Electronics Forum | Fri Dec 27 14:11:18 EST 2002 | cnotebaert
We have placed these parts. I have not had problems with them but when I designed the stencil we reduced the app for the large thermal by 20% to reduce the chance of problems like your having. If the balls are close (.040-.050" or
Electronics Forum | Wed Feb 19 22:08:21 EST 2003 | davef
We usually end-up emailing reports and pix to each other. Fire a copy off to me.
Electronics Forum | Fri Feb 20 15:07:31 EST 2004 | agp
I agree with Jay. The paste will reflow first before the balls. The main reason is the flux content and the dimension of the spheres.
Electronics Forum | Fri Feb 27 11:33:32 EST 2004 | Bryan
Very strange question,but interesting.Is there anyone who have conducted any experiments to figure out the results?I made a profile board,one thermal couple on pad and other one drilled into the ball of BGA.the 2 points are perpendicular to conveyor
Electronics Forum | Sat Dec 28 02:58:12 EST 2002 | emeto
If the problem is in the big thermal pad.The surface strains in that pad are different then the others and through the reflow period there is an affinity between them(only if they are too close). I recommend you to reduce the theramal pad. Make smal
Electronics Forum | Fri Feb 20 13:01:26 EST 2004 | Jay
First, it depends on the alloy composition of the solder. As you might know, eutectic Sn/Pb solder has the lowest melting point among available conventional solder systems. (except those based on Sn-In and Sn-Bi systems.) For example, 63Sn/37Pb - 183
Electronics Forum | Tue Feb 17 04:52:13 EST 2004 | John W
There's normally a number of reasons people want to know what melts 1st, 1 - to see if you know, 2 voiding issues - whole can of worms 3 device alignment. One of our collegues has said that most balls are Eutectic, that's in fact not totally correct.
Electronics Forum | Wed Nov 14 13:05:40 EST 2007 | rgduval
I had one project with micro-vias in 0805 and larger pads, with no issues. But my most recent project had vias that were larger than the 0402 pads that the via was in. To the point that for a number of the lands, there was no visible pads (a couple
Electronics Forum | Wed Jul 14 16:59:52 EDT 2010 | swag
Solder paste on the pads will keep part aligned. If you do not use paste, you will need to apply tacky flux. You should not run without one or the other.
Electronics Forum | Thu May 05 16:18:47 EDT 2005 | jimmiem
The black pads that we see are on the BGA component. We removed the component from its site and on 2-3 pads 100% of the ball stuck to the pad on the PCB and the corresponding BGA pad was black.
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