Electronics Forum | Thu Dec 07 12:18:28 EST 2006 | realchunks
It may be for a double sided reflow process. Yes, some people do put the BGA on first. I know this first hand.
Electronics Forum | Thu Dec 07 14:17:03 EST 2006 | russ
I would bet that it is a SMT adhesive used to ensure that the BGA does not move during a secoindary reflow prcess. this glue is easily removed with a soldering iron. Russ
Electronics Forum | Wed Jun 25 11:06:35 EDT 2003 | James
Does anyone else have the same problem with BGAs that have a gold corner. It looks like the area where the gold corner is, it does not want to reflow proberly but the rest of the BGA reflows fine. Any suggestions????
Electronics Forum | Wed Jan 23 19:44:45 EST 2008 | hegemon
In addition to the pre-emptive steps mentioned above, in my experience there are certain BGA package designs that seem more prone to that corner bridging. I have seen some packages that will essentially "curl" down at one corner as the package begin
Electronics Forum | Thu Dec 07 03:21:54 EST 2006 | Guest
Materials you see are corner bond adhesive, main purpose of this is mechanical shock absorber , it promotes additional adhession to lessen stress to solder joints incase device subjected to mechanical stress like dropping.By function, corner bond
Electronics Forum | Wed Jun 25 12:08:53 EDT 2003 | russ
I battle this all the time, I don't believe that it is the "gold corner" that is causing the problem but something with the PCB layer makeup (copper planes, or bottom side components, etc.). It could also be the nozzle you are using has a "hot spot/
Electronics Forum | Wed Dec 06 22:46:39 EST 2006 | SMTrework
Hi Dave, This is manufacturer applied epoxy / adhesive to minimize package "lifing" from chassis flexing and thius board flexing. I have seen the complete array area covered with this black or red epoxy in some cases (i.e. the underfill that I've
Electronics Forum | Thu Jan 17 11:49:54 EST 2008 | wayne123
HI, I have ran into this a time or two, and what I did before we got the BGA rework station was to run some flux under the component, and since the flux that was in the solder on the other solder joints has at least part of the way burned off in the
Electronics Forum | Thu Dec 07 19:54:55 EST 2006 | davef
We agree with "guest" above. This a "chip bonder" type material used to improve the reliability of array type devices. "A relative comparison of the N50 values is given below: No underfill = 1.0X (baseline) Corner bond = 1.3X Non reworkable underfi
Electronics Forum | Tue Jul 13 00:40:44 EDT 2004 | Darren
Yes of course we are doing placement of BGA's with an IPII. However there is no front lighting so you can not inspect the balls. If the silhouette is square enough there is no problem with alignment. Just use the largest nozzle that will fit on the p
