基体表面性质对引线框架上无铅镀锡层的影响

摘要

The effects of Cu substrate surface on tin deposits of Pb-free electroplated lead frames were examined. The SEM and XRD data show that the appearance of deposits depends on crystal structure. The XPS results indicate that the surface oxidation state of Cu lead frame has a great impact on the appearance of tin deposits. The tin deposits electroplated on Cu lead frame with CuO surface layer tend to exhibit black surface appearance. The deposits quality can be improved by strengthening descaling process before plating or increasing electrochemical polarization of the additive in the bath.%研究了铜基引线框架基体表面性质对镀锡层的影响.扫描电镜(SEM)和X射线衍射(XRD)分析结果表明:镀层外观由其结晶结构决定.采用X射线光电子能谱(XPS)研究了铜基引线框架表面性质的影响.结果表明:引线框架表面铜的氧化状态对于最终所得镀锡层的性质有很大影响,当引线框架表面存在大量的CuO时,得到的镀锡层易于出现发黑等质量缺陷.研完了相应的解决方法,对于因基体表面性质引起的镀层发黑等质量问题,可以通过加强镀前去氧化解决,也可以通过增强添加剂的极化作用予以改善.