Electronics Forum | Wed Apr 27 02:22:08 EDT 2005 | grantp
Hi, There are a number of things you can try. You are already using 1:1 hole to pad ratio, and that's good as you need the size. I would try an electroform stencil as that will have a smooth side of the aperture and help paste release. Don't use c
Electronics Forum | Fri Feb 20 13:55:32 EST 2004 | black5629
That will depend on so many factors: solder type / flux type sphericity of balls in paste stencil type (laser chem etch, electro form etc.) print paramaters I will tell you that it can be done.
Electronics Forum | Thu Sep 23 12:47:48 EDT 1999 | Earl Moon
| | | 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.
Electronics Forum | Wed Sep 22 21:23:03 EDT 1999 | se
| | 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
Electronics Forum | Thu May 09 10:00:19 EDT 2002 | brianockert
I'd tend to agree with what the others have said. Check the basics, board supports, setup, wiper paper working correctly. If it's a humidity issue, try taking some paste, place it on a chem wipe, and roll it around a bit, which removes some of the mo
Electronics Forum | Wed Jul 01 03:05:56 EDT 1998 | Jon Gruett
| WHAT SHOULD THE RATIO BE OF STENCIL APERATURE TO PAD TO GET GOOD QUALITY RESULTS. BY THAT I MEAN, A MINIMM OF SOLDER BALLS, AND LITTLE TO NO BRIDGING, SHORTS, ETC.. | RIGHT NOW WE ARE USING A 1:1 RATIO, BUT ARE INVESTIGATING REDUCING THE APERATU
Electronics Forum | Mon Jun 29 13:51:29 EDT 1998 | Russ Miculich
| WHAT SHOULD THE RATIO BE OF STENCIL APERATURE TO PAD TO GET GOOD QUALITY RESULTS. BY THAT I MEAN, A MINIMM OF SOLDER BALLS, AND LITTLE TO NO BRIDGING, SHORTS, ETC.. | RIGHT NOW WE ARE USING A 1:1 RATIO, BUT ARE INVESTIGATING REDUCING THE APERATU
Electronics Forum | Mon Jun 29 13:50:48 EDT 1998 | Russ Miculich
| WHAT SHOULD THE RATIO BE OF STENCIL APERATURE TO PAD TO GET GOOD QUALITY RESULTS. BY THAT I MEAN, A MINIMM OF SOLDER BALLS, AND LITTLE TO NO BRIDGING, SHORTS, ETC.. | RIGHT NOW WE ARE USING A 1:1 RATIO, BUT ARE INVESTIGATING REDUCING THE APERATU
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 | Thu Mar 05 23:52:26 EST 1998 | Ron Costa
| Hi Ron, | Your question really opens up a "Pandora's box", but when you say you're not able to print perfectly, what is it exactly that you mean? Is the print lacking volume? Is it mis-registered? Are you bridging? Also, what printers have you used
