How to deal with PCB surface discoloration?

- Nov 17, 2018-

Q: the discoloration of the gold surface is generally related to the gold plating solution of this process and the SOLDMASK of the previous process.As a former engineer of SOLDMASK, I think it may be that the plates are not clean during the process of development, which should be solved as long as the professional engineer of SOLDMASK is followed up.Otherwise, external pollution is produced in the production process, which is troublesome and requires the cooperation of influential people in different departments to effectively control pollution sources.

A. it's not a problem of SOLDERMASK itself, but a problem of process.The root cause of the discoloration of the gold surface here is that the liquid medicine enters the hole and cannot be cleaned, thus causing the gold surface pollution.Improving wet film processes and cleaning can help.

2. Gold discoloration is one of the most common problems, which is mainly solved from the following aspects:

1. Copper pollution of nickel tank

2. Electrical conductivity of ion water before plating

3. Metal pollution of gold trough

4. Pure gold concentration