Assuming it’s not ENIG???

If not ENIG I would suspect immersion tin where the intermetallic has come to the surface.

If an ENIG problem or an immersion Tin problem it is not realistically recoverable without impacting the assembly with some serious reliability issues.

Sent from my iPhone

> On Dec 21, 2017, at 11:39 AM, Steve Gregory <[log in to unmask]> wrote:
> 
> Hi all,
> 
> I've been asked to post this to the Technet by a dear friend:
> 
> *We installed this little processor. At test we identified opens on the
> device. When we removed it we saw a number of pads that were matte gray
> with no evidence of solder adhered to the pad. *
> *We attempted to bump the pads with solder, they did not wet easily. In
> some cases we had to scrape through the matte finish to a shiny metal.
> But, we did get all the pads to appear wetted.*
> 
> *We cleaned the site well and then fluxed the bumps with a tacky flux ROLO
> designed for POP, placed the BGA and reflowed it on a rework station.*
> 
> *The assembly failed test with similar result, opens under the processor.*
> 
> *The attached photo shows that the bump process only appeared to wet the
> pads. The condition returned when we removed the BGA  second time.*
> 
> * http://stevezeva.homestead.com/2017-12-21_11.21.17.jpg
> <http://stevezeva.homestead.com/2017-12-21_11.21.17.jpg>*
> 
> *Have you seen this before? Is there any recovery? This assembly is worth
> about $45K. *
> 
> Thanks,
> 
> Steve
> 
> -- 
> Steve Gregory
> Kimco Design and Manufacturing
> Process Engineer
> (208) 322-0500 Ext. -3133
> 
> -- 
> 
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