Electronics Forum | Thu Feb 12 11:35:17 EST 2004 | Kris
what is the composition of the paste and ball ? Interesting to know why the customer is asking you to look for it Thx
Electronics Forum | Fri Feb 13 11:19:07 EST 2004 | Evtimov
Hi Bryan The answer is in the paste compozition. Balls of the BGA are usually made by eutetic solder paste.
Electronics Forum | Wed Feb 18 12:42:43 EST 2004 | babe
OK, if the sphere of the ball and the paste on the pad are both eutectic, 63/37 then the paste will reflow first causing a drop of the component, after which the spheres will reflow causing a double drop and a good intermettalic. You can see this by
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 | Thu Feb 12 10:19:46 EST 2004 | Bryan
Hi all, These days our customer asks us to figure out ,during reflow,the BGA ball and solder paste,which will first melt? I think it's very hard to get the rusult.coz I think it'll vary at diffrent part of the BGA,and how can this affect the perf
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 | 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 | Fri Feb 13 11:46:23 EST 2004 | Jack
Is your customer trying to reduce voiding? If the device is using Sn90 / Pb10 and the paste is Sn63/Pb37 the board will melt first. However, if both solders are 183C eutectic, it's a tossup? PCB design, copper weight, bga type (pbga, micro bga, Tbg
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 | Fri Aug 24 13:21:59 EDT 2018 | babe7362000
What do others use as far as solder paste type, stencil thickness and aperature size for a .4mm Ball Pitch CSP. Ball diameter is .3mm. Please let me know your thoughts or what you use. Thanks
