Electronics Forum | Thu Apr 11 00:54:49 EDT 2019 | SMTA-Vikram
Yes, we have try different Flux, probes. etc... also not to paste vs Paste Via, but still we have ~3% NDF due to contact issue. I am looking for selective pasting with less flux dispenser.Any idea or anyone has used? What about plug via before pas
Electronics Forum | Tue Nov 20 12:48:40 EST 2001 | tony_sauve
We recently experienced a problem w/voids (up to 65%) in uBGA solder joints. The only joints that have the problem correlated to pads which had blind 0.006" via's in them. The via's only extend down 2 layers, of the 18. 21 BGA's on the PCB, only expe
Electronics Forum | Wed Apr 03 19:02:16 EDT 2019 | SMTA-Vikram
We still use Via as test points. so we need to paste Via. Pasting will make better contact with probes compare to test via without solder.
Electronics Forum | Fri Mar 29 07:53:12 EDT 2019 | davef
Why are you printing paste on test via? In the old days, we probed soldered pads to cushion impact force of probing. Is that still a reasonable practice?
Electronics Forum | Fri Mar 29 00:18:05 EDT 2019 | SMTA-Vikram
3% NDF. We using 8oz 90 degree blade type razor probes, still same issue. Is there stencil we can use or selective pasting test via so flux will not build in testvia. any help or guidance will be appreciate.
Electronics Forum | Wed Apr 16 11:20:31 EDT 2003 | russ
What was the original complaint? when you say solder wicked onto top of capacitor do you mean it was dewetted from the board and only on the cap? What type of device showed voiding? how bad was it 20%,50%? I have found that the paste type seems to
Electronics Forum | Thu Apr 17 10:38:02 EDT 2003 | davef
While Russ is correct that a little voiding is OK, your level of voiding [customer complains that the solder surface looks bumpy] doesn't give us the ol' warm and fuzzy about their process control. For background: * Search the fine SMTnet Archives.
Electronics Forum | Thu Apr 17 16:43:09 EDT 2003 | davef
Background: * Bulwith, Ronald A., �Failure Analysis of Solder Joints�, �Insulation/Circuits� magazine, February 1978 * Banks, Donald R., et al., �The Effects of Solder Joint Voiding on Plastic Ball Grid Array Reliability�, Proceedings of the Technica
Electronics Forum | Wed Apr 16 10:45:16 EDT 2003 | Takfire
Recent cross-section analysis for a customer complaint revealed voiding in the solder fillet. In some cases, the remains of outgassing were also observed. During the failure analysis, we also observed failures where the solder fillet wicked on the
Electronics Forum | Wed May 07 09:21:46 EDT 2003 | davef
Here's some papers: * �Voiding Of Lead-Free Soldering At Microvia�; Dr. Hyoryoon Jo, B. Nieman, and Dr. N.C. Lee Indium Corporation of America; SMTA International; 09/22/2002 * �Solder Joint Formation With Sn-Ag-Cu And Sn-Pb Solder Balls And Pastes�;
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