【摘要】 研究了化学镀镍层磷含量、粗糙度、杂质和镀镍后间隔时间,浸金液温度以及线路板上焊盘(PAD)对金层均匀性的影响。结果表明,引起浸金层不均匀的原因主要有:化学镀镍层各部位的磷含量和表面粗糙度存在差异,化学镀镍层中存在杂质,化学镀镍与浸金的间隔时间过长而使镍层被氧化,浸金槽内各处液温度分布不均,线路板上各处PAD大小有差异。这些因素引起的金层不均匀问题多数可通过严格规范相关操作加以解决。更多还原

【Abstract】 The effects of several factors including phosphorus content, roughness and impurity of electrolessly plated nickel coating, as well as the time interval after electroless nickel plating, temperature of immersion gold bath, and pad on printed circuit board on the uniformity of gold coating were studied. The results showed that the main causes leading to the nonuniformity of immersion gold coating are as follows: differences of phosphorus content and surface roughness at different parts of electroless nickel coating, existence of impurities in electroless nickel coating, oxidation of nickel coating for too long time interval between electroless nickel plating and immersion gold plating, uneven distribution of temperature in immersion gold plating tank, and difference of pad size at different parts of printed circuit board. All of the nonuniformity problem of gold coating caused by the above factors can be solved by strictly following the related practice standards.更多还原