Microstructure,wetting property of Sn-Ag-Cu-Bi-xCe solder and IMC growth at solder/Cu interface during thermal cycling
来源期刊：Rare Metals2021年第3期
论文作者：Yuan Wang Xiu-Chen Zhao Ying Liu Yong Wang Dong-Mei Li
文章页码：714 - 719
摘 要：The effects of adding small amounts of cerium（Ce） to Sn-3.3 Ag-0.2 Cu-4.7 Bi solder on microstructure,wettability characteristic,interfacial morphology and the growth of interfacial intermetallic compound（IMC） during thermal cycling were investigated by optical microscopy（OM）,scanning electron microscopy（SEM） and solderability tester.It is found that the p-Sn phase,Ag3 Sn phase and Cu6 Sn5 phase in the solder are refined and the wetting force increases.Ce is an active element;it more easily accumulates at the solder/flux interface in the molten state,which decreases the interfacial surface energy and reduces the driving force for IMC formation on Cu substrate;therefore,the thickness of IMC at the solder/Cu interface decreases when appropriate Ce was added into the solder.Moreover,the Ce-containing solders have lower growth rate of interfacial IMC than solders without Ce during the thermal cycling between-55 and 125℃.When the Ce content is 0.03 wt% in the Sn-3.3 Ag-0.2 Cu-4.7 Bi solder,the solder has the best wettability and the minimum growth rate of interfacial IMC layer.
Yuan Wang1，Xiu-Chen Zhao1，Ying Liu1，Yong Wang1,2，Dong-Mei Li2
1. School of Materials Science and Engineering,Beijing Institute of Technology2. Center of Packaging and Testing,Beijing Microelectronics Technology Institute
摘 要：The effects of adding small amounts of cerium（Ce） to Sn-3.3 Ag-0.2 Cu-4.7 Bi solder on microstructure,wettability characteristic,interfacial morphology and the growth of interfacial intermetallic compound（IMC） during thermal cycling were investigated by optical microscopy（OM）,scanning electron microscopy（SEM） and solderability tester.It is found that the p-Sn phase,Ag3 Sn phase and Cu6 Sn5 phase in the solder are refined and the wetting force increases.Ce is an active element;it more easily accumulates at the solder/flux interface in the molten state,which decreases the interfacial surface energy and reduces the driving force for IMC formation on Cu substrate;therefore,the thickness of IMC at the solder/Cu interface decreases when appropriate Ce was added into the solder.Moreover,the Ce-containing solders have lower growth rate of interfacial IMC than solders without Ce during the thermal cycling between-55 and 125℃.When the Ce content is 0.03 wt% in the Sn-3.3 Ag-0.2 Cu-4.7 Bi solder,the solder has the best wettability and the minimum growth rate of interfacial IMC layer.
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