Electronics Forum | Fri Nov 08 08:52:54 EST 2002 | dphilbrick
Juan There are many things that cause this and the first thing I would do is request quality records from your board fab facility on that particular lot. If they are unwilling to give them to you this is a good sign they had a processing problem. Th
Electronics Forum | Wed May 11 13:50:30 EDT 2005 | russ
I would contact your paste supplier, bare nickel can be impossible to wet to. How oxidized is it?
Electronics Forum | Thu May 05 16:02:43 EDT 2005 | russ
I don't believe that you are seeing black pad. I think you are seeing an oxidized pad from your statement that these pads take solder. I would guess that these will be fine. But I would re-tin all pads prior to attaching the BGA to make sure.
Electronics Forum | Fri Feb 20 13:01:26 EST 2004 | Jay
First, it depends on the alloy composition of the solder. As you might know, eutectic Sn/Pb solder has the lowest melting point among available conventional solder systems. (except those based on Sn-In and Sn-Bi systems.) For example, 63Sn/37Pb - 183
Electronics Forum | Thu May 05 17:15:46 EDT 2005 | russ
You got what I think someone has called a "cold melt". If you were to run your removal profile awhile longer you would not see this. Anyway, you don't have any issues as this is very common (at least in my experience). FYI I was thinking your oxid
Electronics Forum | Thu May 05 09:17:58 EDT 2005 | jimmiem
I tried soldering to several of the black pads and was successful, the solder stuck with no hesitation. so i guess this is not truly "black pad"? would that be a correct statement? What causes this blackening that looks like oxidation under the mic
Electronics Forum | Thu Aug 21 22:10:07 EDT 2003 | adlsmt
Well, for some reason the board house will pay for the boards but has some issue with paying for the parts on them. Why am I not supprised? Perhaps I have mis-diagnosed the problem. We have found two different board p/n's with the same type of defec
Electronics Forum | Mon May 17 13:21:45 EDT 2021 | SMTA-64387881
PWB Bake out or other elevated temperture processes can cause issues with oxidation of that Nickel layer. The gold porosity can vary from batch to batch, but also process changes can contribute. Are you baking the boards or have previous reflow pro
Electronics Forum | Mon Apr 26 17:09:05 EDT 2021 | kwalker
Sounds like you are getting oxidation of the nickel under the gold layer. If the gold is porous it will allow the nickel underneath to oxidize, which is the dark dull layer you are seeing, and why when you apply flux it solders just fine - the flux i
Electronics Forum | Tue Apr 27 21:24:14 EDT 2021 | kwalker
No, you're correct. Nickel oxidation can be difficult to remove
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