水平孔化背光改善研究

Improvement to the deposition characteristics of electroless copper plating

金属化孔质量直接关系到印制电路板的质量及可靠性，而镀层空洞的多少对孔壁质量的影响很大。评价孔壁镀层空洞的方法为测试沉铜层背光。文章以流程分析法，通过试验找到了影响沉铜背光不良的根本原因。并对产生机理进行了理论分析：去钻污后，板件孔壁吸附的中和调整剂经过烘干时其分子结构被破坏，影响沉铜活化钯离子在孔壁的吸附，进而导致背光不良。最终，文章针对失效根因进行了改善。将沉铜背光等级由8．5-9级提升至9．5级以上，改善了沉铜加工品质。

The reliability of plated through holes effects the printed circuit boards, and the plating voids is very important to the quality of hole wall. This paper found the root cause of backlight defect by DOE and worked out effective improvement step, and finally improved the backlight level from 8.5 to 9.5. It also analyzed the failure mechanism. After desmear, the PTHs were cleaned by neutralizer, and the regulators in neutralizer were adsorbed on the hole wall for improving the adsorption of Pd2＋. In baking process, the molecular structure of regulators were destroyed, which influenced the adsorption of Pd2＋ on the hole wall, and finally caused defect plating.