Hi Steve - do you know what original board finish was used? ENIG? ImAg? ImSn? Dave Hillman Rockwell Collins [log in to unmask] On Thu, Dec 21, 2017 at 1:39 PM, 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 > > -- > > > This email and any attachments are only for use by the intended > recipient(s) and may contain legally privileged, confidential, proprietary > or otherwise private information. Any unauthorized use, reproduction, > dissemination, distribution or other disclosure of the contents of this > e-mail or its attachments is strictly prohibited. If you have received this > email in error, please notify the sender immediately and delete the > original. >