Electronics Forum | Fri Aug 16 10:00:03 EDT 2002 | davef
You have a very bad situation. It�s tough for the gas, flux material, er whatever to escape when the BGA is sitting on top of it and the blind via is blocking it from the other side. Obviously the vias should have been: * Placed on the edge of the
Electronics Forum | Tue Sep 17 15:03:31 EDT 2002 | davef
Contact: * PCD Magazine [ http://www.pcdmag.com/mag/reprints.html ] and ask them to send you a reprint. * Jim Blankenhorn [ http://www.smtplus.com ] and ask him to send you a reprint. Or try: * �Assembly And Interconnect Reliability Of BGA Assembled
Electronics Forum | Wed Mar 14 13:16:54 EDT 2007 | Shane
I have a customer that designed a fine pitch BGA into a board, and has put small vias in the middle of each pad on the PCB. Anyone have any ideas on how I can prevent the solder from the BGA from flowing through the vias and causing voids or no cont
Electronics Forum | Fri Mar 23 09:13:48 EDT 2007 | Peter W
Hello, those plated and solderable via in pads have two critical points: 1. We have discovered that _sometimes_ the plating seems not to be perfect, as extreme voiding is visible in tha bga solder ball 2. The detection of some defects by AXI is limi
Electronics Forum | Mon Feb 19 22:56:20 EST 2007 | davef
Russ We agree with your comments on plugging from one side only. But... We believe that it IS possible to trap process chemicals [technically, not flux] in a blind [or any other] via. This can be done by plating the via closed, rather than pluggi
Electronics Forum | Fri May 02 09:37:23 EDT 2003 | Jerry Magera
Via in pad is the most efficient use of space. Blind via seems to be blamed for this. Cross-sections (send me some) will probably show a void still existing in the via or spherical voids aligned near the component pad side. One can estimate the vo
Electronics Forum | Wed Nov 21 21:50:50 EST 2001 | Glenn Robertson
Tony, What you are seeing can occasionally be caused by gaps in the plating of the blind vias. If they are not "airtight" you can get moisture coming from the laminate that shows up as voids in the solder balls. You might check on the board sup
Electronics Forum | Tue Nov 20 12:48:40 EST 2001 | tony_sauve
We recently experienced a problem w/voids (up to 65%) in uBGA solder joints. The only joints that have the problem correlated to pads which had blind 0.006" via's in them. The via's only extend down 2 layers, of the 18. 21 BGA's on the PCB, only expe
Electronics Forum | Mon May 05 11:48:33 EDT 2003 | mk
We have had good luck with via in pads using solid solder deposition. Please contact me off line or provide a number I can call. Thanks Matt Kehoe m.j.kehoe@att.net
Electronics Forum | Thu Nov 22 12:56:12 EST 2001 | tony_sauve
Thanks for the comments & suggestions. Here's some info garnered from a telecon w/the PCB Fab house: -the blind via's extend from layer 2-17...this was a revelation. The info from our customer was that the via's only extended down 2 layers. Did I men
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