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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