Electronics Forum | Thu Dec 15 11:06:05 EST 2005 | Samir Nagaheenanajar
You might wanna try a small reduction in your stencil aperture. For example, for a 30-mil pad go 26-mil square aperture with 8 to 10-mil radius on your corners. Also, look at your designs. Is there enough resist between your pad and ball? Another
Electronics Forum | Wed Jun 16 07:35:28 EDT 2010 | scottp
Rather than tent the thermal vias, we use a small annular ring of soldermask around them and only print paste in the areas between the vias. Any way you go you're going to have voids under QFNs, so we just try to make it repeatable so our designers
Electronics Forum | Mon Sep 28 19:07:47 EDT 1998 | Steve Gregory
| I have had some field failures returned recently, the boards had flux contamination under the components in a sensitive area, Nothing really visible until the component was removed, and the board had no evidence of rework of any type. Is it poss
Electronics Forum | Mon Oct 21 19:17:23 EDT 2013 | hegemon
The first picture shows an issue. Note that the vias adjacent to the interior rows are filled with solder. At the outside rows this is not evident. What you might have are interior spheres that are smaller in volume than the rows on the outide, si
Electronics Forum | Thu Mar 29 15:50:35 EST 2001 | tomgervascio
We've think that with seen solder shorts under BGAs after wave soldering the boards. In addition, it seems to be related to a certain soldermask configuration over the topside BGA vias.. THere is one vendor,A, that is applying soldermask after HASL,
Electronics Forum | Thu May 18 15:47:18 EDT 2006 | slthomas
Don't really know if fixing the damage would even fix the board. The cut is deep, short, and narrow, like it was stabbed with an Exacto point. There is visible disruption to copper in the second layer but we can't tell if there is an open, a short, o
Electronics Forum | Mon Mar 02 23:48:22 EST 2015 | vb7007
Hi We are using Universal carrier for a 2 sided PCB, where the bottom side goes for hand solder the switches after wave. Our issue is, we are getting micro solder balls all over PCB bottom after wave, whereas we got numerous vias, which also turns
Electronics Forum | Tue Sep 22 09:59:15 EDT 1998 | Mike C
| Hi Jacqueline! | Do these joints that you're having problems with happen to be on fine pitch solder joints? Are the fillets staying attached to the foot and separating from the pads cleanly? | If that is true, are there many vias concentrated
Electronics Forum | Tue Sep 29 04:54:23 EDT 1998 | Clive Heke
Thank you Steve for your input it was very usefull. I think I skipped a few pertinant details on my initial message though, the component which we found the flux contamination on was on the top side of the board, I was curious if the flux could come
Electronics Forum | Thu Oct 01 19:07:48 EDT 1998 | Paul R. Smith
Kyung Sam, Justin is correct, there is definately either a board design problem or the PCB maker issue. Obviously there are many mixed technology boards built in the world so I would lean towards a design issue as the root cause. Should you or you
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