高性能金属外壳镀覆工艺研究及其对外壳性能的影响

本文系统研究了表面预处理、镀液配方及电镀工艺对电子元器件金属外壳耐蚀性能的影响。结果表明,采用化学抛光溶液抛光和超细粉喷刷两种技术联合进行基体表面处理,使基体的光洁度得到明显改善,更易获得致密的镀层;镍层厚度的增加能明显提高镀层的抗盐雾能力,但过厚的镀镍层会使金属外壳的引线抗弯疲劳性能下降;T镍镀液和T金镀液能使镀层更均匀和致密,从而显著改善电镀层的抗腐蚀性能以及抗疲劳性。     

微波混合电路铝合金封装外壳电镀锡铋技术

混合集成电路中，封装一般采用表面电镀镍金可伐外壳。但是可伐表面镀金在实用中也有其固有的缺点，表面镀金层与电路焊接时，镀层金与焊料中的锡，电位差较大，存在原电池腐蚀的不利因素。铝合金上采用无铅锡铋镀层是一种较好的替代方案。本文采用盐雾试验法，对铝合金表面化学镀镍做底层及电镀光亮锡铋层做表层的样品进行抗腐蚀性研究，结果表明采用化学镀镍14微米和光亮锡铋7微米组合镀层的具有良好的抗腐蚀效果，可以承受72小时的盐雾试验。此外采用扫描电镜、X射线能谱仪对锡铋光亮镀层的成分进行分析，结果表明铋含量为1％，锡含量为99％。     

AZ91D化学镀Ni-P结构耐蚀性研究

利用金相、SEM、TEM、XRD、盐雾、电化学测量系统研究了镁合金AZ91D的化学镀Ni-P镀层组织结构及耐蚀性能,结果表明,化学镀镍层为胞状致密结构,镀层厚度均匀,与基体结合良好.P的质量分数为6.68%,为中P镀层,镀层阻抗为0.6 Ω,镀层组织为非晶加少量微晶;镀层耐腐蚀性能良好,连续盐雾8 h未出现腐蚀斑点.盐雾腐蚀速率明显低于基体的腐蚀速率.化学镀镍磷层的最小腐蚀电流密度为4.52μA/cm2,腐蚀电位为-250 mV.低于200℃退火,镀层的耐腐蚀性能有所提高,而高于200℃退火,其耐腐蚀性能随温度提高而降低.     

国产与进口管壳金镍镀层质量特性分析

国产金镍体系管壳在鉴定检验中,常出现腐蚀、掉字等镀层质量问题,直接影响器件的封装可靠性。结合镀层常见质量问题,分析镀层的厚度、结构等影响因素;利用扫描电镜和能谱分析,从外观、厚度、结合力、耐热性、结构和成分六方面,进行了国产与进口管壳样品的镀层质量特性分析;选取国产与进口管壳样品各10只,开展湿热试验和盐雾试验,分析Au/Ni管壳的薄弱环节和抗腐蚀性能。结果表明,国产管壳相比进口管壳的不足,主要表现在打标方式不成熟、金层厚度较为单薄、镀层结构不够合理、材料纯度相对较低等方面;在打印标记处和平行焊缝处,管壳的抗腐蚀性能较弱。     

用镀层孔隙表征外壳耐腐蚀性的方法探讨

介绍了电子器件外壳表面镀层孔隙显色的原理、方法及工艺条件,通过研究电镀层孔隙变色面积与实际盐雾腐蚀面积的关系,建立了用孔隙显色来评价电子器件外壳表面镀层的抗腐蚀性的方法。     

声表面波延迟线器件用高频三腔体金属外壳的研制

本文详细介绍了一种高频三腔体金属外壳的研制,该外壳是声表面波器件专用封装的典型之作：三腔体单面密封结构,上腔体内腔的钎焊卡槽用来装配隔板,从而满足电磁屏蔽要求;采用金锡焊工艺钎焊高频引线组件,确保了信号输入输出端的高频阻抗要求;平行缝焊工艺设计,确保产品气密封接;镀层满足抗盐雾要求。     

镀金层盐雾试验机理及方法探讨

本文从盐雾试验的方法和目的着手，探讨盐雾试验是如何显示金镀层质量，并结合微电池腐蚀原理提出盐雾试验机理。根据剖析的盐雾试验的机理，作者从微电池腐蚀的两个微观因素糙度等。结合这些宏观条件，作者探讨了金镀层耐盐雾试验的有效方法。     

PCB镀金层耐腐蚀性和失效机理浅析

文章通过对电镀软金过程采用不同的电镀时间,电流密度,电镀次数形成不同的金、镍层厚度的板件,用盐雾和酸雾实验研究不同工艺加工的金面耐腐蚀性差异,结果发现金厚是影响金面耐腐蚀性的关键因素,文章还对金面的耐腐蚀性机理进行了探讨。     

基于有机基板的化学镍钯浸金工艺应用与测评

有机基板被广泛应用于电子封装领域,常见的表面处理工艺包括电镀镍金、化学镍金、浸锡、浸银等工艺。在众多表面处理工艺中,化学镍钯浸金工艺因其具有较好的综合性能展现出显著优势。化学镍钯浸金工艺是在化学镍金工艺的基础上增加化镀钯处理,采用该工艺先对基板表面进行化镀镍处理,再进行化镀钯处理,最后完成化学浸金处理。钯镀层可以防止金在沉积过程中腐蚀镍镀层以及阻挡镍向金属间化合物（IMC）层扩散。利用X-Ray、电子扫描显微镜（SEM）、聚焦离子束（FIB）等图像分析方法,对比了不同厂商的化学镍钯浸金镀层的厚度、微观形貌及质量,结果表明,平整且致密的钯镀层可以有效避免镍腐蚀现象。     

微波集成电路图形镀金工艺研究

通过对混合微波集成电路图形镀金工艺的分析研究,提出了以液态感光油墨作为掩蔽层,硫酸盐镀镍体系及柠檬酸盐镀金体系镀镍/金的最佳施镀方案,并通过一系列可靠性试验,证明了该镍/金镀层良好的抗蚀能力和焊接可靠性.     

真空下硬金镀层的低速电接触磨损影响因素

导电摩擦副在磨损过程中产生较大磨损和较多磨屑,既影响电接触的稳定性又会降低导电环间的绝缘电阻。借助某卫星滑环的结构,导电摩擦副选用铜环电镀硬金的导电环和金银铜锌合金的电刷触点,在真空环境下开展硬金镀层的镀镍层厚度、硬度、表面光洁处理、真空加热处理、通电电流大小对电接触磨损性能影响的研究。研究结果表明:硬金镀层在真空环境下,硬度和真空加热预处理是影响磨损的显著因素,电流大小对磨损有一定影响,镀镍层厚度和光洁处理对磨损无显著影响。     

PCB镀镍金孔隙率探讨

SMT技术的兴起使有机可焊性保护涂层、化学沉镍金及电镀镍金表面处理在工业化生产中得到广泛的应用。但是这三种工艺形成的保护层较薄,不可避免的出现微孔,微孔,对表面品质有至关重要的影响,孔隙率是评价其镀层连续性的重要参数之一。本文通过试验验证的方式探讨电镀时影响镀层致密度的相关因素,总结分析出一套避免孔隙率产生的最优生产参数,为生产实际提供了理论依据。     

Corrosion protection of anisotropically conductive adhesive joined flip chips

Corrosion is a common cause of failure in electronic devices. Conformal coatings may be used to prevent corrosion of electronics packages. Water and contaminants are thus not in direct contact with the package surface, which may improve resistance to corrosion. However, it is important to study the effects of corrosion on both coating materials and on the electronics itself. The protection method and the level of protection can then be selected.This study presents a salt spray test of anisotropically conductive adhesive joined flip chip components on FR-4 substrate, where half of the test samples were parylene C coated. A dramatic difference was seen between these two test lots. Parylene C proved to be an excellent barrier against salt spray. The test lots without conformal coating suffered severe corrosion, and were thus considerably less reliable. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) revealed the reasons for the failures in the non-coated test samples. The main reason was found to be severe corrosion of the nickel layer. There were no failures among the parylene C coated test samples during the 3000 h test. Moisture absorption of the FR-4 substrate material is also studied in this paper. Both plain FR-4 and parylene C coated FR-4 materials were studied. These tests were performed both at room temperature and in boiling water.     

以钯作扩散阻挡层——一种多功能线路板表面处理方法

电子工业不断的小型化,数种不同互联技术于线路板上电子零件连接及电接点被应用范畴不断增加。基于此用途,线路板组装垫位需被一层最后表面处理保护,如这最后表面处理层可用于不同互联技术,可被称为多功能表面层。钯是一个艮好的镍扩散阻挡层,故此层膜能抵受如焊接及键接之严酷老化测试条件。其两大优点为具有良好热超声波键接性及于无铅焊料之非常优艮焊接性。从预镀导线架过往多年经验已知即使很薄贵金属钯层及金层已可有保证可靠的金线键接性。从这一知识,沉镍浸钯浸金层膜系统（ENIPIG）被研发出来。此崭新表面处理ENIPIG三种金属镀液需互相配合才能于线路板工艺上达成理想多功能层膜。因着其薄贵金属层膜,相对于其他表面处理,可节省颇大的成本。     

大气盐雾与电子产品盐雾试验

对自然界中盐雾的形成和特点及其对电子产品的影响进行了综述,并对电子产品、设备、元器件以及材料的盐雾试验参数进行了对比。根据盐雾试验的应用范围,通过材料、元器件、组件及整机的逐级检验,介绍了提高产品的耐盐雾腐蚀性能,评价电子产品长期耐盐雾性能的研究方法。     

Atmospheric corrosion resistance of electroplated Ni/Ni–P/Au electronic contacts

Atmospheric corrosion has vast consequences on the reliability of electronic connectors. This study determined the corrosion resistance of Ni/Ni–P plating metallurgy as a function of plating current density and plating thickness. Discrepancy was observed in the neutral salt spray (NSS) and mixed flowing gas (MFG) tests. Thicker Ni–P deposits displayed superior corrosion resistance in MFG tests while thinner Ni–P deposits performed better in NSS tests. This disparity was attributed to the intrinsic corrosion susceptibility of Ni–P against chlorine or sulfur assisted corrosion. Corrosion products were analysed for better understanding of the corrosion mechanism. NSS test produced green corrosion residues consisting of CuCl (nantokite) and CuCl₂(OH)₃ (clinoatacamite) and brown residues consisting of Cu₂O (cuprite). MFG test produced sulfides of copper (major) and nickel (minor).     

Assembly of 3D-wares with the use of wire leadouts

Some methods of the formation of microwelds, which are most acceptable for the assembly of 3D-wares with the use of wire leadouts, have been analyzed. Some peculiarities of the bonding of inner wirings on a die and a package by different welding methods, such as pressure welding with indirect pulsed heating and thermosonic, ultrasonic, and split-tip welding, have been considered. The effect of structural and technological factors on the quality of microwelds made by ultrasonic welding with the use of aluminum wire, aluminum metallization on a die, and gold, nickel, and nickel alloy coatings has been studied. Some information on microwelds made with the use of copper wire and copper metallization has been represented.     

金属外壳封接用双层玻坯的研制

以BH—G/K玻璃为基体,以添加Al2O3粉的DM—308玻璃为表层区研制出与金属外壳封接的双层玻坯。分析了Al2O3粒度及添加量对熟坯致密化和线收缩率的影响。结果表明,表层区使用添加质量分数为20%和30%0.5μm粒径Al2O3粉的DM—308玻璃可以实现熟坯的匹配收缩,用于UP2113—14外壳熔封。电镀后外壳气密性、绝缘电阻均有数量级提高,玻璃沿引线上爬高度只为BH—G/K玻璃的1/3,显著降低外壳盐雾试验后引线根部易锈蚀和引线受力后绝缘子开裂的风险。     

Coatings of contact areas of crystals and the traverse of packages for microwelding of internal outputs of 3D wares

The design-and-manufacturing features of the development of discrete semiconductor devices and 3D wares are considered. Coatings of contact areas of crystals and package traverses for the formation of internal connections in 3D wares are analyzed. It is established that the following coatings should be primarily considered in assembling 3D wares: aluminum and copper metallization on crystals; and gold, silver, nickel, its alloys, and galvanic aluminizing on the package traverses. The data on the deposition technology of these coatings are presented.