本研究選用五種當前廣泛被使用的無鉛銲料，Sn、Sn-3.0Ag-0.5Cu、Sn-0.7Cu、Sn-58Bi、Sn-9Zn，與Au/Ni/SUS304基材於反應溫度240、255、270℃，分別進行不同反應時間1-5小時的液/固界面反應，探討其界面反應之後介金屬相種類、反應機制、反應動力學、成長速率常數與反應活化能。

實驗結果顯示，Sn/Au/Ni/SUS304以及Sn-58Bi/Au/Ni/SUS304反應偶中，界面處的介金屬相主要為Ni3Sn4相生成，其界面處Ni層依然保留完整的阻障。Sn-3.0Ag-0.5Cu/Au/Ni/SUS304反應偶中，因銲料中Cu濃度為0.5 wt.%，界面處的介金屬相主要為(Cu,Ni)6Sn5相與(Ni,Cu)3Sn4相生成；Sn-0.7Cu/Au/Ni/SUS304反應偶中，因銲料中Cu濃度為0.7 wt.%，界面處的介金屬相主要為(Cu,Ni)6Sn5相。隨著反應時間增加溫度上升，其界面處Ni層消耗殆盡，同樣觀察到界面處發生大規模剝離現象。不同的是SAC/Au/Ni/SUS304反應偶，因界面處有未剝離的(Ni,Cu)3Sn4相，導致銲料無法與SUS304基材界面反應；而SC/Au/Ni/SUS304反應偶，銲料與SUS304基材界面反應，生成另一介金屬相為FeSn2相。

Sn-9Zn/Au/Ni/SUS304反應偶中，Zn原子活性較高且容易在界面上聚集，故容易與基材上的Ni層反應生成Ni5Zn21相。同樣的隨著時間拉長及溫度上升，Ni5Zn21相成長Ni層消耗，其Ni層依然保留完整阻障。四個反應偶的介金屬相總成長厚度與反應時間呈現拋物線關係，故反應機制亦應為擴散控制所主導。

This study investigates the interfacial reactions between five kinds of lead-free solders, Sn, Sn-3.0Ag-0.5Cu (wt.%), Sn-0.7 wt.%Cu (SC), Sn-58 wt.%Bi (SB) and Sn-9 wt.%Zn (SZ), and Au/Ni/SUS 304 substrates. The reaction temperatures were at 240, 255 and 270℃, and the reactions times were varied between 1 to 5 hours. The surface morphology is examined by optical-microscopy (OM), scanning electron microscopy (SEM). The intermetallic compound (IMC) composition was determined by SEM with energy dispersion spectrometer (EDS) and electron probe micro-analyzer (EPMA). Then, the composition data compared with related phase diagrams to indentify the IMC formed at the interface.

According to experimental results, in the Sn/Au//Ni/SUS304 couple, only one oval-type and polyhedron-type IMC layer was found at the Sn/Au/Ni/SUS304 interface. It was the Ni3Sn4 phase of Sn-41.1 at.% Ni. only one IMC layer with composition of Sn-31.7Cu-23.3Ni (at.%) was found in the SC/Au/Ni/SUS304 couples. It should be the (Cu, Ni)6Sn5 phase with the hexagonal-type structure. When the Ni layer was completely consumed, the massive spalling of the (Cu, Ni)6Sn5 phase was found in the solder. When the (Cu, Ni)6Sn5 phase was spread over the interface, the SUS304 substrate surface could directly contact the SC solder. Thus, Sn atoms reacted with the SUS 304. The thin layer IMC was formed at the interface, its composition was Sn-25.7 at.% Fe and it should be the FeSn2 phase with the platy-type layer.

In the Sn-3.0Ag-0.5Cu/ Au//Ni/SUS304 couples, there were two IMCs such as (Cu,Ni)6Sn5 phase and (Ni,Cu)3Sn4 phase at the interface. It should be the (Cu, Ni)6Sn5 phase with the hexagonal-type structure. And (Ni,Cu)3Sn4 phase with the ovall-type structure. When the Ni layer was completely consumed, the massive spalling of the IMCs layer was found in the solder. But SUS304 substrate surface could not directly contact the SC solder, beause of (Ni,Cu)3Sn4 phase adherence at interface.

In the SB/Au//Ni/SUS304 couple, only one needle-type IMC layer was found at the SB/Au/Ni/SUS304 interface. It was the Ni3Sn4 phase of Sn-38.3 at.% Ni. The thickness of the Ni3Sn4 layer increased with the time. It reveals that more Ni atoms dissolve into the molten solder and react with Sn atoms to form the Ni3Sn4 phase at the interface. In the SZ/Au//Ni/SUS 304 couple, one pillar-type IMC layer of Zn-18.7 at.% Ni was found and it should be the Ni5Zn21 phase. The thickness of the Ni5Zn21 phase increased with the time. Since the Zn atoms easily penetrated and segregated toward the substrates reacts to form the Ni5Zn21 phase at the interface.

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