Hi Paymon,

The E-Ni is thin indeed and it might be causing Cu diffusion (migration)
through it into Au. AS far as Cu corrosion you mentioned about is
concerned, then it may be not corrosion whatsoever. I think I know what
it is (and even may know where the board came from), but I'd need to see
the image. If that is what I think it is, then it's normal.

Vladimir

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Paymon Sani
Sent: Tuesday, February 12, 2008 2:30 PM
To: [log in to unmask]
Subject: [TN] Through Hole Pad Solder Non-Wetting

Hello All,

 

We experienced solder non-wetting to a PCB through-hole component pad
surface. The PCB surface finish is ENIG. The microsection results from
the suspect PCBs show that the Nickel plating is thin from 1 to 3
micro-inches. We related the thin Nickel plating to Nickel corrosion and
PCB surface non-wetting. However, the microsection also revealed copper
corrosion at Copper to Nickel interface! I have never seen the copper
corrosion in the past and I would like to ask if any of you has a
similar experience in the past. What could be the cause of copper
corrosion? I have few images if you are interested to see them.

 

Regards,

Paymon


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