光纤定位激光钎焊键合过程中钎料与镀层的界面反应

光电子封装中,光导纤维的定位键合是一项关键技术,并且焊点界面处的显微组织对于焊点的可靠性有重要影响.本文选用80Au20Sn和52In48Sn钎料实现了激光钎焊条件下的光纤键合,采用扫描电子显微镜及能谱分析的方法对于两种钎料分别与硅片上的Au/Ti镀层和光纤上的Au/Ni镀层反应形成的界面微观组织形态及形成规律进行了分析.结果表明:对于80Au20Sn钎料,除了共晶组织ζ相+δ相,在AuSn/Au/Ti镀层界面形成了大量枝状的先共晶ζ相,在AuSn/Au/Ni镀层界面形成了针状的(Au,Ni)3Sn2;对于52In48Sn钎料,在InSn/Au/Ti镀层界面形成了连续层状的Au(In,Sn)2,随着输入能量的增加,其逐渐转变为不连续的块状化合物AuIn2,在熔融钎料流的作用下部分AuIn2脱离界面进入钎料中,在InSn/Au/Ni镀层界面形成了一层极薄的Au(In,Sn)2.     

激光喷射钎料球键合焊点热循环试验研究

为研究激光喷射钎料球键合焊点的可靠性,用Sn3.0Ag0.5Cu钎料球对Au/Cu焊盘进行了激光喷射钎料键合试验,采用微强度测试仪、扫描电子显微镜、能谱分析仪研究了热循环条件对接头强度以及界面微观组织演变的影响.结果表明：采用激光喷射钎料键合技术焊盘表面Au层不能完全溶入钎料中,导致在界面处形成AuSn2＋AuSn4多...     

圆片级气密封装及通孔垂直互连研究

提出了一种新颖的圆片级气密封装结构.其中芯片互连采用了通孔垂直互连技术:KOH腐蚀和DRIE相结合的薄硅晶片通孔刻蚀技术、由下向上铜电镀的通孔金属化技术、纯Sn焊料气密键合和凸点制备相结合的通孔互连技术.整个工艺过程与IC工艺相匹配,并在圆片级的基础上完成,可实现互连密度200/cm2的垂直通孔密度.该结构在降低封装成本,提高封装密度的同时可有效地保护MEMS器件不受损伤.实验还对结构的键合强度和气密性进行了研究.初步实验表明,该结构能够满足MIL-STD对封装结构气密性的要求,同时其焊层键合强度可达8MPa以上.本工作初步在工艺方面实现了该封装结构,为进一步的实用化研究奠定了基础.     

溶质元素(Ni,Sn)总量对Cu-Ni-Sn合金导电性能的影响

为提升Cu-Ni-Sn合金的导电率,系统研究了溶质元素(Ni,Sn)含量对导电Cu合金导电率和硬度的影响。通过对现有典型牌号Cu合金进行成分解析,发现在Ni、Sn原子比为3/1时合金具有高的导电率和强度,故本工作固定Ni、Sn原子比为3,改变Ni和Sn总量,设计了一系列三元成分合金;采用真空电弧熔炼工艺制备合金锭,随后进行1093K/1h固溶+65%~75%变形冷轧+673K/2h时效处理。实验结果表明,经过固溶+变形+时效处理后的Cu合金的导电率随溶质元素(Ni+Sn)含量增加而降低,而硬度变化则呈相反趋势;系列Cu合金的弹性模量随(Ni+Sn)含量基本保持不变。由此,为使Cu合金的导电率不低于15.0%IACS、且保持一定的强度,溶质元素(Ni+Sn)含量应为10.0%≤y(Ni+Sn)≤16.0%(质量百分比含量为12.0%≤w(Ni+Sn)≤18.0%)。     

AlN与Mo-Ni-Cu活性封接的微观结构和性能分析

AlN陶瓷是一种性能优良的电子封装材料,但不容易与金属直接连接在一起.实验采用98（Ag28Cu）2Ti活性焊料, 在真空条件下实现了AlN陶瓷与Mo Ni Cu合金的活性封接.利用EBSD、EDS、XRD方法研究了焊接区域以及剪切试样断裂表面的微观结构和相组成,测定了焊区的力学性能和气密性.研究结果显示：在AlN陶瓷界面上有TiN生成,说明陶瓷与焊料之间是一种化学键合,而在Mo Ni Cu合金的界面上有少量的Ni Ti金属间化合物存在.剪切后试样的断裂面上有TiN和AlN,说明断裂发生在靠近陶瓷的焊层区域.焊接试样性能优良：气密性达到1.0×10^-11Pa·m³/s,平均抗弯强度σ_ｂ=78.55MPa,剪切强度σ_τ=189.58MPa.     

Different Diffusion Behavior of Cu and Ni Undergoing Liquidesolid Electromigration

The diffusion behavior of Cu and Ni atoms undergoing liquidesolid electromigration（L-S EM） was investigated using Cu/Sn/Ni interconnects under a current density of 5.0 103A/cm2 at 250℃. The flowing direction of electrons significantly influences the cross-solder interaction of Cu and Ni atoms, i.e., under downwind diffusion, both Cu and Ni atoms can diffuse to the opposite interfaces; while under upwind diffusion,Cu atoms but not Ni atoms can diffuse to the opposite interface. When electrons flow from the Cu to the Ni, only Cu atoms diffuse to the opposite anode Ni interface, resulting in the transformation of interfacial intermetallic compound（IMC） from Ni3Sn4into（Cu,Ni）6Sn5and further into [（Cu,Ni）6Sn5t Cu6Sn5], while no Ni atoms diffuse to the opposite cathode Cu interface and thus the interfacial Cu6Sn5 remained.When electrons flow from the Ni to the Cu, both Cu and Ni atoms diffuse to the opposite interfaces,resulting in the interfacial IMC transformation from initial Cu6Sn5into（Cu,Ni）6Sn5and further into[（Cu,Ni）6Sn5t（Ni,Cu）3Sn4] at the anode Cu interface while that from initial Ni3Sn4into（Cu,Ni）6Sn5and further into（Ni,Cu）3Sn4at the cathode Ni interface. It is more damaging with electrons flowing from the Cu to the Ni than the other way.     

Sn8Zn3Bi-xCu/Cu焊接接头界面反应及力学性能研究

以Sn8Zn3Bi为研究对象,采用微合金化方法研究了不同含量的Cu元素对其显微组织、钎料合金与Cu基板钎焊后的界面金属间化合物(IMC)层尺寸及焊接接头剪切强度的影响。结果表明,Sn8Zn3Bi-xCu/Cu(x=0.3,0.5,0.8,1.0,1.5)焊接界面IMC主要为层状Cu5Zn8相。随着Cu含量的增加,界面IMC层的厚度逐渐减小,接头的剪切强度逐渐提高,Sn8Zn3Bi-1.5Cu/Cu接头剪切强度较Sn8Zn3Bi/Cu显著提高。经120℃时效处理后,Sn8Zn3BixCu/Cu(x=0,0.3,0.5,0.8,1.0,1.5)焊接接头剪切强度都明显下降,接头断裂方式由韧性断裂转为局部脆性断裂,但添加了Cu元素的钎料界面IMC生长速度较Sn8Zn3Bi钎料慢,因此Cu元素的添加抑制了界面IMC层的生长。     

泡沫Ni/In-48Sn复合焊料钎焊Al合金接头显微结构及力学性能研究

In-48Sn共晶焊料具有熔点低、延展性高、润湿性好等优点,在微波、通信等功能组件的钎焊连接中具有广泛应用。然而,In-48Sn共晶焊料力学性能较差,已难满足新一代功能组件的载荷要求。采用微合金化及微纳米颗粒、纤维强化等方法可在一定程度上提高焊料的强度,但钎焊接头的强度提升效果有限。基于此,本工作采用真空浸渗工艺制备了泡沫Ni强化In-48Sn复合焊料,并采用该复合焊料对表面含Ag镀层的Al合金进行了低温钎焊连接,重点研究了泡沫Ni孔隙率和钎焊时间对接头显微结构及力学性能的影响。研究结果表明,Al合金表面形成了Ag₂In金属间化合物(IMC)层,其随钎焊时间延长不断增厚,且在无Ni骨架阻挡时易向焊缝中生长形成块状结构。In-48Sn焊料与泡沫Ni骨架反应形成了(Ni, Cu)₃-(In, Sn)₇相,延长钎焊时间、减小泡沫Ni孔隙度均会促进该反应相的形成并加快In基焊料的消耗,最终焊缝完全由Ni骨架和IMCs组成,而钎焊接头的剪切强度也相应增加。采用50%Ni-In48Sn复合焊料钎焊120 min时接头剪切强度达到了3...     

激光辅助阳极键合方法及实验研究

为了提高MEMS微器件成品的封装质量和效率,本文自主设计了新型的激光辅助阳极键合技术系统,并将其运用于硼硅玻璃BF33与硅的键合实验,成功实现了硅与玻璃在低功率下局部区域的完好键合.采用扫描电子显微镜对键合样本界面的微观结构进行分析,结果表明:在玻璃/硅的键合界面有明显的过渡层生成.使用能谱仪测定玻璃基体、过渡层以及硅层所含的化学元素种类及其质量分数,通过对比分析认为:激光在键合层的致热温度和界面区的强电场导致硼硅玻璃耗尽层中的氧负离子向键合界面迁移扩散,并与硅发生氧化反应形成中间过渡层,而该界面过渡层的形成是实现玻璃/硅键合的基本条件.该种新型键合技术操作简单、速度快、灵活性高,可以针对不同键合材料实时调整激光功率、行走速度、扫描时间等参数,可广泛应用于MEMS封装器件中硅与玻璃的键合.     

合金元素对Cu/Sn-/Cu回流焊焊点界面微观结构及剪切性能的影响

选用Sn64Bi35Ag1、Sn64.7Bi35Ag0.3和Sn99Ag0.3Cu0.7三种不同的钎料进行回流焊焊接试验,研究高Bi元素、低Ag元素钎料及低Ag钎料对Sn基钎料焊点微观组织及剪切性能的影响.结果表明:各焊点界面处均生成了 一层扇贝状的Cu6Sn5金属间化合物,在含Bi元素的钎料焊点中,Bi元素在焊点界面及内部聚集,导致界面处金属间化合物层的厚度增加,大量富Bi相呈脆性,降低钎料中的Ag含量对焊点中Bi元素的富集现象有减弱作用.Sn99Ag0.3Cu0.7钎料焊点界面处的金属间化合物层厚度最小,且焊点内部形成了细小的Ag3Sn相颗粒,共晶组织呈均匀分布,使得焊点剪切性能最优,其剪切强度达20.4 MPa.     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...