Sn-Ag-Cu系无铅焊锡的力学性能和实用性能

研究添加稀土Ce对Sn-Ag-Cu合金的力学性能和实用性能的影响,利用光学显微镜、SEM、EDX对合金的组织、形貌、成分进行分析。结果表明,在Sn-Ag-Cu系无铅焊锡中添加稀土Ce可以细化合金组织,使合金成分分布更加均匀;稀土Ce的添加可以明显提高合金的延伸率;添加Ce后延伸率提高了6.1%,从而使力学性能大大提高;适量稀土的加入使焊料与基体结合更加紧密,外观平整,对合金的实用性能有很大提高。     

铜铟铋硫对Sn-Ag基无铅焊料性能的影响

研究了Cu、In、Bi、S元素对Sn-Ag基无铅焊料熔点和铺展性的影响。结果表明:Sn-Ag-Cu三元合金成分为95.5%Sn3.5%Ag1%Cu时具有较低熔点(215℃)和好的铺展性;加入适量的In可降低Sn-Ag合金的熔点和改善铺展性能;随w(Bi)的增加Sn-Ag-Bi三元合金的熔点降低、铺展性变好;Sn-Ag合金的熔点随w(S)的增加而升高,加入少量S能改善Sn-Ag合金的铺展性。     

无铅焊锡制造常见问题

面对无铅焊锡时代,ApolloSeiko自动焊锡设备能为产业界提供什么创新技术？在已出土的古希腊文物中可以得知。焊锡技术历史久远。更令人吃惊的是。那时尚未成熟的;台金技术就已经把锡（Sn）与铅（Pb）的合金成份定在接近63：37的最佳比例。这个比例的锡铅合金熔点最低、     

无铅焊锡的再流焊工艺及设备

介绍了日本等国家用无铅焊锡的发展趋势及无铅焊锡的再流焊工艺与设备。     

环氧基材PCB对无铅焊锡装配适应性的研究

讨论了环氧基材PCB对无铅焊锡装配的适应性、铜竭顶的可靠性，证明双氰胺固化的环氧基材不能适直无铅焊锡装配：酚醛树脂固化的环氧基材有解决此问题可能性，但都是PCB制造商们的技术决窍。     

低银Sn-Ag-Cu无铅钎料的性能研究

使用银含量较低的Sn-Ag-Cu无铅钎料是降低焊料成本最直接有效的手段之一,但银含量降低后对钎料性能的影响尚缺乏系统报导。通过向Sn-Cu二元体系中加入不同比例的纯银,制备了一系列低银合金。研究了银含量对钎料的熔点、可焊性及溶铜性能的影响。通过拉伸试验研究了合金的强度及杨氏模量。综合考虑上述各项性能指标,Sn-0.5Ag-0.7Cu是具有最佳性价比的合金成分。     

Sn-Cu、Sn-Ag-Cu系无铅钎料的钎焊特性研究

制备了Sn-0.7Cu、Sn-3.5Ag-0.6Cu钎料,用润湿平衡法测量了钎料对铜的润湿曲线,研究了温度、钎剂活性、钎焊时间对润湿行为的影响,并与Sn-37Pb钎料进行了比较。结果表明:升高温度能显著改善无铅钎料对铜的钎焊性。当温度<270℃时,Sn-0.7Cu的钎焊性明显低于Sn-3.5Ag-0.6Cu钎料;而当温度≥270℃时,两种钎料对铜都会显示较好的润湿性,而Sn-0.7Cu略优于Sn-3.5Ag-0.6Cu钎料。提高钎剂活性能显著增强钎料对铜的润湿性,其卤素离子的最佳质量分数均为0.4%左右。随着浸渍时间的延长,熔融钎料与铜的界面间产生失润现象。无铅钎料的熔点和表面张力较高,是钎焊性较差的根本原因。     

自动光学检验设备(AOI)对无铅焊锡的检测

在倡导废除使用环境污染物质铅的进程中,各生产厂家都逐步地开始采用去除了焊锡中铅成分的无铅焊锡。对焊锡无铅化引起外观的变化和特征进行了论述,并说明了无铅化与焊锡外观检测的关系,以及欧姆龙公司在无铅化应用上新开发的功能。     

Sn-Ag-Cu无铅焊料的可靠性研究

欧盟对电子产品的RoHS法令的实施加快了电子封装钎焊无铅化的步伐。Sn-Ag-Cu焊料以其优良的机械性能和可焊性,逐渐得到了国际社会的认可。文章对无铅焊料的发展过程,Sn-Ag-Cu合金的性能进行了综述,重点介绍了Sn-Ag-Cu焊点的可靠性,包括试验法和有限元法。最后对Sn-Ag-Cu焊料的应用前景进行了展望。     

Ce对SnAgCu系无铅焊锡力学性能的影响

通过向Sn-3Ag-2.8Cu钎料合金中添加微量稀土Ce,利用扫描电子显微镜(SEM)研究了不同稀土含量对Sn-3Ag-2.8Cu合金的力学性能的影响,同时对显微组织进行了分析.实验结果表明,微量的Ce稀土可以显著提高Sn-3Ag-2.8Cu钎料的延伸率、延长其焊接接头在室温下的蠕变断裂寿命,尤其是当稀土的质量分数为0.1%时,其蠕变断裂寿命可以达到Sn-3Ag-2.8Cu钎料的9倍以上,当稀土的质量分数超过0.1%时,接头的蠕变断裂寿命呈下降趋势.综合考虑,最佳的稀土质量分数为0.05%～0.10%.     

Study of Solidification Cracks in Sn-Ag-Cu Lead-Free Solder Joints

In the present work, solidification cracks in Sn-Ag-Cu solder joints were investigated. Experimental results indicate that solidification cracks existed in significant numbers in the miniature Sn-Ag-Cu solder joints. In order to create solidification cracks in the miniature solder joints during solidification and evaluate the susceptibility of Sn-Ag-Cu alloys to solidification cracking, a copper self-restraint specimen was designed, which can simulate the process of solidification crack formation. The solidification crack susceptibility of the Sn-Ag-Cu solder alloy was evaluated using the total crack length of the solder joint. In addition, the effect of trace amounts of elemental additions on solidification cracking of Sn-Ag-Cu solder joints was studied. It was found that adding trace amounts of Ni or Ce could depress the solidification cracks in Sn-3.0Ag-0.5Cu solder joints. However, P additions aggravated the formation of solidification cracks.     

锡铅稀土钎料合金高温蠕变性能试验研究

文中对比分析了Ｓｎ６０Ｐｂ４０和Ｓｎ－Ｐｂ－０．０５Ｒｅ两种钎料合金在多轴应力状态下的蠕变断裂规律,初步探讨了主控两种钎料复合金为断裂的力学因素,并从金属学角度初步探讨了两种钎料合金的蠕变断裂方式,着重分析了混合稀土对锡铅秆料合金蠕变性能的影响。     

Ce对Sn-Ag-Cu系焊料合金的组织与性能影响

通过添加稀土Ce研究了Sn-3.0Ag-2.8Cu系焊料合金的显微组织和性能。用光学显微镜、SEM、EDX对其显微组织进行分析,并且对其导电性,润湿性,硬度等重要性能进行测试。结果表明,添加稀土w(Ce)为1%焊料合金的导电性明显提高;而润湿角明显减小,润湿性增强;同时焊料合金的硬度也有所增加。     

Effect of SiC Nanoparticle Additions on Microstructure and Microhardness of Sn-Ag-Cu Solder Alloy

In this work, lead-free composite solders were produced by mechanically mixing nominal 20 nm moissanite SiC particles with Sn-3.8Ag-0.7Cu solder paste. The effects of the amount of SiC addition on the melting behavior, microstructure, and microhardness of as-solidified composite solders were systematically investigated. In comparison with solder without the addition of SiC nanoparticles, the subgrain of β-Sn, the intermetallic compounds (IMCs) average grain size and distance decreased significantly in the composite solder matrix. This was possibly ascribed to the strong adsorption effect and high surface free energy of the SiC nanoparticles. Our results showed that 0.05 wt.% addition of SiC nanoparticles could improve the microhardness by 44% compared with the noncomposite and that the average grain size and distance changed from 0.5 μm to 0.2 μm and from 0.6 μm to 0.32 μm, respectively. The refined IMCs, acting as a strengthening phase in the solder matrix, enhanced the microhardness of the composite solders, in good agreement with the prediction of the classic theory of dispersion strengthening.     

微电子封装中Sn—Aq—Cu焊点剪切强度研究

提出了一种对微电子封装器件中焊点剪切强度进行测试的方法，可有效降低测试误差。利用该方法，对Sn—Ag—Cu无铅焊料分别在Cu基板和Ni-P基板上形成的焊点，经不同的热时效后的剪切强度进行了测量，并对断裂面的微观结构进行了研究。结果表明，新的剪切测试方法误差小，易于实施，焊点剪切强度、断裂面位置与焊料在不同基板界面上金属间化合物的形貌、成分有关。     

无铅钎料发展现状

无铅钎料是绿色电子产品的一个重要组成部分。本文综述了近年来国际上无铅钎料的发展动态，并为国内企业如何适应这一趋势提出了建议。     

浅谈Sn-Ag-Cu无铅焊料的可靠性

随着电子组装技术的发展,电子产品在制造过程中使用的焊料也随之更新换代,由原来的使用锡铅焊料改为使用无铅焊料,特别是Sn-Ag-Cu焊料,以满足WEEE和RoHS指令以及其他方面的要求。然而,使用无铅焊料却带来了一系列的问题,这些问题自然影响到产品的可靠性和使用寿命,因此,成为业界最关注的热点问题。文章主要讨论了Sn-Ag-Cu焊料的可靠性等问题。     

The Influence of an Imposed Current on the Creep of Sn-Ag-Cu Solder

The work reported here included preliminary tests on the influence of an imposed current on the creep rate of the Pb-free solder Sn-Ag-Cu 305 (Sn-3Ag-0.5Cu in wt.%). The samples employed were double-shear specimens that contained paired solder joints, 400 μm × 400 μm in cross-section, 200 μm in thickness on Cu. Three tests were done. In the first, samples were tested under stress at room temperature with imposed current densities that ranged from 1 × 10³ A/cm² up to 6.5 × 10³ A/cm². As expected, because of Joule heating, the results show a sharp increase in creep rate with the imposed current density. A second set of tests was done to determine whether Joule heating fixed the creep rate. The steady-state temperature of the solder joints was measured under current, and samples were creep-tested at that temperature. Surprisingly, the creep rate under current was significantly below that measured in isothermal tests at the same temperature. The third set of tests studied the influence of microstructure. Samples were prepared with three starting microstructures: as cast, thermally aged by long-term isothermal exposure, and current aged by long-term exposure to a fixed current density. The three microstructures were then tested with and without current at two ambient temperatures. The different microstructures had very different creep rates in the absence of current but, surprisingly, imposing a current (5.5 × 10³ A/cm²) increased the creep rate by very nearly the same factor (~7×) in every case. Neither of these results is well understood at this time.     

Effect of Homogenization on the Indentation Creep of Cast Lead-Free Sn-5%Sb Solder Alloy

Creep behavior of cast lead-free Sn-5%Sb solder in unhomogenized and homogenized conditions was investigated by long time Vickers indentation testing under a constant load of 15 N and at temperatures in the range 321–405 K. Based on the steady-state power law creep relationship, the stress exponents were found for both conditions of the material. The creep behavior in the unhomogenized condition can be divided into two stress regimes, with a change from the low-stress regime to the high-stress regime occurring around 11.7 × 10⁻⁴ < (H _V /E) < 18 × 10⁻⁴. The low stress regime activation energy of 54.2 kJ mol⁻¹, which is close to 61.2 kJ mol⁻¹ for dislocation pipe diffusion in the Sn, and stress exponents in the range 5.0–3.5 suggest that the operative creep mechanism is dislocation viscous glide. This behavior is in contrast to the high stress regime in which the average values of n = 11.5 and Q = 112.1 kJ mol⁻¹ imply that dislocation creep is the dominant deformation mechanism. Homogenization of the cast material resulted in a rather coarse recrystallized microstructure with stress exponents in the range 12.5–5.7 and activation energy of 64.0 kJ mol⁻¹ over the whole ranges of temperature and stress studied, which are indicative of a dislocation creep mechanism.     

BGA无铅焊点零空洞缺陷控制研究

在无铅BGA封装工艺过程中,通过不同组分的BGA焊球合金与焊膏合金组合焊接、焊膏助焊剂活性剂不同配比及其不同再流焊接条件等实验,对焊料合金和助焊剂配比、再流焊接峰值温度、再流保温时间等参数变化,以降低BGA焊点空洞缺陷进行了研究。结果表明选用相同或相似的BGA焊球和焊膏合金组合焊接、选用活性强的焊膏、选择焊接保温时间较长均有助于降低BGA焊点空洞缺陷产生的几率和空洞面积,BGA焊点最佳再流焊接峰值温度为240℃,当峰值温度设置为250℃时,BGA焊点产生空洞缺陷几率会比240℃高出25%～30%。