Electronics Forum | Thu Aug 10 07:29:43 EDT 2017 | stivais
How do you evaluate the soldering quality for those QFNs? X-Ray or AOI? For some QFNs (and other bottom termination components) it's not supposed to have solder fillets on toes. It's also noted in IPC-A-610 (Rev.F 8.3.13). Take a look at your QFN ch
Electronics Forum | Fri Jul 15 13:58:32 EDT 2005 | seaK
Our production is putting QFN40 and QFN56 package on board. With 80% opening on terminal, 40% on thermal pad, we found QFN56 100% forming toe fillet, but it does not work out the same to QFN40. We suspect it's because of the weight of component.....
Electronics Forum | Fri Jul 08 16:35:04 EDT 2005 | Jason Fullerton
"Whether or not you need a toe fillet depends on your application. We have high reliability products where we can't use a QFN over a certain size, regardless of toe fillet. We have other applications where we meet the thermal cycle requirements for a
Electronics Forum | Wed Jul 06 14:36:05 EDT 2005 | Bob R.
The only way we can consistently get a toe fillet is to use a paste with an extremely active flux. We allow that paste on certain products, but discourage it's use because it's on the hairy edge of not meeting our lower limit in surface insulation r
Electronics Forum | Tue Jul 04 14:50:52 EDT 2017 | dleeper
Thanks! good stuff. I am disappointed the IPC has put off updating QFN solder filet specs till rev H. It's a pet peeve of mine trying to argue with customers that a visible toe filet on a QFN is not necessary, and may not even be possible depending
Electronics Forum | Mon Jul 22 02:13:31 EDT 2019 | jandon
some PQFN package configurations have no toe exposed or do not have a continous solderable surface on the exposed toe and a toe fillet will not form. (IPC-A-610F 8.3.13)
Electronics Forum | Fri Dec 22 16:04:26 EST 2006 | mika
Hi, This Not so easy as one wuold think. Has the thermal pad of yours vias? How many? What's the via's dia? What is the pcb thickness? If the the pcb has a "ground layer" connected (vias) to the pcb thermal pad, it could sometimes be a little bit tri
Electronics Forum | Wed Jul 06 12:25:55 EDT 2005 | HOSS
Bob, We have seen this same issue and haven't found a solution other than touching up to create a toe fillet. Luckily, it's a low volume product, for now. What have you done to combat this? Thanks.
Electronics Forum | Mon Jun 27 09:38:30 EDT 2005 | Bob R.
What problems are the quality people seeing? I hope they aren't expecting a toe fillet. QFNs are typically cut from an array after plating. This leaves exposed copper on the sides of the part. We'll often see smearing from the sawing process that
Electronics Forum | Thu Jul 05 15:13:46 EDT 2007 | joeherz
We've seen non-functional QFNs cured by touching up the toe fillets. Especially with parts that are not plated on the edge/face where you get minimal/no wetting due to oxidation of bare copper. I'm not suggesting that you touch everything up but th
