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A Complete Offering of Surface Finishes: From OSP to Immersion Silver

机译：完整的表面处理产品：从OSP到浸银

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The plating and surface finishing contract manufacturer Markus Hofstetter (Switzerland) is investing in modern processing equipment. Copper can tarnish under normal ambient conditions relatively quickly. To preserve solderability and avoid corrosion over extended periods of time, all exposed copper features on a PWB are protected by a surface finish. The importance of surface finishes will increase in coming years. The cosmetic appearance of the finish has some relevance but, more importantly, it determines solderability. This issue will become more critical in view of the conversion to no-lead solders by mid-2006. The days are long gone when HASL (hot air solder leveling) was an acceptable finish for all conceivable applications. For example, the inevitable finish thickness variations of HASL render this technology unsuitable for fine-pitch surface mount assembly. Wet chemical surface finish processes such as ENIG (electroless nickel, immersion gold) or immersion tin yield thinner, more uniform finishes. In addition, wet chemical processes don't involve extreme temperature excursions and are therefore preferred with thin circuit boards that are more susceptible to temperature induced stress and to twist and warp.
机译：电镀和表面处理合同制造商Markus Hofstetter（瑞士）正在投资购买现代加工设备。铜会在正常的环境条件下相对较快地失去光泽。为了保持可焊性并避免长时间腐蚀，PWB上所有裸露的铜特征均受到表面处理的保护。未来几年，表面处理的重要性将会提高。饰面的外观与外观有关，但更重要的是，它决定了可焊性。鉴于到2006年中期转换为无铅焊料，这一问题将变得更加关键。对于所有可能的应用，HASL（热风焊料调平）是可以接受的表面处理的日子已经过去了。例如，HASL不可避免的精加工厚度变化使该技术不适用于细间距表面安装组件。诸如ENIG（化学镍，浸金）或浸锡的湿化学表面处理工艺可产生更薄，更均匀的表面处理。此外，湿化学工艺不涉及极端的温度漂移，因此对于更容易受温度引起的应力以及扭曲和翘曲的薄电路板而言，湿化学工艺是首选。

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