微量添加元素對錫鉍銲料與銅基板介面反應之影響

Abstract

本研究探討在錫-鉍-銦基銲料中添加不同的合金元素（如鎳、銅、銀與鋅）對其與銅基板之介面反應的影響。對於錫-鉍-銦-(鎳、銅、銀)/銅銲點而言，在迴焊後可在介面觀察到Cu6Sn5介金屬化合物的生成。在等溫時效處理的過程中，Cu6Sn5層持續增厚，導致介面處鉍相顯著累積。由於該富鉍層具高脆性，可能會削弱銲點的剪切強度。相較之下，當添加鋅元素時，錫-鉍-鋅/銅介面會生成Cu5Zn8介金屬。由於Cu5Zn8的生長並不消耗錫，因此能有效抑制時效處理過程中鉍的聚集。 根據上述結果，錫-鉍-鋅與錫-鉍-銀-鋅被視為具發展潛力的合金材料，值得進一步探究。本研究進一步以小尺寸銲球評估錫-鉍-鋅與錫-鉍-銀-鋅銲點於攝氏120度等溫時效處理後的介面反應與機械性質。然而，在高溫條件下，含鋅銲料出現嚴重的氧化現象，氧化反應深入銲球內部及介面，顯著降低銲點的剪切強度。為進一步釐清氧化問題，本研究設計了於不同環境條件下進行高溫時效處理的實驗，包含真空、空氣、油浴爐環境下與包覆底部填充膠的樣品，以探討錫-鉍-鋅銲料的氧化行為。

This study investigates the effects of adding various alloying elements such as Ni, Sb, Cu, Ag, and Zn on the interfacial reactions of Sn-Bi-In-based solder joints with Cu substrates. For the Sn-Bi-In-(Ni, Sb, Cu, Ag)/Cu solder joint, Cu6Sn5 intermetallic compounds (IMCs) were observed at the interface after reflow. During isothermal aging, the Cu₆Sn₅ layer thickened, leading to significant Bi phase accumulation at the interface. The presence of this brittle Bi-rich layer may deteriorate the shear strength of solder joints. In contrast, when Zn was added, Cu5Zn8 formed at the Sn-Bi-Zn/Cu interface. Since the growth of Cu5Zn8 does not consume Sn, it effectively suppressed Bi accumulation at the interface during aging. Based on these results, Sn-Bi-Zn and Sn-Bi-Ag-Zn were identified as two promising candidates for further investigation. We examined the interfacial reactions and mechanical properties of Sn-Bi-Zn, and Sn-Bi-Ag-Zn solder joints using small solder balls after aging at 120 °C. However, high-temperature aging caused severe oxidation in the Zn-containing solders, penetrating both the solder interior and the interfacial region, which significantly reduced the shear strength of the joints. To further investigate this issue, we conducted aging tests under different environmental conditions, including vacuum, air, silicone oil bath, and samples encapsulated with underfill, to examine the oxidation behavior of Sn-Bi-Zn solder.