摘要电子器件的微型化发展及高密度细间距封装趋势，对主流Sn-Ag-Cu系无铅微焊点的可靠性提出了越来越高的要求。然而Sn-Ag-Cu系无铅焊料合金中Ag的价格比较昂贵，这就使电子产品成本上升，对推进电子产品无铅化不利。因此研究低银含量的无铅钎料势在必行。本试验选用Sn-0。7Cu、Sn-0。3Ag-0。7Cu、Sn-1。0Ag-0。5Cu和高银含量的Sn-3。0Ag-0。5Cu钎料做为研究对象，研究了Ag含量对Sn-Ag-Cu无铅钎料合金在Cu基板上铺展性能以及Sn-Ag-Cu钎料/Cu界面显微组织的影响，研究不同时效条件下Ag含量对Sn-Ag-Cu微焊点剪切力学性能的影响，从而确定不同银含量的Sn-Ag-Cu微焊点的各项性能。试验结果表明，钎料合金中银含量的增加，可以提升部分的铺展率；Ag含量的增加使无铅微焊点的组织结构得到细化，高Ag含量的Sn-Ag-Cu系钎料的剪切力最大，强度较高，也就是随着Ag含量在Sn-Ag-Cu系钎料中比例的增加，剪切力也逐渐增加，使得微焊点的剪切力学性能得到改善与提升。86461

毕业论文关键词：Sn-Ag-Cu；无铅钎料；显微组织；剪切强度

Abstract The miniaturization development of electronic components and the trend of high density and fine pitch packaging have put forward higher and higher requirements on the reliability of lead-free solder joints of mainstream Sn-Ag-Cu system。 However the Ag in Sn-Ag-Cu alloy is expensive, which makes the cost of electronic products rise and promote lead-free electronic products adversely。 Therefore, it is imperative to study the low silver content of lead-free solder。 In this experiment, Sn-0。7Cu, Sn-0。3Ag-0。7Cu, Sn-1。0Ag-0。5Cu and Sn-3。0Ag-0。5Cu solder are selected as the research objects。 we studied the Ag content of Sn-Ag-Cu lead free solder alloy on Cu substrate spreadability and Sn-Ag-Cu solder / Cu interface microstructure effects, The effects of Ag content on the mechanical properties of Sn-Ag-Cu micro solder joints under different aging conditions were studied, and the properties of Sn-Ag-Cu micro solder joints with different silver content were determined。 The test results show that the silver content in the solder alloy increased, which can enhance the spreading rate; With the Ag content increasing, the organizational structure of the lead-free solder joints can be refined。 High content of Ag in the Sn-Ag-Cu solder maximum shear strength。 With the Ag content in the Sn-Ag-Cu solder in proportion increasing, shear force increased gradually, which makes the shear mechanical properties of micro solder joint improved and improved。

Keywords: Sn-Ag-Cu; Lead-free solder; Microstructure; Shear strength

目录

第一章  绪论 1

1。1 引言 1

1。2 球栅阵列封装技术 2

1。3 无铅钎料的要求与发展 3

1。4 Sn-Ag-Cu 系钎料研究现状 4

1。4。1 Sn-Ag-Cu 系钎料简介 4

1。4。2 Sn-Ag-Cu系研究动态 5

1。4。3 Sn-Ag-Cu/Cu焊点组织与力学性能 5

1。5 课题研究的主要内容和意义 6

第二章  试验方法与设备 8

2。1 试验设备和材料 8

2。2 无铅钎料合金的铺展试验 8

2。2。1 试验原理 8

2。2。2 试验方法 9

2。3 焊点显微组织的观察分析 10

2。4 焊点剪切力学性能试验