Study on the interfacial reactions of Ti/AlN joints

Based on the phase equilibrium calculation of the Ti-Al-N ternary system,the interfacial reactions and the phase formation sequences between different types of joints,(Ti matrix)/(AlN particles),(Ti particles)/(AlN plate),and (Ti plate)/(AlN plate),were analyzed theoretically under the reported experimental conditions.Different phase formation sequences for the three kinds of Ti/AlN joints were obtained.It proved that the different phase sequences of both the phase formation sequences and the apparent spatial phase sequences are dominated by the relative amounts and the distribution of the two pairs in the diffusion couples.The theoretical prediction can explain the experimental observations well.     

Ni元素对Sn2.5Ag0.7Cu0.1RE/Cu无铅微焊点界面IMC和力学性能的影响

以Sn2.5Ag0.7Cu0.1RE无铅钎料为研究对象,借助扫描电镜和X衍射等检测方法研究了Ni元素对Sn2.5Ag0.7Cu0.1RE/Cu无铅微焊点界面IMC和力学性能的影响.结果表明,添加适量Ni元素能显著细化Sn2.5Ag0.7Cu0.1RE钎料合金初生β-Sn相和共晶组织,抑制焊点界面区(Cu,Ni)6Sn5金属间化合物的生长和表面粗糙度的增加,提高无铅焊点抗剪强度.当Ni元素添加量为0.1%时,钎料合金组织细小均匀,共晶组织所占比例较多;焊点界面IMC薄而平整,(Cu,Ni)6Sn5颗粒尺寸小,对应焊点抗剪强度最高为45.6 MPa,较未添加Ni元素焊点提高15.2%.     

Sn5Sb1Cu0.1Ni0.1Ag/Cu(Ni)焊点的抗时效性能

采用扫描电镜(SEM)研究在150 ℃等温时效下Cu/Sn5Sb1Cu0.1Ni0.1Ag/Cu与Ni/Sn5Sb1Cu0.1Ni0.1Ag/Ni焊点的界面扩散行为. 结果表明,在时效过程中,随着时效时间的增加,Cu/Sn5Sb1Cu0.1Ni0.1Ag/Cu焊点界面金属间化合物(intermetallic compound,IMC)形貌由开始的细针状生长为棒状,IMC层厚度增加,界面IMC主要成分为(Cu,Ni)₆Sn₅. Ni/Sn5Sb1Cu0.1Ni0.1Ag/Ni焊点的界面IMC形貌由细小突起状转变为较为密集颗粒状,且IMC层厚度增加,界面IMC主要成分为(Cu,Ni)₃Sn₄. 经过线性拟合,两种焊点的界面IMC层生长厚度与时效时间t1/2呈线性关系,Sn5Sb1Cu0.1Ni0.1Ag/Cu界面间IMC的生长速率为7.39 × 10?2 μm2/h,Sn5Sb1Cu0.1Ni0.1Ag/Ni界面间IMC的生长速率为2.06 × 10?2 μm2/h. 镀镍层的加入可以显著改变界面IMC的形貌,也可降低界面IMC的生长速率,抑制界面IMC的生长,显著提高抗时效性能.     

Sn3.0Ag0.5Cu/Cu回流焊点界面化合物尺寸分布特征及生长机制

在电子封装过程中,钎料与基体之间形成金属间化合物层,其主要成分为Cu₆Sn₅,Cu₆Sn₅晶粒的尺寸和形貌特征能够显著影响焊点的服役性能. 采用回流焊的方法制备了一系列Sn3.0Ag0.5Cu/Cu焊点,使用Image-Pro Plus软件对焊接界面化合物Cu₆Sn₅晶粒的尺寸分布和化合物层的厚度进行了统计分析. 结果表明,Cu₆Sn₅的平均粒径正比于t0.38(t为回流时间), 界面化合物层的平均厚度正比于t0.32. 随着回流时间的增加,界面化合物生长速度变慢,Cu₆Sn₅晶粒的尺寸分布更加均匀. 回流时间较长的样品中Cu₆Sn₅的粒径尺寸分布与FRD模型的理论曲线基本相符,而对于回流时间短的样品,晶粒尺寸分布与FRD理论偏离较大. 统计结果显示,出现频次最高的晶粒尺寸小于平均值. 最后讨论了界面Cu₆Sn₅晶粒的生长机制,分析了回流时间对界面Cu₆Sn₅晶粒生长方式的影响.     

界面Ni3Sn4微观形貌演变对微焊点力学性能的影响

针对Ni/(20 μm)Sn/Ni微焊点,研究界面金属间化合物(IMC)Ni3Sn4微观形貌演变及其对微焊点力学性能的影响,并对拉伸断口进行分析。结果表明,随着回流时间增加,Ni3Sn4 IMC厚度快速增加,其形貌也发生显著变化,由短棒状转变成长棒状,最后演变成块状;微焊点的抗拉强度表现为先减小、再持续增大的反常变化趋势,界面Ni3Sn4微观形貌演变成为主导因素,转变成长棒状的Ni3Sn4引起应力集中,造成微焊点的强度降低,继续转变成的块状Ni3Sn4增加了裂纹抗力,提高了抗拉强度。微焊点的断口形貌进一步证实了Ni3Sn4微观形貌演变对微焊点力学性能影响。创新点： 以互连高度为20 μm的Ni/Sn/Ni微焊点为研究对象,通过控制延长回流时间形成以Ni3Sn4 IMC为唯一变量实现其生长的方法,研究了Ni3Sn4 IMC的微观形貌演变对微焊点抗拉强度的影响。     

Cu基板粗糙度对SnAgCu无钎料润湿性的影响

借助电极感应熔化气雾化法,制备了 FeCoNiCrMn高熵合金粉末;通过真空烧结技术,在钢表面制备了具有不同孔隙率和孔径的多孔高熵合金涂层. 研究了不同烧结工艺对多孔涂层孔隙率、孔径以及过渡层厚度的影响. 开展了Al-12Si合金在多孔高熵涂层钢表面的原位润湿铺展试验,探讨了多孔高熵合金涂层对表观接触角和铺展行为的影响规律,深入分析了多孔高熵结构内反应产物的显微组织和相组成. 结果表明,随着烧结温度的升高和保温时间的延长,多孔高熵合金涂层的过渡层厚度逐渐升高,孔隙率及平均孔径逐渐减少. 液态Al-12Si合金液滴在多孔涂层中微通道增强的毛细力作用下,迅速浸润到多孔结构中,并实现了材料表面的完全润湿. 在高熵合金的迟滞扩散效应与高熵效应共同作用下, 界面反应层中金属间化合物的形成受到显著阻碍,界面相结构由富Cr的FCC、富AlFe的BCC以及富AlNi的B2 + 富Al的BCC共晶状结构组成.     

TEM study on the interfacial reaction between electroless plated Ni−P/Au UBM and Sn−3.5Ag solder

This study examined the interfacial reaction between electroless plated Ni−P/Au under bump metallization (UBM) and a eutectic Sn−3.5Ag solder using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The chemical and crystallographic analysis using TEM provided important information on the microstructural evolution at the interface. In this study, UBM was prepared by the electroless plating of Au (0.15 μm)/Ni-15 at %P (5 μm) on a bare Cu substrate and was then reacted with a Sn−3.5Ag eutectic solder at 260°C for various amounts of time to examine the different sequential stages of the interfacial reaction TEM analyses confirmed that beside the Ni₃Sn₄ layer, there were three more IMC layers at the interface: the Ni−Sn−P ternary layer, Ni₃P layer, and the layer of phase mixture of the Ni₃P and Ni₂SnP ternary phases.     

Investigation of interfacial reactions between Sn–Zn solder with electrolytic Ni and electroless Ni(P) metallization

In this study, interfacial reactions of electrolytic Ni and electroless Ni(P) metallization of the ball-grid-array (BGA) substrate with the molten Sn–9Zn (wt.%) eutectic solder alloy were investigated, focusing on the shear strengths and the identification of the intermetallic compound (IMC) phases at various reflow periods. Zn-containing Pb-free solder alloys were kept in molten condition (240 °C) on the bond pads for different durations ranging from 1 to 60 min to render the ultimate interfacial reaction and to observe the consecutive shear strength. After the shear test, fracture surfaces were investigated by scanning electron microscopy equipped with an energy dispersive X-ray spectrometer. Cross-sectional studies of the interfaces were also conducted to correlate with the fracture surfaces. The solder ball shear-load for the Ni(P) system during extended reflow increased with the increase of reflow time. The consumption of the electroless Ni(P) layer in Sn–9Zn was also lower than that of the electrolytic Ni. It was evident that the Sn–Zn solder/electrolytic Ni system was more vulnerable than the Sn–Zn solder/electroless Ni(P) system in high temperature long time liquid state annealing. Sn–Zn solder with electroless Ni(P) metallization appeared as a good combination in soldering technology.     

外能辅助下Sn2.5Ag0.7Cu0.1RE0.05Ni/Cu钎焊接头组织与性能

采用SEM、EDS、XRD等方法研究了超声、电场外能辅助下Sn2.5Ag0.7Cu0.1RE0.05Ni/Cu钎焊接头的组织与性能。结果表明,借助于超声、超声-电场外能辅助能细化Sn2.5Ag0.7Cu0.1RE0.05Ni/Cu钎焊接头钎缝组织并使共晶组织比例增加,界面区金属间化合物(IMC)平均厚度、粗糙度和界面IMC颗粒尺寸减小。超声和电场外能辅助下Sn2.5Ag0.7Cu0.1RE0.05Ni/Cu钎焊接头强度与其界面IMC层粗糙度密切相关,超声的作用更为显著,在超声-电场外能辅助钎焊接头界面IMC层粗糙度降低中占主导作用,施加超声-电场外能辅助下钎焊接头剪切强度与传统钎焊相比提高24.1%;施加超声、超声-电场外能辅助使Sn2.5Ag0.7Cu0.1RE0.05Ni/Cu钎焊接头断裂途径由钎缝和界面IMC层组成的界面过渡区向钎缝侧迁移,呈界面(Cu,Ni)_6Sn_5 IMC解理和钎缝解理+韧窝的脆-韧混合型断裂机制,使接头剪切断口塑性区比例增加,从而提高接头剪切强度。     

Cu基板退火处理的Cu/Sn58Bi/Cu钎焊接头界面微结构

研究了铜基板退火处理对Cu/Sn58Bi界面微结构的影响. 结果表明,在回流以及时效24 h后Cu/Sn58Bi/Cu界面只观察到Cu₆Sn₅. 随着时效时间的增加,在界面形成了Cu₆Sn₅和Cu₃Sn的双金属间化合物(IMC)层,并且IMC层厚度也随之增加. 长时间时效过程中,在未退火处理的铜基板界面产生了较多铋偏析,而在退火处理的铜基板界面较少产生铋偏析. 比较退火处理以及未退火处理的铜基板与钎料界面IMC层生长速率常数,发现铜基板退火处理能减缓IMC层生长,主要归因于对铜基板进行退火处理能够有效的消除铜基板的内应力与组织缺陷,从而减缓Cu原子的扩散,起到减缓IMC生长的作用.     

Electromigration in solder joints and solder lines

Electromigration may affect the reliability of flip-chip solder joints. Eutectic solder is a two-phase alloy, so its electromigration behavior is different from that in aluminum or copper interconnects. In addition, a flipchip solder joint has a built-in currentcrowding configuration to enhance electromigration failure. To better understand electromigration in SnPb and lead-free solder alloys, the authors prepared solder lines in v-grooves etched on Si (001). This article discusses the results of those tests and compares the electromigration failure modes of eutectic SnPb and SnAgCu flip-chip solder joints along with the mean-timeto-failure.     

RE对Sn2.5Ag0.7Cu/Cu焊点性能的影响

利用X射线衍射分析仪(XRD)和JSM-5610LV扫描电镜(SEM)研究RE含量对Sn2.5Ag0.7Cu/Cu焊点界面区显微组织、剪切强度和蠕变断裂寿命的影响。结果表明:Sn2.5Ag0.7CuxRE焊点界面区金属间化合物由靠近钎料侧Cu6Sn5和靠近Cu基板侧Cu3Sn构成;添加微量RE可细化Sn2.5Ag0.7Cu焊点内钎料合金的显微组织和改善钎焊接头界面区金属间化合物的几何尺寸及形态;当RE添加量为0.1%时,焊点的剪切强度最高,蠕变断裂寿命最长。     

Ni对Sn96.5Ag3.5/Cu之间扩散行为的阻挡作用

研究了电镀Ｎｉ层和化学镀Ｎｉ－Ｐ合金层对Ｓｎ－Ａｇ／Ｃｕ焊点扩散行为的影响,电子探针分析表明,化学镀Ｎｉ－Ｐ合金层能很好地阻止Ｓｎ－Ａｇ／Ｃｕ焊点在焊接过程中的ＣｕＳｎ互扩散和相互反应;而电镀Ｎｉ层则不能阻止Ｓｎ－Ａｇ／Ｃｕ焊点过程中的Ｃｕ,Ｓｎ互搁工用和相互反应,界面反应产物以Ｃｕ６Ｓｎ５为主。应用化学镀Ｎｉ－Ｐ合金作为Ｓｎ－Ａｇ／Ｃｕ之间的扩散阻挡层可大大减少Ｓｎ／Ｃｕ金属间化合物的生成,有得     

SnCu钎料镀层与Cu/Ni镀层钎焊接头的界面反应

观察了不同焊接工艺条件下钎焊接头界面的微观结构，并对钎焊过程中的界面反应进行分析。探讨了钎缝界面处IMC的生长机制，通过对不同钎焊温度和保温时间下的IMC生长规律的分析建立铜锡化合物厚度与温度和时间的关系方程。结果表明：钎焊过程中SnCu钎料合金镀层与可焊性Cu层的界面处生成金属间化合物Cu6Sn5和Cu3Sn；化合物的生长厚度与焊接时间之间满足抛物线关系，表明化合物的生长为扩散反应控制过程，并随焊接时间的延长化合物的生长速率逐渐下降。     

6063铝合金／Ag／Ni／1Cr18Ni9Ti共晶反应钎焊研究

研究采用Ni-Ag复合镀层,在特定的工艺参数条件下,对6063铝合金与1Cr18Ni9Ti进行了共晶反应钎焊试验,初步分析探讨了工艺参数对钎缝微观组织结构反形态的影响和Ni层的阻隔作用.对钎缝的界面作扫描电镜和能谱分析发现,镀层与母材等各界面连接紧密,特别是钎缝与母材之间没有生成脆性Al-Fe金属间化合物.结果表明:在钎焊温度580℃,共晶反应钎焊6063铝合金1Cr18Ni9Ti,保温5 min,钎缝成形较好;面心立方结构Ni/Ag电刷镀层能有效地阻挡Al,Fe等原子扩散.