SBIR Phase I: Ultra-Fine Solder Powder For Electronic Soldering

这个小企业创新研究第一阶段项目将展示用于电子锡膏的超细（1-10微米）锡粉表面氧化限制的可行性。今天，使用超细粉末来提高印刷线路板（pwb）上的粘贴印刷分辨率受到粉末巨大表面积上过量氧化负荷的阻碍。如果能够消除这一障碍，并且超细粉末商业化供应，不仅可以将PWB组件的密度增加10倍或更多，而且还可以创新焊膏印刷的新形式，例如按需滴注。在这个项目中，氧化物控制将通过两种方法进行演示：1)在粉末生产设备中应用氧屏障涂层；2)添加微量的合金金属来保护粉末表面。将采用能够在纳米级上分析焊料球上氧化层的分析方法。超细粉末将由NSF/SBIR第二阶段授予的现有工艺生产。这个项目的商业应用是在印刷线路板的制造。用于pcb表面贴装元件的焊膏的全球销售额超过5亿美元/年。大部分的浆糊是通过模版/刮刀印刷应用的。这一过程每年浪费约30%的浆糊，约合1.5亿美元。该项目的一个目标是通过更高分辨率的打印来减少浪费。然而，除非超细焊锡粉以具有竞争力的价格（约0.05美元/克）提供，否则无法实现这一目标。当组件变得更小（例如，倒装芯片）时，数量由粘贴打印分辨率控制，而不是由组件尺寸控制。这些结果的财政影响应该是相当大的。

This Small Business Innovation Research Phase I project will demonstrate the feasibility of limiting surface oxidation of ultra-fine (1-10 micron) solder powder for electronic solder paste. Today, the use of ultra-fine powder for increased resolution of paste printing on printed wiring boards (PWBs) is impeded by the excessive oxide burden on the powder's huge surface area. If this impediment could be removed, and ultra-fine powders were supplied commercially, not only could PWB component population density increase by 10 times or more, but new forms of solder-paste printing, such as Drop-on-Demand, could be innovated. In this project, oxide control will be demonstrated with two approaches: 1) oxygen-barrier coatings applied in the powder-production apparatus and 2) addition of trace amounts of alloying metals which can protect the powder surface. Assay methods that can profile, in nanometer steps, the oxide layer on the solder spheres, will be employed. The ultra-fine powder will be produced by an existing process developed under an NSF/SBIR Phase II award.The commercial application of this project is in the manufacture of printed wiring boards. The world sales of solder paste for surface-mounted components on PWBs is more than $500million/year. Most of the paste is applied by stencil/squeegee printing. That process wastes about 30% of the paste or about $150 million per year. One objective of this project is to reduce waste by higher resolution printing. However, that cannot be achieved unless ultra-fine solder powder is available at a competitive price (about $0.05/g). As components become smaller (e.g., flip chips), the population is controlled by paste-printing resolution, not by component size. Financial implications of these outcomes should be sizeable.