Electronics Forum | Tue Feb 17 01:15:26 EST 1998 | J.H Kim
| In solder bumping in flipchip technology by solder printing, | the precise control of solder volume and height is very difficult. | Therefore I'd like to know the solution of this problem. | Thanks
Electronics Forum | Tue Feb 24 01:19:01 EST 1998 | Jon Gruett
You are right !!! The exact volume of solder paste onto flip chips is extremely critical. Only one vendor that I know has taken that part of the process to the next level, whereby they can effectively deposit the right amount onto the flip chip exa
Electronics Forum | Wed Mar 21 20:40:28 EST 2001 | dblsixes
We are building a monster ... Dimensions are 10" x 7" ... 12 layers ... A Logic Assembly with a Power Supply all rolled into one ... The Power Supply is in one section of the board, the logic in the other section ... The Power Supply obviously has a
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 | 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 | Fri Oct 09 00:57:05 EDT 2009 | jjmag921612000
SteveO, I had personal experience with this using a Panasonic MPAV2B. It took a while, but I believe the end result was to have some additional "Z" travel to press the QFN into the paste. Also, the design of the paste on the ground was key to keep t
Electronics Forum | Thu Mar 22 16:06:22 EST 2001 | dblsixes
Our next plan of attack is to dog-bone the solder aperature. By reducing the width of the solder paste at the heel, we hope to slow the flow up the leg of the pin while the temperature of the pad catches up. We have boards that were HASL ...
Electronics Forum | Thu Mar 22 21:53:49 EST 2001 | davef
Don't mess with the doggie stuff until you get longer pads [and then you won't have to mess with it] because you'll just ruin your lead definition with more paste and still not have the heel fillet you desire.
Electronics Forum | Sat Mar 24 16:34:06 EST 2001 | Stefan
Can you increase the placement force on your P&P machine? It should squeeze the solder paste to all sides including the heel.
Electronics Forum | Fri Oct 16 14:45:58 EDT 2009 | cyber_wolf
Many pick and place platforms rely on nozzle spring pressure to determine how hard a part is getting pushed into the paste.