錫鉍共晶及添加鉍之錫球接點界面之研究

The Joint Interface Study of Sn-Bi Eutectic and Bi-doped Lead-Free Solder

林彥甫(Yan-Fu Lin)

指導教授 ： 高振宏

國立臺灣大學/工學院/材料科學與工程學研究所/博士(2020年)

https://doi.org/10.6342/NTU202002715

摘要

本實驗係研究Sn-58Bi (wt.%)錫鉍共晶以及Sn-0.7Cu-0.05Ni-2Bi (wt.%)鉍添加無銀錫球與無電鍍鎳鈀金(ENEPIG)基材之界面反應與接合行為；並探討回焊以及熱處裡之界面介金屬化合物顯微組織與進行剪應力推球測試。
Sn-58Bi錫鉍共晶以及無電鍍鎳鈀金的回焊接合界面上可以發現稜鏡形狀的(Pd,Au)Sn4介金屬和一薄層Ni3Sn4介金屬。當回焊時間到達1小時會發現有多邊形不連續的Ni3Sn4 介金屬在接合界面形成；當回焊時間拉長到5小時，Ni3Sn4介金屬則會形成連續的結構於接合界面；而當回焊時間大於500小時，鎳扮演的擴散緩衝層因為已經因為熔解於錫球與介金屬之中失去緩衝作用，錫鉍與銅基材的反應生成(Cu,Ni)6Sn5 以及Cu3P 在介面上。而這些介金屬主要來自於錫鉍與鎳磷以及銅基材於熱反應所得到的結果。而在推球實驗中發現回焊時間拉長到500小時到1500小時之間沒有明顯的剪切強度弱化。
在固溶強化的Sn-0.7Cu-0.05Ni-2Bi與無電鍍鎳鈀金的接合界面上，可以發現(Cu,Ni)6Sn5跟(Ni,Cu)3Sn4的介金屬化合物；當即使熱處理長達1500小時，介金屬的厚度也沒有明顯的改變。推球剪切強度實驗也發現即使熱處理1500小時，錫球接合強度維持60 MPa的推力。

關鍵字

錫鉍共晶 ； 無電鍍鎳鈀金 ； 界面反應 ； 剪切強度 ； 固溶強化

並列摘要

In this study, we investigated solder balls made of eutectic Sn-58Bi (wt.%) and Sn-0.7Cu-0.05Ni-2Bi (wt.%) that were jointed to a printed circuit board substrate with a metal finish by using electroless nickel electroless palladium immersion gold (ENEPIG). We evaluated the interfacial reactions and mechanical properties of the solder joints of Sn-58Bi and Sn-0.7Cu-0.05Ni-2Bi with ENEPIG after aging at 175°C.
Prism-type (Pd,Au)Sn4 and thin-layer Ni3Sn4 intermetallic compounds (IMCs) were formed at the interfaces of the Sn-58Bi/ENEPIG joints after reflow. After reflowing at 175°C for 1 hr, discontinuous polygonal Ni3Sn4 IMCs were formed at the interfaces of the Sn-58Bi/ENEPIG joints. During 5-hr reflowing, the Sn-58Bi/ENEPIG interfacial IMCs changed to continuous Ni3Sn4. As the reflowing time increased to 500 hr, (Cu,Ni)6Sn5 and Cu3P IMCs formed at the Sn-58Bi/ENEPIG interface. The interfacial product variation resulted from the preferential Cu consumption from the solder and continuous Ni diffusion from the Ni(P) layers. In ball shear test result, the shear strength of the Sn-58Bi/ENEPIG interface was stable even after an aging time of 1500 hr.
On the other part, IMCs of (Cu,Ni)6Sn5 and (Ni,Cu)3Sn4 IMCs were formed in the jointed interface of ENEPIG and strengthened solid solution of the solder alloys, Sn-0.7Cu-0.05Ni-2Bi. No obvious IMC thickness change was observed until after aging for 1500 hr. Moreover, the ball shear strength of the Sn-0.7Cu-0.05Ni-2Bi/ENEPIG solder joint remained stable at approximately 60 MPa after 1500-hr aging.

並列關鍵字

Eutectic Sn-58Bi ； ENEPIG ； Interfacial reactions ； Shear strength ； Solid solution strengthening

參考文獻

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