Electronics Forum | Wed Nov 10 18:02:54 EST 1999 | John Thorup
Hi Dave Sounds like what we call a "squeeze ball". Usually caused by excess paste squeezed over the mask between the pads of the component when placed. This sometimes escapes the pull of surface tension back to the fillet and escapes to the side, us
Electronics Forum | Tue Sep 25 13:01:48 EDT 2001 | Hussman
If the flux you are applying by brush is alcohol based, use some alcohol on a few failed PCBs and retest. It souldn't take a lot of flux to reflow the balls to a pad that's already covered with solder and flux from the first BGA - unless you are cle
Electronics Forum | Thu Dec 08 10:48:21 EST 2005 | JP
Thanks Russ. As I was writing the post, it crossed my mind that stencil thickness is probably incorrect. I did not question the thickness because it was something that has been discussed with our stencil fabrication shop. When we were ordering mini
Electronics Forum | Tue Aug 22 03:04:07 EDT 2006 | PP
Any help/suggestion is much appreciated I am doing lots of BGA Reworks from a small uBGA with a few balls to a large BGA with over 1500 balls. The reworks have been done on SRT 1100 Series Machine for many years. SRT 1100 Machine is good for the c
Electronics Forum | Thu Mar 01 19:27:48 EST 2007 | Wayne
Yes, I am currently using Viromet 347 at the moment for my SMT lines. 100-150, 35 sec 150-207, 40 sec 207-above, 80 sec peak temp: 225 deg C. It is compatible to SAC paste in term of solderability and wettability. But in term of mechanical property (
Electronics Forum | Wed Jul 16 18:21:20 EDT 2008 | emti
BGA Placement is not easy as we think, Mainly you have to make sure you don't have acceessive amount of paste, try to paste your board as it covers full ball, make sure it is not short before you place any part. If you placing the BGA by hand be car
Electronics Forum | Mon Apr 29 14:36:26 EDT 2013 | bandjwet
I am trying to determine who out there is reballing devices below 0.4mm in pitch. We have been reballing as small as a 4-balled 0.15mm 4 mil ball diameter area array devices using an adhesive-backed reballing preform. 1. For such small devices we h
Electronics Forum | Wed May 28 19:21:09 EDT 2014 | hegemon
Just from the look of things (a picture) I would first guess it is a contamination problem on the PWB. Check over all your handling practices. Make sure the PWBs are NEVER touched by bare hands. I would not rule out the Black Pad phenomena, but i
Electronics Forum | Sun Sep 07 13:33:50 EDT 2014 | horchak
Edri PCBA design and pad geometry is one of the critical factors for BGAs. Typically the pad size for collapsible balls is 80% of the ball diameter. Pad size consistency is critical. In your situation what will happen the larger pads will wick the s
Electronics Forum | Fri Dec 04 05:47:57 EST 2015 | rushpcbuk
In PCB design, a BGA (Ball Grid Array) package typically determines the number of layers that a Printed Circuit Board should have. However, the 4-layer board with a BGA package is commonly used than a 2-layer than an 8-layer PCB. On the other hand, t
