Electronics Forum | Fri Jun 20 03:47:24 EDT 2008 | philip
Hi all, any good recommendation for PbF paste application to reduce voids underneath the QFN thermal pad (stencil thickenss? opening? via hole? reflow profile etc)? We have tried few stencil opening design but no significant improvement as seen. Ther
Electronics Forum | Fri Jun 20 18:32:55 EDT 2008 | hegemon
Back when I used to do a lot of these style devices we ran into the same problem you are describing. Use a pattern for the center pad area and keep the total coverage to about 68% of the pad area. Diagonal Stripes, tic tac toe, cloverleaf, dot array
Electronics Forum | Sun Aug 10 21:57:25 EDT 2014 | cmchoue
Does IPC definition for "QFN Void Ration" ? Like IPC 7095 susgestion the BGA Void ratio.
Electronics Forum | Tue Jan 12 15:29:40 EST 2010 | davef
What is your concern regarding voiding in QFN solder connections?
Electronics Forum | Thu Jul 31 21:57:26 EDT 2014 | cmchoue
What kind of stencil pattern is the best for QFN(Avoid void) Can somebody help me? Thanks!
Electronics Forum | Thu Jun 10 06:15:45 EDT 2010 | muarty
We currently have a project requiring us to place multiple QFN devices (of various sizes). The pick an place is not a problem at all, where we are seeing 'problems' is that 3 of the devices are being place on locations where the ground pad have plugg
Electronics Forum | Tue Mar 14 14:15:03 EDT 2017 | dontfeedphils
I've always been happy with ~25% or less combined voiding on QFN ground pads (depending on the pad dimensions).
Electronics Forum | Fri Jul 19 22:26:32 EDT 2019 | dhanish
Thanks Dave..What is the voids spec for QFN?This is another challenge with the QFN's
Electronics Forum | Wed Mar 15 08:47:50 EDT 2017 | emeto
From what I know, you should follow IPC standard for the class assembly that you are building. From your post somebody mentioned something somewhere - doesn't make it official information. I would not be worried about having voids, but what is their
Electronics Forum | Mon Jan 11 13:31:54 EST 2010 | cbart
I know IPC is working on a spec for voiding for QFN'S. However since its not released I'm curious what others have defined as the max allowable % voiding on the leads (not center ground).
