干膜与阻焊油墨对化镍金厚度的影响

Influence of solder mask and dry film on thickness of ENIG

感光阻焊与干膜析出物,是化镍金表面工艺金、镍缸控制寿命的原因之一,旨在改善黑焊盘缺陷。由于阻焊、干膜种类繁多,且阻焊、干膜与化镍金药水属于不同公司或厂家,鉴于配方专利等原因,单方对其相互影响原理甚至现象鲜有研究,此方面文献更是屈指可数。本文简述了"黑焊盘"发生的基本原理,并利用干膜以及不同阻焊油墨进行试验,通过测量镍金层厚度评估干膜与油墨对化镍金工艺的影响。通过机理验证试验,验证阻焊油墨析出物抑制化镍反应,而非目前业界所认知的加速反应。本实验一则为PCB厂家提供经验数据,利于生产控制;二则抛砖引玉,促进阻焊油墨、干膜、化镍金药水及PCB厂家对其进一步研究。

The leaching material out of solder mask and dry film is one of factors which influence the MTO of ENIG(Electroless Nickel Immersion Gold)’s Au and Ni tank. In order to improve the defect of black pad, it’s necessary to control the MTO. There are lots of corporations or factories producing and having research on various mask, dry film and ENIG materials. However, there’s little research and phenomena description about influence among solder mask, dry film and ENIG and fewer articles about this, because they are patented and belonged to different corporations or factories. This paper has a brief account of 'black pad', and the experiment is used dry film and different kinds of solder masks to evaluate their influences to ENIG finish through measuring the Au/Ni thickness. The mechanism validating experiment qualified confirmed that the leaching of solder mask can inhibit the electroless nickel reaction while it was considered as promoting reaction. It can not only provide the experiential datas for PCB plans to control fabrication more steadily, but also, using the little to get the big, promote solder mask, dry film, ENIG and PCB factories to give more research on the influence among them.