树脂塞孔油墨扩散入孔问题研究

Study on diffusion of ink into resin plug hole

印制电路板(PCB)树脂塞孔工艺被普遍应用,孔密度也在不断提升。从实际应用案例出发,针对树脂塞孔产品后制程发生的不塞孔蚀刻后孔壁残铜问题进行研究分析,找出树脂塞孔过程中树脂扩散原因。研究发现,树脂扩散入孔主要发生在树脂塞孔完成后的烘烤过程中,蚀刻后孔内壁残留的油墨成分无法通过磨刷去除,呈现出不塞孔内壁残铜的不良现象。通过改变塞孔前处理来阻止树脂扩散,在塞孔研磨后,增加不同的清洁方式对PCB进行清洁处理。最终采用高锰酸钾浸泡清洁方案,该方案最具经济性且可量化生产。

Resin plugging technology is widely used for printed circuit board(PCB),and the hole density is also increasing.Based on practical application cases,the problem of residual copper in the hole wall after etching without plugging holes in the post-process of resin plug products is studied and analyzed,and the reason of resin diffusion in the process of resin plug holes is found.It is verified that the resin diffusion into the hole mainly occurs in the baking process after the resin plug is completed.After etching,the residual ink components on the inner wall of the hole cannot be removed by grinding brush,showing the bad phenomenon of residual copper on the inner wall without plugging holes.By changing the pretreatment of plug hole to prevent the resin from spreading,and using different cleaning methods to clean PCB after grinding plug hole,it is found that the most economical solution is to soak and clean PCB with potassium permanganate.