摘要传统的Sn-Pb钎料共晶熔点低，导电性能好再加上制作成本低使其在生产中得到了广泛的应用。然而，众所周知，Pb含有剧毒，不论是对环境还是对人们的身体健康都有很大的危害。目前人们致力于发展和传统Sn-Pb钎料性能相近或更好的无铅钎料，以求取代传统Sn-Pb钎料。在目前的电子行业中使用较多的的无铅焊料有Sn-Cu系和Sn-Ag-Cu系，低银Sn-Ag-Cu无铅钎料成为当下热门的研究课题。本实验以Sn-1。0Ag-0。5Cu无铅钎料为研究对象，在钎料中加入不同含量的In（1%，2%，3%，4%），通过不同时间的时效处理，研究观察未时效的与时效过后的显微组织和力学性能，来探究In对钎料组织和性能的影响规律，以求找到提高钎料的综合性能的方法。实验结果表明，添加In元素之后有效的降低了Sn-1。0Ag-0。5Cu无铅钎料的熔化温度，提高了钎料的润湿性。另外，随着In含量的增加，剪切力持续增加，增加了钎料的抗剪性能。86926

毕业论文关键词：Sn-Ag-Cu-In；无铅钎料；显微组织；力学性能；

Abstract Because of it’s low eutectic melting point, electrical conductivity and low cost, etc。 Traditional Sn-Pb solder had been widely used。 However, Pb is highly toxic substances and it has bad effect on humans and the environment。 With the strengthening of environmental awareness, Sn-Pb is bound to be replaced by similar or better performance lead-free solder。 Currently, Sn-Cu system and Sn-Ag-Cu system lead-free solder applied frequently in the electronics industry, low silver Sn-Ag-Cu solder has become a hot research topic。 This work choose Sn-1。0Ag-0。5Cu solder as experimental material, adding different amount of In(0。1%,0。2%,0。3%,0。4%)into it。 Through aging at different time, investigation is performed on the effect of unaged and after aging microstructure and mechanical properties, we want to explore In on the influence of microstructure and properties of solder, in order to improve overall performance。 The results show that the addition of In element effectively reduces the Sn-1。0Ag-0。5Cu lead-free solder melting temperature and improve the solder wettability。 In addition, with increasing In content, shear force continued to increase and increase the solder shear behavior。

Keywords: Sn-Ag-Cu-In; Lead-free solder; Microstructure; Mechanical Properties;

目录

第一章绪论 1

1。1 钎料的无铅化进程 1

1。2 表面贴装技术概述 2

1。3 无铅钎料研究 4

1。3。1 无铅钎料的技术要求 4

1。3。2 Sn-Ag-Cu系无铅钎料特点及发展现状 5

1。5 本研究主要内容 8

第二章实验方法 9

2。1 实验材料 9

2。2 钎料合金的熔化温度实验 9

2。3 钎料合金的润湿铺展实验 9

2。4 时效处理 10

2。5 微焊点力学性能实验 11

2。5。1 BGA表面贴装 11

2。5。2 焊点剪切实验 12

2。6 钎料合金显微组织分析 13

第三章实验结果及分析 15

3。1钎料合金熔化温度实验结果及分析 15

3。2 钎料合金润湿铺展实验结果及分析