共查询到20条相似文献,搜索用时 125 毫秒
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在无铅组装工艺中,大多数电路板组装厂优先采用低成本焊料合金。没有添加剂的锡铜无铅焊料本身存在局限性,可是添加某种成份后,就能克服锡铜焊料通常所遇到的不足之处。文章分析了几种锡铜焊料相对于SAC焊料的特点,并叙述了它们在波峰焊和手工焊接工艺中的应用情况。 相似文献
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电子封装与组装是电子产业的重要支柱之一,而今绿色制造己成为普世的价值和标准。在绿色电子封装与组装产业中,无铅焊与其相关可靠性占有着最关键的地位。对于无铅焊接的实行,材料选择主要是含有Sn的焊料。当前,Sn-Ag-Cu(SAC)合金被认为是无铅标准合金中最多使用的系列之一。然而,各地区之间对无铅焊料的选择仍存在诸多分歧,不同公司会选择不同配比的SAC焊料系列。 相似文献
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传统含银无铅焊料已经被证明是最有潜力替代Sn-Pb合金的焊料并被广泛应用.可观的Ag含量也意味着焊料成本增加.因此,低银合金的研发开始受到科研机构和工业界广泛关注.但是低银产品的服役性能都低于主流的SAC系合金.采用引入微量元素Ce的方法提高接头可靠性.结果表明,Ce元素的添加提高了钎料的可焊性、抗拉强度以及热循环下的服役性能.此外,稀土元素的添加并未引发Sn晶须的生长. 相似文献
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无铅焊料的选择与对策 总被引:4,自引:1,他引:3
通过大量的数据信息分析了各研究机构在无铅焊料方面的研究成果,在目前流行使用的无铅焊料的基础上,进一步研究并比较了其中的Sn-Cu系列与具有专利限制的SnAgCu系列焊料在消费类电子产品组装的波峰焊工艺中使用的可靠性,同时研究并比较Sn-Ag系列焊料与SnAgCu系列焊料在回流焊工艺使用的情况.结果表明,Sn-Cu共晶焊料在消费类电子产品组装的波峰焊工艺中完全可以取代Sn-Ag-Cu系列焊料,同时满足使用要求;而同样技术成熟的Sn-Ag共晶焊料也完全可以取代SnAgCu系列焊料在回流焊工艺使用,焊点的可靠性与成本可以媲美SnAgCu焊料,而且该二元合金在使用维护以及回收利用方面具有相当的优势. 相似文献
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电子组装材料的润湿性对于形成良好的焊点质量至关重要,实际生产中要求对组装材料进行润湿性评估。采用润湿平衡测试法对氮气保护下的焊料及焊膏润湿性进行了测试,并阐述了此方法的工作原理、测试过程、评估标准及适用范围,为电子组装材料技术性采购提供了一种评估润湿性的有效方法。 相似文献
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Solder paste is the strategic material for the electronic card assembly process, based on the surface mounting technology.
The paste is a concentrated suspension (50% of volume) of metallic powder in an organic continuous phase and its screening
on the printed circuit board is the first operation of the assembly. The result of the screening depends strongly on the rheological
characteristics of the solder paste but, nevertheless the research activity on this material is so far very poor. In this
paper, an analytical procedure for the rheological characterization is given and the most important rheological parameters,
affecting the screening performance, are shown. 相似文献
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Bo Wang Jiajun Li Anthony Gallagher James Wrezel Pongpinit Towashirporn Naiqin Zhao 《Microelectronics Reliability》2012,52(7):1475-1482
The poor drop-shock resistance of near-eutectic Sn–Ag–Cu (SAC) solder interconnects drives the research and application low-Ag SAC solder alloys, especially for Sn–1.0Ag–0.5Cu (SAC105). In this work, by dynamic four-point bend testing, we investigate the drop impact reliability of SAC105 alloy ball grid array (BGA) interconnects with two different surface mounting methods: near-eutectic solder paste printing and flux dipping. The results indicate that the flux dipping method improves the interconnects failure strain by 44.7% over paste printing. Further mechanism studies show the fine interfacial intermetallic compounds (IMCs) at the printed circuit board side and a reduced Ag content inside solder bulk are the main beneficial factors overcoming other negative factors. The flux dipping SAC105 BGA solder joints possess fine Cu6Sn5 IMCs at the interface of solder/Cu pads, which increases the bonding strength between the solder/IMCs and the fracture resistance of the IMC grains themselves. Short soldering time of flux dipping joints above the solder alloy liquidus mitigates the growth of interfacial IMCs in size. In addition, a reduced Ag content in flux dipping joint bulk causes a low hardness and high compliance, thus increasing fracture resistance under higher-strain rate conditions. 相似文献
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当今元件封装技术正日新月异,以满足不断快速增长的电子产品的需求。0201/01005是现代电子组装技术的新概念,它能大幅度降低电子产品体积。0201/01005封装由于元件尺寸小,有许多专门的装配注意事项。文章从线路板设计、焊膏选择、贴装控制等几个方面浅谈0201/01005元件装配工艺技术。 相似文献
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No-clean fluxes allow simplifications in the surface mount technology process, but introduce reliability problems for electronic
assemblies during their service life. An electrochemical method is devised to study the anodic reactivity of Sn, Pb, eutectic
Sn-Pb solder alloy and Cu in aqueous solutions containing no-clean paste residues obtained during a reflow process. The potential
corrosion risk of residues from two different pastes is evaluated, and the corrosion behavior of the different metals assessed.
Cu corrodes faster than Sn, Pb, and the solder alloy in presence of the residues, but corrosion starts at higher overvoltages.
Pb corrodes at low overvoltage; Sn is prone to oxidation and passivation. The solder alloy has an intermediate behavior between
those of the pure metals. 相似文献
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当今组件封装技术正日新月异,以满足不断快速增长的电子产品的需求。0201/01005是现代电子组装技术的新概念,它能大幅度降低电子产品体积。0201/01005封装由于组件尺寸小,有许多专门的装配注意事项。本文从线路板设计、焊膏选择、贴装控制等几个方面浅谈0201/01005组件装配工艺技术。 相似文献
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Ho S.L. Xie M. Tang L.C. Xu K. Goh T.N. 《Electronics Packaging Manufacturing, IEEE Transactions on》2001,24(4):323-332
The formation of reliable solder joints in electronic assemblies is a critical issue in surface mount manufacturing. Stringent control is placed on the solder paste deposition process to minimize soldering defects and achieve high assembly yield. Time series process modeling of the solder paste quality characteristics using neural networks (NN) is a promising approach that complements traditional control charting schemes deployed on-line. We present the study of building a multilayer feedforward neural network for monitoring the solder paste deposition process performance. Modeling via neural networks provides not only useful insights in the process dynamics, it also allows forecasts of future process behavior to be made. Data measurements collected on ball grid array (BGA) and quad flat pack (QFP) packages are used to illustrate the NN technique and the forecast accuracies of the models are summarized. Furthermore, in order to quantify the errors associated with the forecasted point estimates, asymptotically valid prediction intervals are computed using nonlinear regression. Simulation results showed that the prediction intervals constructed give reasonably satisfactory coverage percentages as compared to the nominal confidence levels. Process control using NN with confidence bounds provides more quality information on the performance of the deposition process for better decision making and continuous improvement 相似文献