Electronics Forum | Wed Dec 06 21:59:37 EST 2006 | SMTrework
Hello, we rework BGA packages that come back from the field. I've seen on occasion a black and or red "epoxy" substance from the manufacturer on the corner of some board's BGA chips that I imagine are applied to increase corner bond of the chip to th
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 | 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 | 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 | Wed Sep 11 16:57:04 EDT 2002 | bigwop
I've seen this problem caused by the cool down. > On a 7 zone oven I made a profile to peak at zone > 5 to give some semblance of control to the cool > down. The component can develope a big delta T, > because of the difference of materials Che
Electronics Forum | Tue Sep 07 22:15:26 EDT 1999 | NAZEEH CHAUDRY
| | | I have a zevatech 570 and 560 my boss want to place bga.s with these machines, Ive told him he needs to ugrade to newer machines. Zevatech say "no problem our machine are number 1". | | | these machines dont even offer bga selections. These mac
Electronics Forum | Wed Dec 06 22:35:05 EST 2006 | davef
Questions are: * When you say, "corner of some board's BGA chips", is it on the top of the package or between the board and the bottom of the package? * If between the board and the bottom of the package, does it span the distance between the board a
Electronics Forum | Wed Jan 16 22:57:52 EST 2008 | amarpreet41
Any one got experience on handling solder bridging under one corner of BGA?
Electronics Forum | Wed Jan 23 18:15:33 EST 2008 | gsala
Hi, are you dealing with Leaded or Lead Free P-BGA ? soldering by Lead or Lead Free paste ? Any way, some time, bridges can be caused by moisture entrapped in the BGA body. Make sure if is respected the correct MSL's allowed flore exposure time, ot
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????
