适用于IC封装的表面涂覆层——化学镀镍、钯、金的未来

概述了化学镀镍/化学镀钯/浸金涂（镀）覆层的优点,它比起化学镀镍/浸金,不仅更适用于IC封装,而且提高了可靠性,降低了成本。     

对发展IC封装载板用覆铜板的探讨[上]

本文对当前IC封装载板用覆铜板技术,特别是三菱瓦斯化学公司的BT树脂覆铜板制造技术的发展现状,及IC封装载板用基板材料市场格局的新变化进行了分析、探讨,以期对发展我国此方面覆铜板技术起到抛砖引玉的效果。     

令人瞩目的平板显示器印制板及IC封装载板

在今年三月份召开的CPCA2007年春季国际PCB技术/信息论坛上,Prismark的姜旭高博士发表了题为《全球PCB产业状况与发展趋势》的演讲。谈及未来PCB产业的发展机会时,他指出:全球PCB行业增速的放慢造就了中国的高成长,但未来能否再保持10%￣20%的增长对中国而言挑战很大,不过增长速度一定会超越全球。今后PCB行业的成长动力将主要来自以下几个方面:     

山东恒汇电子科技有限公司年产20亿片IC封装载板项目正式投产

2011年9月28日,山东恒汇电子科技有限公司年产20亿片IC封装载板项目在淄博举行了投产仪式。 IC封装载板是用于集成电路卡模块封装用的一种关键专用基础材料,     

高精度陶瓷基板化学镀多层膜技术研究

描述了针对高精度陶瓷基板采用化学镀的技术,对陶瓷基板线条进行金属化,达到多种膜层结构,以满足产品所需要的特殊厚度、电性能和金丝压焊的要求。研究了化学镀厚铜、离子钯活化、化学镀镍和化学镀厚金溶液的各项参数变化,以及参数变化对陶瓷基板线条厚度和精度的影响。并对实验结果进行分析,讨论各种现象出现的原因。     

Sn95Sb5焊料与ENIG/ENEPIG镀层焊点界面可靠性研究

研究了Sn95Sb5焊料在化学镍金(ENIG)镀层、化学镍钯浸金(ENEPIG)镀层表面形成的焊点界面微观组织形貌与剪切强度。使用Sn95Sb5焊料在FR4印制板上焊接0805片式电容,焊点在高温时效测试和温度循环过程中均表现出较高的剪切强度,焊点界面连续且完整,剪切强度下降的最大幅度不超过19.2%。Sn95Sb5焊料在ENIG镀层表面形成的焊点(Sn95Sb5/ENIG焊点)强度更高。Sn95Sb5焊料在ENEPIG镀层表面形成的焊点(Sn95Sb5/ENEPIG焊点)界面反应更为复杂,在焊点界面附近可观察到条块状的(Pd,Ni,Au) Sn₄。Sn95Sb5/ENEPIG焊点界面的金属间化合物层平均厚度约为Sn95Sb5/ENIG焊点界面的2倍。     

化学镀镍/化学镀钯/浸金表面涂覆层的再提出

文章概述了化学镀镍/化学镀钯/浸金表面涂(镀)覆层的特性.不仅它能够满足各种各样的类型元件和安装工艺的要求,而且也能满足高密度的IC基板封装的要求.因而,化学镀镍/化学镀钯/浸金表面镀层是一种"万能"的镀层,具有最广泛的应用前景.     

化学镀镍金层可焊性的影响因素

我们将国内外报道化学镀镍金的部分最新研究成果,同我们实验室的实践相结合,对造成化学镀镍金可焊性差的多种因素作一简要介绍。本文总结了影响化学镀镍金可焊性的复杂因素如:前处理的影响、化学镀镍过程的影响、浸金的影响、浸金后水洗的影响、焊料的影响。     

化学镀镍镀钯浸金表面处理工艺概述及发展前景分析

随着电子封装系统集成度逐渐升高及组装工艺多样化的发展趋势,适应无铅焊料的化学镀镍镀钯浸金（ENEPIG）表面处理工艺恰好能够满足封装基板上不同类型的元件和不同组装工艺的要求,因此ENEPIG正成为一种适用于IC封装基板和精细线路PCB的表面处理工艺。ENEPIG工艺具有增加布线密度、减小元件尺寸、装配及封装的可靠性高、成本较低等优点,近年来受到广泛关注。文章基于对化学镍钯金反应机理的简介,结合对镀层基本性能及可靠性方面的分析,综述了ENEPIG表面处理工艺的优势并探讨了其发展前景。     

选择性化学镍/金工艺的应用

本文主要通过对选择性化学镍／金的生产应用，就流程中的二次干膜、退膜、化学镍金、OSP的相关生产控制进行总结。     

镍层耐硝酸腐蚀性测试——一种简单的预先探测ENIG镍层“黑盘”现象的测试方法

随着更加精细的SMT、BGA等表面贴装技术的运用,化学沉镍金(ENIG)作为线路板最终表面处理得到了越来越广泛的应用,同时可怕的“黑盘”现象也随之更广泛地“流行”起来,直接导致贴装后元器件焊接点不规则接触不良。为了贯彻执行最好的流程控制和采取有效的预防措施,了解这种焊接失败的产生机理是非常重要的,及早的观测到可能发生“黑盘”现象的迹象变得同样关键。本文介绍了一种简单的预先探测ENIG镍层“黑盘”现象的测试方法-镍层耐硝酸腐蚀性测试,这种测试可以用于作为一种常规的测试方法监测一般化学沉镍溶液在有效使用寿命范围内新鲜沉积的镍层的质量。利用Weibull概率统计分析在不同的金属置换周期(MTO)下镍层的可靠性能表现。结合试验结果得出了一个镍层耐硝酸腐蚀性的判定标准。     

Origin of Surface Defects in PCB Final Finishes by the Electroless Nickel Immersion Gold Process

We suggest a unique mechanism for surface defect generation causing solder joint or bonding failures in printed circuit boards (PCBs). Surface defects can be defined as corroded holes or spikes of the Ni-P layers on the soldering or wire bonding pads of PCBs. The typical defects are the black pad or pinhole pad defects generated after final finishing by the electroless nickel immersion gold (ENIG) process. Once corroded voids or spikes are plentifully created in nickel/gold interfaces, the bonding strength of solder or wire bonding joints is reduced. Therefore, it is important to characterize the details of these surface defects. In this paper, the defect microstructures and the P content variation with the ENIG processes are investigated. The surface defect selectivity with pad size and pad connectivity is suggested based on the key findings of P content variation. An overall mechanism is proposed based on a mixed mode of concentration cell corrosion and galvanic cell corrosion. Based on these results, more reasonable root causes are suggested.     

对集成电路封装塑封料湿敏性评定技术的探讨

在有关塑封料的湿度浸入研究中,湿气或者是穿过聚合物渗透,或者是沿着引线与密封树脂之间的界面渗透。本文主要是通过试验对与湿度渗透有关的新一代树脂的特性给予评定,并判定引线框架通路是如何影响湿度浸入的。     

Effect of Gold on the Corrosion Behavior of an Electroless Nickel/Immersion Gold Surface Finish

The performance of surface finishes as a function of the pH of the utilized plating solution was evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests in 3.5 wt.% NaCl solution. In addition, the surface finishes were examined by x-ray diffraction (XRD), and the contact angle of the liquid/solid interface was recorded. NiP films on copper substrates with gold coatings exhibited their highest coating performance at pH 5. This was attributed to the films having the highest protective efficiency and charge transfer resistance, lowest porosity value, and highest contact angle among those examined as a result of the strongly preferred Au(111) orientation and the improved surface wettability.     

作为工艺控制函数的化学镀镍／浸金可焊性和焊接可靠性

在过去的十多年里,由化学镀含磷的镍厚为3.0～5.0μm(120～200μin)和浸金厚为0.05～0.10um(2.0～4.0μin)组成的涂覆层已经确定,它作为高可靠性,包括复杂的电路设计的应用的一种可焊性表面涂覆层。通常泛指为ENIG     

半导体晶圆ENIG/ENEPIG产品设计考量

通过化学自催化反应在半导体晶圆I/O铝或铜金属垫上沉积具有可焊接性的镍金/镍钯金层,此工艺已在MOSFET、IGBT、RFID、SAW Filter等产品上得到广泛应用。着重阐述了在新产品设计和工程评估阶段,对于晶圆产品本身应予以考量的因素,如钝化层种类及厚度,I/O金属垫的成分及结构,切割轨道上金属图形的大小及钝化层的覆盖,不同I/O pad的电势等。其中一些因素导致的问题会直接影响化学镍金/镍钯金后产品的性能应用。在化镀工艺过程中,要充分了解产品本身结构以及可能造成的相应缺陷及问题,并且应综合考虑这些因素的影响。     

CMOS影像感应器构装——湿式无电镀镍沉积技术之最佳化

无电镀镍金(ElectrolessNickel&ImmersionGold;简称ENIG)沉积可以选择性地沉积于铝垫,由于此技术不必使用高成本之光阻微影制程,也不需真空溅镀制程,它可以降低制造成本。然而在实际制造大量生产时,常常面临到化学镀液很难控制之问题。经由精密控制其化学镀液中之一些重要参数,例如温度、pH值、还原剂、镍及稳定剂浓度等,可以明显提高制程性能,以满足量产需求。     

Effect of Pd Thickness on the Interfacial Reaction and Shear Strength in Solder Joints Between Sn-3.0Ag-0.5Cu Solder and Electroless Nickel/Electroless Palladium/Immersion Gold (ENEPIG) Surface Finish

Intermetallic compound formation at the interface between Sn-3.0Ag-0.5Cu (SAC) solders and electroless nickel/electroless palladium/immersion gold (ENEPIG) surface finish and the mechanical strength of the solder joints were investigated at various Pd thicknesses (0 μm to 0.5 μm). The solder joints were fabricated on the ENEPIG surface finish with SAC solder via reflow soldering under various conditions. The (Cu,Ni)₆Sn₅ phase formed at the SAC/ENEPIG interface after reflow in all samples. When samples were reflowed at 260°C for 5 s, only (Cu,Ni)₆Sn₅ was observed at the solder interfaces in samples with Pd thicknesses of 0.05 μm or less. However, the (Pd,Ni)Sn₄ phase formed on (Cu,Ni)₆Sn₅ when the Pd thickness increased to 0.1 μm or greater. A thick and continuous (Pd,Ni)Sn₄ layer formed over the (Cu,Ni)₆Sn₅ layer, especially when the Pd thickness was 0.3 μm or greater. High-speed ball shear test results showed that the interfacial strengths of the SAC/ENEPIG solder joints decreased under high strain rate due to weak interfacial fracture between (Pd,Ni)Sn₄ and (Cu,Ni)₆Sn₅ interfaces when the Pd thickness was greater than 0.3 μm. In the samples reflowed at 260°C for 20 s, only (Cu,Ni)₆Sn₅ formed at the solder interfaces and the (Pd,Ni)Sn₄ phase was not observed in the solder interfaces, regardless of Pd thickness. The shear strength of the SAC/ENIG solder joints was the lowest of the joints, and the mechanical strength of the SAC/ENEPIG solder joints was enhanced as the Pd thickness increased to 0.1 μm and maintained a nearly constant value when the Pd thickness was greater than 0.1 μm. No adverse effect on the shear strength values was observed due to the interfacial fracture between (Pd,Ni)Sn₄ and (Cu,Ni)₆Sn₅ since the (Pd,Ni)Sn₄ phase was already separated from the (Cu,Ni)₆Sn₅ interface. These results indicate that the interfacial microstructures and mechanical strength of solder joints strongly depend on the Pd thickness and reflow conditions.