Summary for gold over silver Discussion
Gold over silver vs ENIG is discussed as an alternative PCB finish, with Jerome Marange asking about the pros, cons, and any corrosion or delamination risk. David replies that gold over silver may avoid some common ENIG problems, including black pad (black nickel), nickel skip plating, and the high temperature and long plating time of electroless nickel that can contribute to soldermask blistering. He also notes that ENIG is not ideal for gold wire bonding, while gold over silver may be better for that use. On the downside, David says the running cost of gold over silver may be higher than gold over nickel. The thread does not give a definitive corrosion or delamination verdict, so the practical takeaway is that the choice depends on the application and cost tradeoffs.
Q. Our local PWB manufacturer is using a gold over silver process instead of the ENIG.
My understanding is they use sterling silver instead of nickel as barrier between the gold and the copper. But I could not find more on the net.
What are the pros and cons of gold over silver process?
Are there any risk of corrosion or delamination (MLB) of the PWB with this process?
Thank you
Jerome Marange
– Auckland, New Zealand
August 14, 2012
A. Hi Jerome,
What I can think of is gold over silver instead of ENIG can avoid common ENIG defects such as black pad (black nickel), nickel skip plating, high temp and long plating time of electroless nickel causing soldermask blistering, etc. Also, ENIG is not good for gold wire bonding but gold over silver might be better.
However, running cost of gold over silver might be higher than gold over nickel.
Regards,
David
David Shiu
– Singapore
August 16, 2012