Electronics Forum | Mon Jul 01 04:50:04 EDT 2019 | sssamw
Yes, No standard.Normally QFN supplier suggest 50-75 um (2-3 mil), but it's very hard to achieve and hard to make consistent stand-off in prodution.
Electronics Forum | Mon Sep 23 01:28:13 EDT 2019 | sssamw
Cannot understood your problem very clearly, please check IPC standard on QFN and its mfg process, also check the QFN supplier's recommendation, so can minimize the bridge.
Electronics Forum | Fri Jul 19 13:09:55 EDT 2019 | edhare
Hi, Are you referring to the condition illustrated here? ... https://www.semlab.com/qfn-solder-fillets In this case, the solder was wicked down an attached un-filled PTH via. Ed Hare SEM Lab, Inc.
Electronics Forum | Tue Feb 11 10:31:20 EST 2020 | emeto
Values and range definitions on your profile attachment are for LF paste not for Tin Lead. Please recheck and redefine, so we get the correct values. Also, which location is the QFN?
Electronics Forum | Tue Feb 11 10:41:30 EST 2020 | dunks
We had this problem at my old job. My understanding (from googling this problem previously) is that the exposed leads on the side of the qfn are not tinned and are not required/designed to have a fillet. Someone correct me if I'm spouting lies.
Electronics Forum | Tue Feb 11 13:03:05 EST 2020 | astarotf
Evtimov The areas analyzed are a standard oven curve according to the pasta we are using. The channels used are only for measuring the oven temperature profile, not in detail of the QFN component sector.
Electronics Forum | Thu Feb 20 07:48:16 EST 2020 | benreben
Hello, The oven profil is not the solution! The only solution for the solder mount on the side is to put gel flux on the side of qfn and make a second travel in reflow . The flux remove oxyde from the copper that is not tinned and the solder is able
Electronics Forum | Sun Feb 23 21:19:08 EST 2020 | sssamw
Yes, this is for tin-lead profile. And for the QFN pins which has copper exposed that not required and not possible to have fillet on side surface as in IPC, see 8.3.13, in IPC-A-610-G
Electronics Forum | Thu Mar 30 08:38:58 EST 2006 | Dan
We have this panel that is Gold Flash. Am I correct in assuming this is technically a lead-free panel then? We are running a WS paste, and the QFN28 has balls of solder instead of a fillet. My Max temp is 216, and the TAL was between 52-57 secs with
Electronics Forum | Fri Jul 13 18:25:09 EDT 2007 | seankim10
It sounds like more has to do with plating. you may also check out the voiding issue especially if you have new FAB or the supplier. I had problems with a RF chip in QFN package due to insufficient grounding that voiding caused. This ground is often
