Electronics Forum | Wed Jun 01 23:09:46 EDT 2016 | slouis2014
Hi, can anybody give an idea how to lessen the void on a double ground pad IC. I have tried to change the stencil design, change the solder reflow setting. but i still haven't reach 75% solderability. thanks alot
Electronics Forum | Thu Jun 02 22:40:13 EDT 2016 | slouis2014
Hi, yes have a few experiments initially i tried to increase the solder volume but component pin have insufficient solder. 1. The solder coverage do you calculate it by solder volume or solder area. 2. if i would achieve as you recommend 50-60 % woul
Electronics Forum | Wed Jul 22 13:50:49 EDT 1998 | Justin Medernach
| My firm has just begun it's first PCB that will use BGA packaging. I have been reading up on the processes involved with BGAs and was wondering if you need to apply solder paste to the pads prior to applying heat and mounting the part to the board
Electronics Forum | Wed Oct 09 20:52:27 EDT 2002 | davef
Russ, Be careful on how you determine your liquidous point. Sure 205-210�C is fine if your paste and the solderability protection on pads and component leads are near eutectic solder and things worked according to plan, but in real life it doesn't
Electronics Forum | Mon Sep 30 09:26:04 EDT 2002 | itempea
Russ, first step would be to get IPC-7095 on BGAs. A few notes: There can be voids in solder balls, or at the solder joints to the BGA, or at the solder joints to the PCB. Various sources or reasons can be responsible for these voids. Voids can be
Electronics Forum | Wed Sep 30 13:10:49 EDT 2009 | spitkis2
Hi guys, Can someone please clarify whether adjustment of Z axis travel is a critical parameter during placement of QFN devices. If so, to within what tolerance? In other words, should a pick and place machine position a QFN down on the board so t
Electronics Forum | Wed Oct 21 08:06:06 EDT 2009 | scottp
I agree with Dave. If the device has a lot of power we'll put thermal vias between the solder deposits with annular rings of soldermask to keep solder out of the holes. We've never had to mess with placement pressure. We've been using QFNs for yea
Electronics Forum | Thu Oct 15 11:04:28 EDT 2009 | spitkis2
Thanks Jim. Pressing the QFN into paste was what I thought of, just wasn't sure if it would cause solder paste to be pressed outside the pad area and possibly bridge with an adjacent pad. Do you recall the ratio of paste coverage to the pad area?
Electronics Forum | Fri Aug 16 10:00:03 EDT 2002 | davef
You have a very bad situation. It�s tough for the gas, flux material, er whatever to escape when the BGA is sitting on top of it and the blind via is blocking it from the other side. Obviously the vias should have been: * Placed on the edge of the
Electronics Forum | Thu Feb 24 20:13:22 EST 2022 | dwl
They don't look that bad, especially for SN100. There is evidence of wetting on the toe and the paste on the pad seems to have reflowed properly. What does the heal look like? That's the more critical part of the solder joint for Gull leaded parts.
