Electronics Forum | Mon Jul 28 11:22:46 EDT 2008 | blnorman
Iagree with Matt, normally caused by pad surface contamination. Out of curiosity, what is the PCB metallization?
Electronics Forum | Wed Nov 04 09:47:25 EST 2009 | tstrat
It was 7 wt% according to the EDS spectrum at the EN layer near the ball-pad interface.
Electronics Forum | Thu Jul 22 16:30:59 EDT 2010 | dyoungquist
It is likely that the pads that will not solder have been contaminated. There is something on the surface that is preventing the solder from flowing.
Electronics Forum | Wed Aug 30 23:45:23 EDT 2006 | ppcbs
Since BGA's are sensitive to contamination in the plating process, I always do a simple solderability test whenever we receive a new batch of boards. Take a board from the batch, apply no clean flux on the BGA site, then try to tin the pads with a m
Electronics Forum | Wed Aug 30 23:45:40 EDT 2006 | ppcbs
Since BGA's are sensitive to contamination in the plating process, I always do a simple solderability test whenever we receive a new batch of boards. Take a board from the batch, apply no clean flux on the BGA site, then try to tin the pads with a m
Electronics Forum | Tue Apr 15 21:24:41 EDT 2008 | davef
We find it curious that: * Heat slug pad for Q19 didn't take solder, indicating a pad [board] solderability issue. * Signal termination pads for Q19 didn't flow well, indicating a poor thermal recipe or a pad [board] solderability issue. * Signal ter
Electronics Forum | Mon Feb 21 08:39:10 EST 2005 | pemnut
There are so many variables to this. It could be paste, pad size, contaminated components-pads, placement speed, component thickness being wrong in the program, dropping parts into the paste instead of placing them, component recognition ploblems. Is
Electronics Forum | Fri Jan 13 08:53:53 EST 2006 | chunks
Wave not touching the thru-hole part. Adhesive on the pad. Board mask smear on the pad. Ring contaminated. Ring not plated correctly.
Electronics Forum | Wed Dec 06 21:36:13 EST 2006 | davef
It's surprising that you have that much copper. Copper contamination of leadfree is usually tolerable up to 1%. So, the copper is moving from the pad to the solder ball. Right? If that's correct, the pad requires a buffer material between it and
Electronics Forum | Tue Jul 07 08:42:49 EDT 2009 | ewchong
kpm, you are probably right. under magnification those two pads show some exposed copper which means that they were contaminated or had insufficient solder paste before reflow.
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