Electronics Forum | Wed Jan 27 20:11:36 EST 2010 | plerma
What material is used to cap a via? Is it the > standard LPI Process/Material? we tent vias all the time, mostly to assist with assembly and the majority of the time outgassing is not a problem. What is the purpose in your case?
Electronics Forum | Mon Apr 12 22:22:01 EDT 2004 | davef
Large voids are common in via in pad [seach the fine SMTnet Archives for earlier laments], especially in blind via. Observations on your via out gassing theory: * If the copper plating on your via is GT 1 thou, there will be no outgassing from the
Electronics Forum | Mon Apr 12 08:10:17 EDT 2004 | wgaffubar
We are sometimes, not always, seeing very large voids in the solder joints of BGA's with Via in Pad. Some lots of PCB will have the voids and other lots of boards will not. I feel the via's are outgassing during reflow, due to the PCB not having been
Electronics Forum | Wed Sep 17 03:15:40 EDT 2003 | Daan Terstegge
Are there via's underneath the Tantalum, closed with soldermask on the other boardside only ? I've had a situation recently where a chip resistor was blown away by the outgassing of via's under a Tantalum. The presence of the Tantalum caused the vap
Electronics Forum | Fri Apr 15 11:16:03 EDT 2005 | HOSS
It's a longshot but.....I have seen low-standoff parts move caused by via's under the part erupting from within internal layers (outgassing). If this is a multilayer PCB and vias are not well plated or pourus, they can and will expand when heated.
Electronics Forum | Fri May 31 18:00:55 EDT 2013 | hegemon
With regards to first picture.(Large themal vias) I would attempt to measure the area of the ground pad, less the area of the "drain" holes or Thermal Vias. From that result I would reduce the aperture to account for about 50% coverage of that remai
Electronics Forum | Tue Aug 22 14:52:55 EDT 2000 | John Thorup
Jax - absolutely right - the archives are a valuable tool and deserve to be used more than they seem to be. Caumel - Are your blobs on the solder side or the component side? Are your vias tented on the component side? What size are your vias? Is th
Electronics Forum | Tue Mar 24 11:20:18 EST 1998 | Earl Moon
| Anyone have an idea how small a via must be to inhibit significant solder volume escaping into the via? Typically, micro vias are drilled and plated to about .003" diameter. To avoid significant solder "drain off," they should be drilled as shallow
Electronics Forum | Sun Jan 23 13:16:02 EST 2000 | Mike Gamble
No insult intended but you are either brave or being bullied by design. My guess is the latter as no assembly plant really likes doing things against the grain of norms. We have done Via in Pad with reasonable success but it is fraught with hidden tr
Electronics Forum | Wed Mar 25 16:38:21 EST 1998 | Steve Joy
We have successfully put .016" vias in .030" pads. There is no issue with .030" solder balls, since the actual volume of the .002" via in pad is small compared to the ball+solder paste volume. We did notice random bubbles where, apparently, the sol
