热处理对96.5Sn3.5Ag焊点中Cu—Sn合金层的影响

在焊点与铜基之间形成的Ｃｕ－Ｓｎ合金成分对表面安装器件的疲劳寿命起着关键性的作用。本文着重研究了９３．５Ｓｎ３．５Ａｇ焊料与Ｃｕ界面间形成的合金层,通过电子扫描显微镜,Ｘ衍射及能谱Ｘ射线等分析发现。     

添加Sn-Ag对Sn-Bi焊接特性的改善

研究了ｘ４２Ｓｎ５８Ｂｉ－（１－ｘ）９６．５Ｓｎ３．５Ａｇ系中不同组成的焊料。研究表明在４２Ｓｎ５８Ｂｉ（简称ＳＢ）焊料中添加适量的９６．５Ｓｎ３．５Ａｇ（简称ＳＡ）,能改善焊点的焊接温度。通过对焊点切向拉力的测试分析,发现适量的ＳＡ能提高焊点的强度,并在高低温分别为＋１２５℃和－４０℃下进行热冲击１０００次后,其强度减小程度远小于纯的ＳＢ焊料焊点。表明其焊点的机械及疲劳性能都得到了提高。通过透射Ｘ射线及扫描电子显微镜（ＳＥＭ）分析,发现Ｓｎ－Ａｇ的添加可以减少焊点中孔洞的出现。     

添加Sn—Ag对Sn—Bi焊接特性的改善

研究了ｘ４２Ｓｎ５８Ｂｉ－（１－ｘ）９６。．５Ｓｎ３．５Ａｇ系中不同组成的焊料,表明在４２Ｓｎ５８Ｂｉ（简称ＳＢ）焊料中添加适量的９６．５Ｓｎ３．５Ａｇ,能改善焊妆温度。通过对焊向拉力的测试分析,发现一的ＳＡ能提高焊点的强度并在高低温分别为＋１２５℃和－４０℃下进行热冲击１０００次后,其强度减不程度远小于纯的ＳＢ焊料焊点。其焊点的机械及疲劳性能得到了提高。通过透射Ｘ射线及扫描电子显微镜（ＳＥＭ）分     

62Sn－36Pb－2Ag焊点的可靠性及热疲劳位错亚结构的演化分析

采用热疲劳试验分析了表面封装焊点的可靠性。讨论了不同的元器件及基片镀层工艺对焊点可靠性的影响，初步探讨了热疲劳过程中位错亚结构的变化及焊点的失效机理。结果表明：金属间化合物对焊点失效有重要影响．镀Ａｕ焊点热疲劳裂纹萌生于ＡｕＳｎ４金属间化合物并在其中扩展，镀Ｎｉ／Ａｕ焊点热疲劳过程中位错在ＡｕＳｎ４粒子处塞积，引起ＡｕＳｎ４／β－Ｓｎ界面应力集中，导致热疲劳裂纹沿ＡｕＳｎ４／β－Ｓｎ界面萌生，萌生后的裂纹在β－Ｓｎ相中扩展，ＴＥＭ观察也证明β－Ｓｎ相中位错密度较高。     

42Sn58Bi—96.5Sn3.5Ag系焊点疲劳性能的研究

本文研究了热处理时间对不同组分的４２Ｓｎ５８Ｂｉ－９６．５Ｓｎ３．５Ａｇ焊料疲劳性能的影响,研究发现适当的热处理时间能提高焊点的机械强度,延长焊点的疲劳寿命。     

创新推出8倍速DVD-ROM套件

创新公司的ＤＶＤ－ＲＯＭ套件又将升级,配备８倍速ＤＶＤ－ＲＯＭ的ＰＣ－ＤＶＤＥｎｃｏｒｅ８Ｘ即将上市。ＰＣ－ＤＶＤＥｎｃｏｒｅ８Ｘ套件包括一个８ＸＤＶＤ－ＲＯＭ和一块采用Ｄｘｒ３技术的ＭＰＥＧ２解压缩卡,能提供效果上佳的硬件ＭＰＥＧ２解压缩的影音播放效果。创新的ＤＸＲ３（ＤｙｎａｍｉｃＸｔｅｎｄｅｄＲｅｓｏｌｕｔｉｏｎ３）技术,除了能完成硬件ＭＰＥＧ２解压缩外,还可将ＤＶＤ影片普遍使用的ＡＣ－３５．１声道数码音效输出,再通过ＡＣ－３解码器由５．１声道音箱输出相当于影院的效果,该卡还配有Ｓ／ＰＤＩ…     

MmNi5-基储氢合金扫描电镜能谱仪定量分析

使用配备ＥＤＳ的ＳＥＭ,研究了ＭｍＮｉ５－基储氢合金的微观组织和微区成分。研究的合金中稀土元素含量低于化学比,晶界有Ｃｏ,Ｍｎ和Ａｌ富集相析出。分别使用ＲｅＢ６、ＲｅＰ５Ｏ和纯稀土金属作为分析稀土元素的标样进行定量分析。结果表明,全部采用纯金属标样（包括纯稀土金属标样）分析结果最好;采用ＲｅＢ６和ＲｅＰ５Ｏ１４作为分析稀土的标样时,分析误差较大。文章对误差较大的产生原因进行了讨论。     

1微米硅栅CMOSASIC制造中RIE的应用

本文主要介绍１ｕｍ双阱双层金属布线硅栅ＣＭＯＳ专用集成电路制造中采用先进的反应离子刻蚀技术，对多种材料如ＬＰＣＶＤ、Ｓｉ３Ｎ４、ＰＥＣＶＥＳｉ３Ｎ４、热ＳｉＯ２、ＰＥＶＥＤＳｉＯ２、ＰＳＧ、ＢＰＳＧ、多晶硅和Ａｌ－Ｓｉ（１．０％）－Ｃｕ（０．５％）合金等进行高选择比的，各向异性刻蚀的工艺条件及其结果。获得上述各种材料刻蚀后临界尺寸（ＣＤ）总损失＜０．０８ｕｍ的优良结果。此外还分析讨论了被选择的刻蚀     

激光熔敷NiCrSiB合金组织与物相研究

报道了对ＮｉＣｒＳｉＢ激光熔敷合金中共晶组织的研究和观察，将共晶中的第二相标定为Ｎｉ３１Ｓｉ１２。γ′（Ｎｉ３Ｓｉ）相与γ（Ｎｉ，Ｃｒ）相共存于枝晶中，共晶包围着枝晶形成合金的基体，其上弥散分布着硬质强化相ＣｒＢ，Ｎｉ３Ｂ和Ｍ２３（ＣＢ）６。研究方法包括ＳＥＭ（扫描电子显微镜），电子探针，ＸＲＤ（Ｘ射线衍射），ＥＤＡＸ（能谱分析）和波谱分析等     

InGaAs／GaAs应变层量子阱激光器深中心行为

应用深能级瞬态谱（ＤＬＴＳ）技术研究分子束外延（ＭＢＥ）和二次液相外延（ＬＰＥ）生长的ＩｎＧａＡｓ／ＧａＡｓ应变层量子季阱激光器深中心行为．在ＭＢＥ激光器的ｎ－ＡｌｘＧａ１－ｘＡｓ组分缓变层和限制层里，除众所周知的ＤＸ中心外，还观察到有较大俘获截面的深（空穴、电子）陷阱及其相互转化．这些陷阱可能分布在ｘ从０到０．４０和ｘ—０．４０的ｎ－ＡｌｘＧａ１－ｘＡｓ层里ｘ值不连续的界面附近．而在ＬＰＥ激光器的ｎ－ＡｌｘＧａ１－ｘＡｓ组分缓变层和限制层里，ＤＸ中心浓度明显减少，且深（空穴、电子）陷阱消失     

Effect of Cu stud microstructure and electroplating process onintermetallic compounds growth and reliability of flip-chip solder bump

In electroplating-based flip-chip technology, the Cu stud and solder deposition processes are two of the most important factors affecting the reliability of solder joints. The growth of Cu-Sn intermetallic compounds (IMC) also plays a critical role. In this paper, the effect of Cu stud surface roughness and microstructures on the reliability of solder joint was studied. The surface roughness of the Cu stud was increased as the Cu electroplating current density increased. The microstructural morphology of the Cu-Sn IMC layer was affected by Cu stud surface structure. We found the growth rate of IMC layer increased with the increasing of Cu stud grain size and surface roughness during aging test. The growth kinetics of Cu-Sn intermetallic compound formation for 63Sn/37Pb solder followed the Arrhenius equation with activation energy varied from 0.78 eV to 1.14 eV. The ratios of Cu₃ Sn layer thickness to the total Cu-Sn IMC layer thickness was in the range of 0.5 to 0.15 for various Cu microstructures at 150°C during thermal aging test. The shear strength of solder bump was measured after thermal aging and temperature/humidity tests. The relationship between electroplating process and reliability of solder joints was established. The failure mode of solder joints was also analyzed     

Microstructural evolution of a lead-free solder alloy Sn-Bi-Ag-Cu prepared by mechanical alloying during thermal shock and aging

In a previous study, a lead-free solder, Sn-6Bi-2Ag-0.5Cu, was developed by mechanical alloying. The alloy shows great potential as a lead-free solder system. In the present work, the microstructural evolution during thermal shock and aging was examined. In the as-soldered joints small bismuth (1 μm to 2 μm) and Ag₃Sn (1 μm) particles were finely dispersed in a nearly pure tin matrix with a small amount of η-Cu₆Sn₅ phase in the bulk of solder. During thermal shock and aging microstructural evolution occurred with Cu-Sn intermetallic compound (IMC) layer growth at interface, bismuth phase coarsening and Ag₃Sn phase coarsening. The microstructure of the solder appeared to be stable at high temperature. The shear strength of the present solder joint is higher than that of Sn-37Pb and Sn-3.5Ag solders. Shear failure occurred Cu-Sn IMC layer-solder interface and in the bulk of solder.     

Effect of thermal cycling on the growth of intermetallic compounds at the Sn-Zn-Bi-In-P lead-free solder/Cu interface

The low-temperature Sn-9Zn-1.5Bi-0.5In-0.01P lead-free solder alloy is used to investigate the intermetallic compounds (IMCs) formed between solder and Cu substrates during thermal cycling. Metallographic observation, scanning electron microscopy, transmission electron microscopy, and electron diffraction analysis are used to study the IMCs. The γ-Cu₅Zn₈ IMC is found at the Sn-9Zn-1.5Bi-0.5In-0.01P/Cu interface. The IMC grows slowly during thermal cycling. The fatigue life of the Sn-9Zn-1.5Bi-0.5In-0.01P solder joint is longer than that of Pb-Sn eutectic solder joint because the IMC thickness of the latter is much greater than that of the former. Thermodynamic and diffusivity calculations can explain the formation of γ-Cu₅Zn₈ instead of Cu-Sn IMCs. The growth of IMC layer is caused by the diffusion of Cu and Zn elements. The diffusion coefficient of Zn in the Cu₅Zn₈ layer is determined to be 1.10×10⁻¹² cm²/sec. A Zn-rich layer is found at the interface, which can prevent the formation of the more brittle Cu-Sn IMCs, slow down the growth of the IMC layer, and consequently enhance the fatigue life of the solder joint.     

Shear strength and fracture surface analysis of Sn58Bi/Cu solder joints under a wide range of strain rates

The influences of the strain rate on the shear strength and failure mode of Sn58Bi/Cu solder joints were investigated. After reflowing, some Kirkendall voids were observed at the neighborhood of the Cu₃Sn/Cu interface or in the inner Cu₃Sn layer. In addition, another type of void could also be observed inside the Sn58Bi eutectic solders, and its size was much larger than that of Kirkendall voids. Some Bi particles were obviously found to segregate at the interface between the Cu-Sn IMC and the Sn58Bi solder. The single lap shear test results indicated that the strain rate had an important influence on the shear strength and failure mode of Sn58Bi/Cu solder joints. The shear strength of joints demonstrated increment at first and then decrement as the strain rate increased from 3.33 × 10⁻⁴ s⁻¹ to 3.33 s⁻¹. It was observed that all Sn58Bi/Cu solder joints broke in a mixed-type fracture mode under a wide range of strain rates. Additionally, more broken IMC grains were exposed on the fracture face and more fracture occurred within the IMC layer with increasing strain rate. Furthermore, the fracture path gradually moved from the solder side to the inner IMC side as the strain rate increased.     

Effect of phosphorus content on Cu/Ni-P/Sn-3.5Ag solder joint strength after multiple reflows

Electroless Ni-P layers with three different P contents (6.1 wt.%, 8.8 wt.%, and 12.3wt.%) were deposited on copper (Cu) substrates. Multilayered samples of Sn-3.5Ag/Ni-P/Cu stack were prepared and subjected to multiple reflows at 250°C. A tensile test was performed to investigate the effect of P content on the solder joint strength. The low P samples exhibited the highest joint strength after multiple reflows, while the strength of medium and high P samples decreased more rapidly. From interfacial analysis, the Ni₃Sn₄ intermetallic compound (IMC) formed at the interface of low P sample was found to be more stable, while the one of medium and high P samples spalled into the molten solder. The IMC spallation sped up the consumption of electroless Ni-P, leading to the large formation of Cu-Sn IMCs. Fractographic and microstructural analyses showed that the degradation in solder joint strength was due to the formation of layers of voids and growth of Cu-Sn IMCs between the solder and the Cu substrate.     

Correlation between interfacial reactions and mechanical strengths of Sn(Cu)/Ni(P) solder bumps

The correlation between interfacial reactions and mechanical strengths of Sn(Cu)/Ni(P) solder bumps has been studied. Upon solid-state aging, a diffusion-controlled process was observed for the interfacial Ni-Sn compound formation of the Sn/Ni(P) reaction couple and the activation energy is calculated to be 42 KJ/mol. For the Sn0.7Cu/Ni(P), in the initial aging, a needle-shaped Ni-Sn compound layer formed on Ni(P). Then, it was gradually covered by a layer of the Cu-Sn compound in the later aging process. Hence, a mixture layer of Ni-Sn and Cu-Sn compounds formed at the interface. For the Sn3.0Cu/Ni(P), a thick Cu-Sn compound layer quickly formed on Ni(P), which retarded the Ni-Sn compound formation and resulted in a distinct Cu-Sn compound/Ni(P) interface. The shear test results show that the mixture interface of Sn0.7Cu bumps have fair shear strengths against the aging process. In contrast, the distinct Cu-Sn/Ni(P) interface of Sn3.0Cu solder bumps is relatively weak and exhibits poor resistance against the aging process. Upon the reflowing process, the gap formation at the Ni(P)/Cu interface caused a fast degradation in the interfacial strength for Sn solder bumps. For Sn0.7Cu and Sn3.0Cu solder bumps, Ni₃P formation was greatly retarded by the self-formed Cu-Sn compound layer. Therefore, Sn(Cu) solder bumps show better shear strengths over the Sn solder bump.     

SnAgCu无铅焊点的电迁移行为研究

电迁移引发的焊点失效已经成为当今高集成度电子封装中的最严重的可靠性问题之一。应用SnAgCu无铅焊膏焊接微米级铜线,进行电迁移实验。结果表明:焊点形貌从原来的光滑平整变得凹凸不平,阴极处出现了裂纹和孔洞,并且在铜基板和Cu6Sn5金属间化合物(IMC)之间出现薄薄的一层Cu3Sn金属间化合物,由ImageJ软件测量其平均厚度约为2.11μm;而在阳极附近没有明显的Cu3Sn金属间化合物形成。     

SnAgCu焊点电迁移诱发IMC阴极异常堆积

为了研究电迁移过程中焊点与焊盘界面金属问化合物(IMC)的变化,在28℃下,对无铅Sn3.0Ag0.5Cu焊点进行了6.5A直流电下的电迁移实验.结果发现,通电144h后,阳极侧IMC层变厚,平均达到10.12 μm;阴极侧IMC层大部分区域变薄至0.86μm,局部出现Cu焊盘的溶解消失,但在界面边缘处出现Cu3Sn5...     

Cu Substrates with Different Grain Sizes

Cu₆Sn₅ and Cu₃Sn are easily formed at the interface between Sn and Cu during reflow and aging processes. Thick Cu-Sn compounds at the interface become brittle, reducing the mechanical strength of solder joints and increasing the consumption of under bump metallization (UBM). It is noted that intermetallic compound (IMC) growth and substrate consumption are affected by factors such as substrate fabrication, substrate orientation, and substrate microstructure. In this study, to determine the effects of substrate grain size on IMC growth and substrate consumption, pure Sn solder was reflowed on annealed Cu substrates with different grain sizes at 250°C for 30 s to 600 s. It was revealed that Cu substrates with smaller grain sizes exhibited reduced IMC growth. In addition, the interdiffusion coefficients of Cu₆Sn₅ and Cu₃Sn were decreased for the Cu substrate with the smaller grain size. The influence of the Cu substrate grain size on IMC growth and substrate consumption is discussed.     

添加Sb和LaB6对Sn3.0Ag0.5Cu/Cu界面IMC生长的影响

研究了Sb和稀土化合物的添加对Sn3.0Ag0.5Cu无铅焊料焊接界面金属间化合物层生长的影响。研究结果表明,固态反应阶段界面化合物层的生长快慢排序如下:v(SAC0.4Sb0.1LaB6/Cu)v(SAC0.4Sb/Cu)v(SAC0.1LaB6/Cu)v(SAC/Cu)。计算各种界面IMC生长的激活能Q结果表明,Sn3.0Ag0.5Cu/Cu界面IMC生长的激活能最高,为92.789 kJ,其他焊料合金Sn3.0Ag0.5Cu0.4Sb0.1LaB6/Cu,Sn3.0Ag0.5Cu0.1LaB6/Cu和Sn3.0Ag0.5Cu0.4Sb/Cu界面IMC生长的激活能分别为85.14,84.91和75.57 kJ。在老化温度范围内(≤190℃),Sn3.0Ag0.5Cu0.4Sb0.1LaB6/Cu的扩散系数(D)最小,因而其界面化合物的生长速率最慢。