常數分別為0.12μm/min1/2、0.018μm/hr1/2。而在銲錫厚度3.53與10.2μm的試片，迴銲10分鐘前的Ni3Sn4平均成長速率為0.214μm/min、0.117μm/min。錫2.5銀銲錫在260℃迴銲10分鐘出現片狀Ag3Sn的臨界體積為1088.03μm3。

In this thesis, we study the metallurgical reactions at liquid state and solid state for Sn2.5Ag microbumps with Cu/Ni UBM. 260℃reflow 30 min, the microbumps almost became the Ni3Sn4 intermetalliccompounds (IMCs). In addition, the dispersed Ag3Sn IMCs would agglomerate to form plate-like Ag3Sn IMCs as the reflow time increased. For the reflow and thermal aging tests, we calculated the growth rate constant of Ni3Sn4 in the reflow and thermal aging test were 0.45μm/min1/2 and 0.067μm/hr1/2, and the consumption rate constant of Ni in the reflow and thermal aging tests were 0.214μm/min and 0.117μm/min, respectively. The critical volume of Sn2.5Ag for plate-like Ag3Sn formation was 1088.03μm3。