Electronics Forum | Thu Nov 07 10:59:11 EST 2002 | pjc
IPC-7525 "Stencil Design Guidelines" is a good reference document to have. Here are notes from a Tessera, (a major mBGA mfg.), study- "Application Note Solder Stencil Requirement for mBGA" The stencil aperture is to be square, equal in size to the l
Electronics Forum | Fri Mar 12 11:53:47 EST 2004 | Dreamsniper
Thanks Dave...it's such a good site for reworking BGA's (reballing). But what about when it comes to re-attaching the BGA onto the PCB? We are using Flextac Stencils but I found out that the apertures of their stencil is bigger than our pads for the
Electronics Forum | Wed Jun 20 08:14:36 EDT 2007 | pavel_murtishev
Good afternoon, You should use overprint technique if you have any problems with paste volume (PIH technology and mixed designs, for instance). Otherwise, it is useless. Overprint has to be made in such way so that paste would have an ability to flo
Electronics Forum | Wed Jun 14 09:34:25 EDT 2017 | cyber_wolf
In my experience there is no need for wet wiping stencils. We run 0201'and micro BGA's daily with no issues. If you are having paste release issues, I would be looking at other things. Aperture area aspect ratio, aperture design, land design, sold
Electronics Forum | Mon Jul 12 13:27:35 EDT 1999 | Upinder Singh
Hi all , We are trying to implement the micro-BGA technology at our plant. I need the clarification to the following points: 1. Is underfill required for micro-BGAs? 2. What type of stencil apertures are the industry standards for uBGAs and of wha
Electronics Forum | Tue Jun 28 14:06:08 EDT 2011 | dmiller
If you have room, and the aperture size will allow for it, try a 5 mil overall stencil thickness with a 1 mil step-up in the area of the BGA connector.
Electronics Forum | Mon Mar 27 08:28:48 EST 2000 | Mark Alder
Dear Robert The reason for the bridging problem you are experiencing on your BGA's is due because of too much solder. The PCB pads need to be at least 15% larger than the sphere size of the BGA balls. If you are not using C4 (63/37) BGA spheres and
Electronics Forum | Thu Nov 03 10:49:11 EST 2005 | russ
This is what I would propose, Place and reflow the board without the BGA with your lead process, remove the solder from the BGA pads if you cannot mask off the apertures in your stencil. Then place the BGA and reflow to SAC requirements with a rewo
Electronics Forum | Tue Sep 21 12:10:23 EDT 1999 | Mario
| I've had some trouble pasting a test board for a MicroBGA trial. Most of the paste remains in the stencil apertures. | The stencil is 6 mil thick, laser cut and electo-polished. | The apertures are 12 mil in diameter with 20 mil pitch. | We are usi
Electronics Forum | Mon Sep 20 17:46:21 EDT 1999 | Dave F
| I've had some trouble pasting a test board for a MicroBGA trial. Most of the paste remains in the stencil apertures. | The stencil is 6 mil thick, laser cut and electo-polished. | The apertures are 12 mil in diameter with 20 mil pitch. | We are usi
