Ni添加量对铜基板和石墨烯铜基板的界面反应和IMC生长的影响（英文）

研究了钎焊与时效过程中,在Sn0.7Ag0.5Cu(SAC0705)钎料与Cu基板和石墨烯Cu基板界面处金属间化合物(IMC)的形成与演变。采用加热平台制备焊接试样并在120℃时效600h。结果表明,界面金属间化合物在时效过程中增厚。SAC0705/Cu和SAC0705/G-Cu 2种焊接界面金属间化合物均为Cu6Sn5。当钎料中添加Ni元素后,Cu6Sn5化合物转变为(Cu, Ni)6Sn5。随着钎料中Ni元素含量的增大,2种基板上的界面金属间化合物厚度先增加后减小。此外,随着Ni含量增大,化合物生长速率降低。石墨烯Cu基板表面的石墨烯层起到扩散阻挡层效果,因此,石墨烯Cu板上的化合物厚度小于常规Cu基板,同时其界面化合物生长速率较低。     

La对Sn-Ag-Cu无铅钎料与铜钎焊接头金属间化合物的影响

研究微量稀土La在钎焊和时效过程中对Sn-3.0Ag-0.5Cu无铅钎料与铜基板的钎焊界面及钎料内部金属间化合物(IMC)的形成与生长行为的影响.结果表明:钎焊后钎焊界面形成连续的扇形Cu6Sn5化合物层,其厚度随La含量的增加而减小;在150℃时效100h后,连续的Cu3Sn化合物层在Cu6Sn5化合物层和铜基板之间析出,且Cu6Sn5层里嵌有Ag3Sn颗粒;界面金属间化合物总厚度随时效时间的延长而增厚,且在相同时效条件下随La含量的增加而减小;时效过程中金属间化合物生长动力学的时间系数(n)随着La含量的增加逐渐增大;钎焊后钎料内部Ag仍以共晶形式存在,时效后Ag3Sn颗粒沿钎料内部的共晶组织网络析出.     

Sn-5Sb-CuNiAg/Ni微焊点抗时效性能的研究

以适合功率器件互联的Sn-5Sb基钎料与Cu镀Ni基板连接为研究对象,研究Sn-5Sb钎料中添加Cu,Ni,Ag元素对接头的抗时效性能的影响。将三种Sn-5Sb-CuNiAg钎料、Sn-5Sb,SAC305分别与Cu镀Ni基板连接,借助SEM和EDX,进行微观组织对比分析,研究体钎料在时效过程中的基体组织及化合物的演变规律,界面化合物的生长随时效时间的演变规律。结果表明,Sn-5Sb-CuNiAg和SAC305体钎料中主要为块状化合物(Cu,Ni)_6Sn_5和颗粒状银锡化合物,Sn-5Sb体钎料主要为块状化合物(Cu,Ni)_6Sn_5。随时效时间延长,体钎料中的化合物均变得粗大。界面化合物层明显变厚,化合物形貌从不规则的锯齿状逐渐向平缓均匀的层状转变。Sn-5Sb-CuNiAg焊点的界面化合物层厚度比Sn-5Sb、SAC305焊点的界面化合物层厚度相对要薄,Sn-5Sb-CuNiAg焊点具有更好的抗热时效性能。添加0. 5%质量分数的Cu和0. 1%质量分数的Ni元素对界面IMC的生长速率有抑制作用。     

Ni和Bi元素对SnAgCu钎焊界面金属化合物生长速率的影响

通过加速温度时效方法研究Ni和Bi元素对低银(含银量小于1%,质量分数)Sn-Ag-Cu(LASAC)钎料界面IMC生长速率的影响。通过与高银钎料SAC305和低银钎料LASAC对比,分析添加Ni和Bi元素后LASAC钎料在高温时效过程中热疲劳抗性的变化情况。结果表明:LASAC/Cu、LASAC-Bi/Cu和SAC305/Cu界面IMC时效后均形成较厚的Cu3Sn层,LASAC-Ni/Cu界面经IMC时效后则形成较薄的(Cu,Ni)3Sn;高银钎料SAC305在180℃时效下IMC生长速率为2.17×10-5μm2/s,与之相比,低Ag钎料LASAC IMC在时效过程中生长速率较高,为3.8×10-5μm2/s;Ni和Bi元素的添加均可降低钎料LASAC/Cu界面IMC的生长速率,其中Bi的改善效果最显著,LASAC-Bi钎料的IMC生长速率为1.92×10-5μm2/s,低于SAC305钎料的IMC生长速率。     

界面耦合作用对Cu(Ni)/Sn-Ag-Cu/Cu(Ni)BGA焊点界面IMC形成与演化的影响

研究了焊盘材料界面耦合作用对Cu(Ni)/Sn-3.0Ag-0.5Cu/Cu(Ni)BGA(Ball Grid Array)结构焊点焊后态和125℃等温时效过程中界面金属间化合物(IMC)的成分、形貌和生长动力学的影响.结果表明.凸点下金属层(UBM)Ni界面IMC的成分与钎料中Cu含量有关,钎料中Cu含量较高时界面IMC为(Cu.Ni)6Sn5.而Cu含量较低时,则生成(Cu,Ni)_3Sn_4;Cu-Ni耦合易导致Cu/Sn-3.0Ag 0.5Cu/Ni焊点中钎料/Ni界面IMC异常生长并产生剥离而进入钎料.125℃等温时效过程中.Sn-3.0Ag-0.5Cu/Cu界面IMC的生长速率常数随钎料中Cu含量增加而提高.Cu Cu耦合降低一次回流侧IMC生长速率常数;Cu Ni耦合和Ni-Ni耦合均导致焊点一次回流Ni侧界面IMC的生长速率常数增大,但Ni对界面IMC生长动力学的影响大于Cu;Ni有利于抑制Cu界面Cu_3Sn生长.降低界面IMC生长速率,但Cu-Ni耦合对Cu界面Cu_3Sn中Kirkendall空洞率无明显影响     

倒装LED回流焊接头组织的抗高温时效性能

以SAC305锡膏为钎料,通过回流焊实现了倒装LED与Cu/Ag、Cu/Ni/Au基板的互连.研究了两种接头界面微观组织在高温时效条件下的演变行为.结果表明,接头两侧界面组织间存在相互影响. Cu/Ni/Au基板中的Au在回流焊过程中溶解至体钎料内,对芯片侧Au-Sn金属间化合物的生长起到抑制效果.芯片侧Au-Sn金属间化合物的快速生长降低了体钎料中Sn的相对浓度,从而使体钎料中有利于基板侧IMC生长组元的相对浓度得到提升,促进基板侧IMC生长.相比较而言,在Cu/Ag基板上的回流焊试样抗高温时效性能较差.     

铜含量对Sn-Cu钎料与Cu、Ni基板钎焊界面IMC的影响

研究了不同铜含量的Sn-xCu钎料(x=0,0.1%,0.3%,0.7%,0.9%,1.5%)与Cu板和Ni板在260、280和290℃钎焊后界面金属间化合物(IMC)的成分和形貌。研究结果表明:钎料与Cu板钎焊时,钎焊温度越高,界面处形成的Cu6Sn5IMC厚度越大,而在同一钎焊温度下,随着钎料中铜含量的增加,IMC的厚度先减少后增加;与Ni板钎焊时,界面IMC的厚度随着铜含量的增加而增加,同时界面化合物的成分和形貌均发生了显著变化;当Cu含量小于0.3%(质量分数)时,界面处形成了连续的(CuxNi1-x)3Sn4层;而当Cu含量为0.7%时,界面处同时存在着短棒状(CuxNi1-x)3Sn4和大块状(CuxNi1-x)6Sn5IMC;当铜含量继续增大时(0.9%~1.5%),(CuxNi1-x)3Sn4IMC消失,只发现了棒状(CuxNi1-x)6Sn5IMC。讨论了钎料中Cu含量对与Cu、Ni基板钎焊接头界面化合物生长的影响,并进一步讨论了(CuxNi1-x)6Sn5IMC的形成和长大机理。     

高温时效过程中SnAgCu钎焊接头显微组织的演化规律

研究了215℃时效过程中Sn3.8Ag0.7Cu无铅钎料焊点内部及与Cu基板界面处显微组织的演化规律.结果表明:试样在时效过程中的放置方式对显微组织的变化会产生重要影响.当钎料焊点处于Cu基板的上方时,215℃时效后显微组织的变化与以往170℃时效后显微组织的变化相似,即界面处金属间化合物层的厚度会随着时效时间的延长而逐渐增加.然而,当钎料焊点处于Cu基板的下方时,215℃时效后钎料焊点内部及界面处的显微组织发生了显著的变化,伴随着Cu基板的溶解在钎料焊点表面形成了大量的体积较大的金属间化合物Cu6Sn5.     

倒装芯片组装中微米级互连焊点的界面金属间化合物生长及动力学

利用焊点间距为100 μm,高度约为45 μm,成分为Sn-3.0Ag-0.5Cu (wt％) (SAC305)的倒装硅芯片与BT树脂基板组装互连,分别在150、125和100℃条件下时效至650 h.研究时效过程中界面主要金属间化合物的生长,结合经验功率定律及阿伦斯公式计算基板侧Cu焊盘界面IMC生长的动力学参数,对IMC的生长动力学探讨.结果表明,在互连回流后,双侧焊盘界面主要IMC为(Cu,Ni)6Sn5.在时效前100 h,(Cu,Ni)6Sn5生长速率较快;而在随后的时效过程中,随时效时间的增加生长速率逐渐降低.界面主要金属间化合物(Cu,Ni)6Sn5生长动力学研究结果可知:150、125以及100℃条件下时间参数分别为2.61、2.35和2.18,界面(Cu,Ni)6Sn5的生长激活能为67.89 kJ/mol.     

Bi对Sn-0.3Ag-0.7Cu-xBi/Ni焊点IMC的影响

无铅钎料和基板间金属间化合物(1MC)的生长对元器件的可靠性有重要影响.使用Sn-0.3Ag-0.7Cu-xBi无铅钎料与Ni盘进行焊接,并对焊点进行了180℃时效试验,时效时间分别为O、24、96、216和384h.采用金相显微镜、扫描电镜和能谱仪观察分析了钎料与Ni界面IMC的生长及形貌变化,并对其焊点IMC层Ni的分布进行了分析,同时对其界面生长速率进行了拟合.结果表明:Sn-0.3Ag-0.7Cu焊料与Ni焊盘之间的IMC是棒状的(CuxNi1-x)6Sn5,Bi的加入并没有起到很好的抑制作用,而是随着Bi含量的增加IMC先增加后减少.Sn-O.3Ag-0.7Cu/Ni焊点IMC中Ni的平均含量(wN)分为15%、5%两区域.由近Ni向钎料基体方向呈下降趋势.但是Sn-O.3Ag-0.7Cu-3.0Bi/Ni焊点IMC中Ni的平均含量在7%左右.时效后IMC层的厚度会随着老化时间的延长而增加,但是Sn-0.3Ag-0.7Cu-xBi/Ni焊点由于Bi的析出IMC增长得缓慢;Sn-0.3Ag-0.7Cu/Ni焊点(CuxNi1-x)6Sn5中15%Ni的含量区域逐渐过渡到5%区域,但是Sn-0.3Ag-0.7Cu-xBi/Ni焊点IMC中Ni的平均含量维持9%较时效前有所增加.通过生长速率计算,Sn-O.3Ag-0.7Cu-xBi/Ni焊点IMC的生长速率随着Bi含量的增加而减少.     

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.     

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.     

SAC0307-xNi/Ni焊点的IMC及镍镀层的消耗

利用扫描电镜(SEM)对焊点SAC0307/Ni(Sn-O.3Ag-0.7Cu/Ni)和SAC0307-0.05Ni/Nj(Sn-O.3Ag-0.7Cu-0.05 Ni/Ni)经过180℃老化后的界面金属问化合物(IMC)的微观结构及镍镀层的消耗进行了研究.结果表明,回流焊后,SAC0307/Ni和SAC0307-O.05Ni/Ni焊点的IMC层均为(Cu_(1-x)Ni_x)_6Sn_5,且随着老化时间的延长,IMC层的厚度均逐渐增加,化合物类型没有变化,但IMC的化学组成有所改变.SAC0307-0.05Ni/Ni焊点中IMC层形貌为蠕虫状,厚度比不加镍时有所降低.回流焊后两种钎料焊盘的镍层消耗几乎相同,但老化384h后SAC0307/Ni的焊盘镍层的剩余厚度明显比SAC0307-0.05Ni/Ni的小.因此,钎料中添加适量的镍可以有效地降低焊盘镍层在时效过程中的消耗速率,即显著提高镍焊盘的抗老化能力.

Abstract：

The micrestmcture of interfacial IMC and the consumption of Ni layer for SAC0307/Ni ( Sn-0.3Ag-0.7Cu/Ni ) soldered joint and SAOY307-0.05Ni/Ni (Sn-O. 3Ag-0.7Cu-0.05Ni/Ni) soldered joint after aging at 180℃ were studied by scanning electron microscope( SEM ). The results indicated that the IMC layer of SAC0307/Ni and SAC0307-0.05Ni/Ni are both (Cu_(1-x),Ni_x)_6Sn_5 after reflow soldering. With the increasing of aging time, the thickness of IMC layer increases gradually, the type of IMC is not changed, but the chemical composition changes. The morphology of IMC is stormshaped and the thickness of IMC is much thinner when SAC0307 solder added 0. 05 % Ni is used. The consumption of Ni layer is nearly the same using both solders "after the first time reflow soldering, but the residual thickness of the Ni layer in SACO307/Ni solder is thinner than that in SAC0307-0.05Ni/Ni after aging for 384 h. So solders with a little Ni element can decrease the consumption rate of Ni layer effectively during aging, that is, the aging-resistant abihty of Ni pad is improved obviously.     

Influence of rare earth Ce addition on the microstructure,properties and soldering reaction of pure Sn

The influence of trace rare earth (RE) Ce addition on the microstructure, melting point and wettability of pure Sn as well as on the soldering reactions in Sn-xCe/Cu(Ni) solder joints was investigated. In bulk Sn-xCe solders, large β-Sn grains were observed with the Ce addition less than 0.2 wt%; while the β-Sn grain size decreased markedly when the Ce addition was 0.2 wt%, resulting in a refined microstructure. The addition of trace RE Ce had little effect on the melting temperature of the solders. Smaller wetting angles of Sn-xCe solders on both Cu and Ni substrates were measured when the samples were reflowed at a higher temperature. The Sn-0.2Ce solder owned the best wettability on Cu substrate. Scallop-like Cu₆Sn₅ intermetallic compound (IMC) grains formed at the Sn-xCe/Cu interfaces, while a continuous Ni₃Sn₄ IMC layer formed at each Sn-xCe/Ni interface. With the increase of Ce addition, the interfacial IMC grain size and the interfacial IMC layer thickness on both Cu and Ni substrates decreased gradually. The activity of Sn was lowered with the Ce addition, which depressed the growth of the interfacial IMC. In the current study, the Ce addition of 0.2 wt% exhibits the optimized performance.     

Intermetallic compound growth suppression at high temperature in SAC solders with Zn addition on Cu and Ni-P substrates

The effect of adding 0.5-1.5 wt.% Zn to Sn-3.8Ag-0.7Cu (SAC) solder alloy during reflow and solid state ageing has been investigated. In particular, the role of the Zn addition in suppressing interfacial Intermetallic Compound (IMC) growth on Cu and Ni-P substrates has been determined. Solder-substrate couples were aged at 150 °C and 185 °C for 1000 h. In the case of 0.5-1.0 wt.% Zn on Cu substrate, Cu₃Sn IMC was significantly suppressed and the morphology of Cu₆Sn₅ grains was changed, leading to suppressed Cu₆Sn₅ growth. In the SAC-1.5Zn/Cu substrate system a Cu₅Zn₈ IMC layer nucleated at the interface followed by massive spalling of the layer into the solder, forming a barrier layer limiting Cu₆Sn₅ growth. On Ni-P substrates the (Cu,Ni)₆Sn₅ IMC growth rate was suppressed, the lowest growth rate being found in the SAC-1.5Zn/Ni-P system. In all cases the added Zn segregated to the interfacial IMCs so that Cu₆Sn₅ became (Cu,Zn)₆Sn₅ and (Cu,Ni)₆Sn₅ became (Ni,Cu,Zn)₆Sn₅. The effect of Zn concentration on undercooling, wetting angles and IMC composition changes during ageing are also tabulated, and a method of incorporating Zn into the solder during reflow without compromising solder paste reflow described.     

电迁移对Ni/Sn3.0Ag0.5Cu/Cu焊点界面反应的影响

研究了温度为150℃,电流密度为5.0×10³A/cm²的条件下电迁移对Ni/Sn3.0Ag0.5Cu/Cu焊点界面反应的影响.回流焊后在Sn3.0Ag0.5Cu/Ni和Sn3.0Ag0.5Cu/Cu的界面上均形成了（Cu,Ni）₆Sn₅型化合物.时效过程中界面化合物随时效时间增加而增厚,时效800 h后两端的化合物并没有发生转变,仍为（Cu,Ni）₆Sn₅型.电流方向对Cu基板的消耗起着决定作用.当电子从基板端流向芯片端时,电流导致基板端Cu焊盘发生局部快速溶解,并导致裂纹在Sn3.0Ag0.5Cu/（Cu,Ni）₆Sn₅界面产生,溶解到钎料中的Cu原子在钎料中沿着电子运动的方向向阳极扩散,并与钎料中的Sn原子发生反应生成大量的Cu₆Sn₅化合物颗粒.当电子从芯片端流向基板端时,芯片端Ni UBM层没有发生明显的溶解,在靠近阳极界面处的钎料中有少量的Cu₆Sn₅化合物颗粒生成,电迁移800 h后焊点仍保持完好.电迁移过程中无论电子的运动方向如何,均促进了阳极界面处（Cu,Ni）₆Sn₅的生长,阳极界面IMC厚度明显大于阴极界面IMC的厚度.与Ni相比,当Cu作为阴极时焊点更容易在电迁移作用下失效.     

Suppressing effect of 0.5 wt.% nano-TiO2 addition into Sn-3.5Ag-0.5Cu solder alloy on the intermetallic growth with Cu substrate during isothermal aging

This study investigated the effects of adding 0.5 wt.% nano-TiO₂ particles into Sn3.5Ag0.5Cu (SAC) lead-free solder alloys on the growth of intermetallic compounds (IMC) with Cu substrates during solid-state isothermal aging at temperatures of 100, 125, 150, and 175 °C for up to 7 days. The results indicate that the morphology of the Cu₆Sn₅ phase transformed from scallop-type to layer-type in both SAC solder/Cu joints and Sn3.5Ag0.5Cu-0.5 wt.% TiO₂ (SAC) composite solder/Cu joints. In the SAC solder/Cu joints, a few coarse Ag₃Sn particles were embedded in the Cu₆Sn₅ surface and grew with prolonged aging time. However, in the SAC composite solder/Cu aging, a great number of nano-Ag₃Sn particles were absorbed in the Cu₆Sn₅ surface. The morphology of adsorption of nano-Ag₃Sn particles changed dramatically from adsorption-type to moss-type, and the size of the particles increased.The apparent activation energies for the growth of overall IMC layers were calculated as 42.48 kJ/mol for SAC solder and 60.31 kJ/mol for SAC composite solder. The reduced diffusion coefficient was confirmed for the SAC composite solder/Cu joints.     

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