印制电路板化学金漏镀浅析

在化学镍金过程中会出现漏镀现象,文章讨论了漏镀产生的机理,采用正交实验法对影响漏镀的主要因素进行排列,同时,对于铜面与钯离子在进行置换反应时的电化学势能进行分析。结果表明,在调节活化钯相关参数的同时,反应中的电化学势能亦不容忽视。     

PCB化学镀镍漏镀现象分析

文章阐述了不同尺寸铜盘连接状况、掩蔽作用等对漏洞的影响,发现孤立的小铜盘（0．1mm）比大尺寸的铜盘（〉0．1mm）更易发生漏镀,即漏镀易发生在小尺寸铜盘上,主要的原因与置换钯的速率不同相关。至于因掩蔽引发的漏镀现象,主要与平衡电化学势作用相关。在活化过程中,电子转移主要决定了漏镀发生与否。     

浅谈镀钯铜线的特性

随着金线价格一路上涨并创下历史新高,大型封装厂正在加大对铜线制程的投入。通过封装厂多年的摸索,发现镀钯铜线是金线很好的替代品。文章分析了镀钯铜线作为键合线材料本身的基本性质,镀钯铜线引线键合的特征和镀钯铜线PCT实验的可靠性。通过分析发现镀钯铜线材料本身有优良的导电和导热特性,同时还有很好的抗氧化性。镀钯铜线在键合过程中需要保护气体的保护,通过硬度实验发现镀钯铜线的硬度较大,因此需要在键合过程中防止弹坑的出现。通过PCT实验证实镀钯铜线具有较好的可靠性。     

镀钯引线框架的超薄电镀技术

<正> 日本新光电气工业公司开发出了一种镀钯引线框架超薄技术。这样一来,钯的市场价格变化奇快,镀钯引线有利于环保,并可大大地降低电镀材料的费用成本。1 工业用钯的市场价格上扬 近年来,在国际上对于铅给环境所造成的影响越来越关心,在电子领域中,如何推进电子产品的无铅化运动正在高涨。在半导体的安装工艺中,为了能够省掉含铅的锡焊工序,正在开发、制造、销售镀钯引线     

从EDTA溶液中电镀银钯合金

本文研究了从合有EDTA,碳酸铵和氨水的碱性溶液中镀取银钯仑金的方法。合金沉积的阴极电位为-0.37V,它介于单位银溶液和单独钯溶液的阴极电位之间。银钯合金沉积属于非正则共沉积,合金层中钯的含量总是小于电镀液中钯的含量。共沉积的钯含量随着镀液的pH值增加或者电流密度的增加而增加,并且,随着镀液温度增加而减少。镀液阴极电流效率大约是70％,与镀液温度无关。它随着pH值增加而提高,随着电流密度的增加而降低。SEM照片表明,合金镀层表面光滑无裂纹并且与基体结合力好。     

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。     

镀钯铜丝芯片键合工艺控制和可靠性研究

随着金价的不断上升,集成电路封装成本越来越高。为此,集成电路封装厂商纷纷推出铜线键合来取代金丝键合,以缓解封装成本压力。但是纯铜丝非常容易氧化,为了提高键合生产效率及产品可靠性,目前封装厂商主要采用镀钯铜丝作为键合丝。对集成电路镀钯铜丝键合生产技术和工艺控制方法进行了探讨,并和金丝及纯铜丝工艺控制进行了比较分析。对镀钯铜丝键合工艺主要失效模式进行了介绍和说明,并就弹坑检测试验方法进行了比较分析和总结。特别是对特殊产品的弹坑检测试验如何才能确保结果准确,进行了实例分析。     

镀钯铜线键合中FAB表面的钯覆盖

铜引线键合由于低廉的成本和优良的材料综合性能而受到越来越多的重视,而镀钯铜线较纯铜线的应用更为广泛。其中,自由空气球(FAB)上钯的覆盖情况是需要进行研究的问题之一。由于烧球工艺为瞬态过程,因此在形成FAB后其表面的钯可能会出现不均匀的分布,后续的塑封环节中低含量的钯区域就会遭受外界的侵蚀,这对焊点的可靠性会有不良的影响。基于此,针对线径20μm镀钯铜线FAB上的钯覆盖区域进行了探究,并采用定制化的化学腐蚀方案来显示FAB上钯膜较厚区域和较薄区域在形貌上的差异。此外还讨论了不同电子火焰熄灭(EFO)工艺参数样品的钯薄弱区形状参数,最后分析了影响FAB表面上钯薄弱区的主要工艺因素,得到了相关工艺参数参考值,对后续工艺的可靠性提升有一定的借鉴意义。     

微量沉积氯对焊点腐蚀过程的影响

不同金属间存在电位差,被硫、氯等污染的焊点易产生原电池腐蚀,这将降低焊接产品的可靠性,缩短产品的寿命。因此,焊点的腐蚀问题受到人们的高度重视。以镀钯铜线的球栅阵列（BGA）产品为研究对象,通过能谱仪（EDS）、X射线衍射（XRD）、X射线光电子能谱（XPS）等实验手段,首先分析了多焊点同时被氯腐蚀的影响因素,再将焊点表面划分为上表面、侧表面以及界面3个区域,并对各区域进行腐蚀分析和验证,最后得出氯腐蚀焊点的腐蚀机理。实验结果表明：1）氯腐蚀难易程度的主要影响因素为IMC的致密度和镀钯层上的铜露出面积,IMC的致密度越小,镀钯层上的铜露出面积越大,氯腐蚀越容易发生;2）焊点腐蚀路径表现为氯沿铜球表面向铜球与IMC的界面迁移的过程;3）焊点烘烤时间越短,焊点表层上钯的覆盖率越大,焊点被氯腐蚀的概率越低。     

化学镍/化学钯/浸金的表面涂覆层的可焊性和可靠性

概述了化学镍/化学钯/浸金(ENEPIG)表面涂(镀)覆层的优点。它比化学镍/浸金(ENIG)有更好的可焊接性和焊接可靠性。化学镍/化学钯/浸金表面涂(镀)覆层应该是有发展前景的。     

取代化学镍金用于线宽线距小于30μm高密度印制板的新技术

化学镀镰/金具有优良的性能,已在印制电路板上获得广泛应用。但随着线路的线宽线距越来越小耙催化剂会夹杂在线路之间造成化学镀镖经常出现超镀现象,使化学镀腺/金工艺无法应用。为了解决此问题,我们发现用0.2μm厚的微碱性化学镀银层具有化学镀镖/金层相同的可焊性和打线功能,证明微碱性化学镀银工艺可以取代超高密度PCB的化学镀牒/金工艺。     

Spontaneous, non-aqueous electrochemical deposition of copper and palladium on Al and Al(Cu) thin films

Copper and palladium seed layers have been successfully deposited from organic solutions onto patterned and unpatterned pure aluminum and Al(0.5%Cu) thin films using an immersion displacement process. The reaction occurs at ambient temperature and pressure by a spontaneous electrochemical mechanism. Copper and palladium deposition using the organic solution was studied as a function of reaction time and Cu or Pd concentration in the solution. It was found that both time and the intial ionic metal concentration significantly influence deposit morphology, particle size and shape, and adherence. Nucleation of Cu or Pd sub-micron particles on both Al and Al(Cu) surfaces occurred in less than one minute while nucleation density and particle size increased with longer deposition times. Increasing the copper or palladium concentration in the organic solution resulted in an increase in the final particle size of the seed crystals. However, an increase in deposition time and metal concentration in the organic solution caused more extensive dissolution and pitting of the aluminum thin films. The Cu and Pd deposits were effectively used as catalytic sites for subsequent electroless or electrolytic copper deposition using conventional aqueous processes.     

Electroless nickel plating process model for plated-through-hole board manufacturing

In this paper, the electrochemical reaction mechanism is used to develop a mathematical model for an electroless nickel plating process of plated-through-hole board. The model is calibrated against experimental data and the result, which is in good agreement with measured data, applied for state estimation of the unobservable processes. The electrical, chemical, and board parameters are estimated from measurements that are standard in the nickel plating industry.     

纳米钯材料的制备及其在PCB化学镀铜中的应用

以二水合氯化钯为原料,PVP（聚乙烯吡咯烷酮）为分散剂,抗坏血酸（从）为还原剂,在常温下还原Pd^2＋制备纳米钯。通过激光动态散射法（DSL）,透射电子显微镜（TEM）和X射线衍射仪（XRD）对纳米钯进行了表征分析,结果显示,在PVP分散剂的作用下,得到的纳米钯为粒径8nm～22nm,无其他的氧化物存在。该纳米钯材料可作为化学沉铜的活化液,可以减少沉铜的工艺步骤,经过金相显微镜观测化学镀铜后的孔背光级数均达到10级,通过扫描电镜观察镀铜层表面颗粒均匀、平整。所制备的纳米钯是一种优异的化学镀铜活化剂。     

电子接插件的快速连续电镀方法

介绍了适于电子接插件的快速连续电镀金、钯及Ｓｎ－Ｐｂ合金工艺的流程、操作要领等,对镀层的性能进行了分析比较,提出了快速电镀应解决的问题。     

接触表面电阻率及其对屏蔽效能的影响

为了减少来自机壳缝隙的潜在EMI泄漏,工程师通常在缝隙位置增加衬垫来加以密封.如果要这些衬垫完全地起作用,必须有可利用的导电区域.然而,常见的问题是暴露的金属因为氧化和/或腐蚀以及物理外观等因素,很难达到预期的效果.因此,很多情况下要增加一层导电的镀层来保护裸露的金属.增加的电镀处理的确能够影响机壳的屏蔽效能,尤其是当工作频率还在持续升高的时候.     

Factors influencing open circuit decomposition behavior of sulfur-containing additive component used in Cu plating for advanced interconnect metallization

Accelerated decomposition of organic additives during open circuit condition was observed only when both copper wire and oxygen are present in the copper sulfate solution. The data suggest that the accelerating mercapto species could form a complex with cuprous ions from copper anode in the plating solution. The copper complexes formed then undergo oxidation reaction and lose its original electrochemical activity by introducing byproducts. Adsorption behavior of various chemical components in the plating solution on the copper anode surface was found to have a significant influence on the sulfur-containing brightening agent degradation rate. The degradation mechanisms attributed to the interactions among different chemical components are also addressed and discussed.     

Galvanically Replaced,Single‐Bodied Lithium‐Ion Battery Fabric Electrodes

Despite extensive research on flexible/wearable power sources, their structural stability and electrochemical reliability upon mechanical deformation and charge/discharge cycling have not yet been completely achieved. A new class of galvanically replaced single‐bodied lithium‐ion battery (LIB) fabric electrodes is demonstrated. As a proof of concept, metallic tin (Sn) is chosen as an electrode active material. Mechanically compliable polyethyleneterephthalate (PET) fabrics are conformally coated with thin metallic nickel (Ni) layers via electroless plating to develop flexible current collectors. Driven by the electrochemical potential difference between Ni and Sn, the thin Ni layers are galvanically replaced with Sn, resulting in the fabrication of a single‐bodied Sn@Ni fabric electrode (Sn is monolithically embedded in the Ni matrix on the PET fabric). Benefiting from the chemical/structural uniqueness and rationally designed bicontinuous ion/electron transport pathways, the single‐bodied Sn@Ni fabric electrode provides exceptional redox reaction kinetics and omnidirectional deformability (notably, origami‐folding boats), which lie far beyond those attainable with conventional LIB electrode technologies.     

Manipulating Ion Transfer and Interface Stability by A Bulk Interphase Framework for Stable Lithium Metal Batteries

Lithium metal batteries (LMBs) have attracted widespread concern as the next-generation energy storage devices with high energy density. At the surface of lithium metal anodes (LMAs) toward electrolytes, lithium plating always competes with interfacial reactions. This makes interfacial reactions light shadow right behind lithium plating, leading to performance degradation. Herein, lithium plating is spatially decoupled from interfacial reactions by constructing a 3D solid electrolyte interphase framework (3D-SEIF) inside LMAs. Spontaneous while mild chemical reactions between lithium metal and lithium bisfluorosulfonimide/lithium nitrate form the robust 3D-SEIF, mainly consisting of LiF, Li₃N, and LiN_xO_y. The built-in 3D-SEIF avoids electrolyte contact but enables the diffusion and reduction of Li⁺ ions in the bulk phase, thus isolating the plating sites and electrolyte contact interface. The 3D-SEIF facilitates large granular plating and the generation of thin, inorganic-rich SEI. When assembled with high-loading LiNi_0.6Co_0.2Mn_0.2O₂ cathode (3 mAh cm⁻²), the cells present capacity retention of 92.0% after 130 cycles with barren electrolyte (≈30 µL) at 0.5 C. The conception of 3D inner interphase allows breaking the coupling of interfacial reactions with electrochemical reactions, which is taken for granted in electrochemical consortium. It also desires to inspire new thoughts to develop scalable solutions for the early industrialization of LMBs.