Electronics Forum | Tue Jan 22 22:23:48 EST 2008 | amarpreet41
Thanks, I am working on to prevent solder bridging. Tried fine tuning reflow profile, solder printing looks fine. Any further ideas??
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 | 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 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 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 | 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 | 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
Electronics Forum | Thu Sep 12 10:45:29 EDT 2002 | pbarton
We have used a laser cut stencil 0.15mm (0.006") thick with 0.3mm (0.012") square apertures radiused in the corners 0.06mm (0.0025") to aid paste release. This approach with the (type 3) paste we use has proven successful on thousands of devices plac
Electronics Forum | Wed Jul 15 12:31:20 EDT 2009 | rwyman
Depending on the end use of the PCB, edge or corner bonding may be adequate. Much easier to rework as the material is only at the perimeter of the part. We don't do underfill of any degree in-house but a few years ago we did build a limited run of
Electronics Forum | Mon Jun 13 01:38:59 EDT 2011 | kenneth0
Hello Steve, i think you are experiencing the potato chip effect, where temperature difference at the center and edges are huge; causing BGA edges to tilt down or up.Try narrow down the temperature difference between the center of BGA and corner. I
