Electronics Forum | Tue Aug 19 12:15:37 EDT 2003 | D Peter
Again, that is for packaging, rather than moisture removal or storage. Those guidlines are for several reasons, preventing low pressure outgassing or disassociation of the dessicants, damage to parts or wafer tray due to forces on the evacuated pack
Electronics Forum | Tue Feb 12 17:57:42 EST 2008 | chef
I must ask the silly question- are you sure you deposited the correct amount of paste? Depending on aperature design-the voiding could come from a stencil that has its holes partially built up with old paste. If paste volume is guaranteed, then what
Electronics Forum | Fri Jun 20 18:32:55 EDT 2008 | hegemon
Back when I used to do a lot of these style devices we ran into the same problem you are describing. Use a pattern for the center pad area and keep the total coverage to about 68% of the pad area. Diagonal Stripes, tic tac toe, cloverleaf, dot array
Electronics Forum | Thu Aug 20 08:23:23 EDT 2009 | ratsalad
One diagnostic tool that I have found useful in the past is the "hot plate test". Place suspect components and/or PCB's on a hot plate and turn it on High. Then observe. Granted the conditions on the hot plate are not the same as in a reflow oven,
Electronics Forum | Thu Jun 28 17:05:46 EDT 2012 | davef
Here’s what we seem to know: * There’s a problem with voiding in the solder connections of SMT capacitors * A void is an open area caused by air or process fluid that is trapped within a solder connection * Voids are an allowable condition as long as
Electronics Forum | Fri Feb 01 19:07:57 EST 2013 | hegemon
We have had some success in void reduction with LGA by pre-tinning or "bumping" the devices before placement. The extra solder seems to allow a slightly higher standoff, and allows better outgassing, is my guess. A lot more labor , but the results
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 | Thu Jun 22 15:05:55 EDT 2017 | solderingpro
There are several different technologies in the industry today to assist in the out-gassing of flux cores. On automated soldering systems, there are two main types of perforating solder feeders: - Hole Drilling - "V" Scoring By perforating the so
Electronics Forum | Thu Sep 26 14:45:36 EDT 2019 | dwl
Excellent X-ray picture, very helpful! It looks like you have a lot of voiding on the center thermal pad. My guess is that outgassing is pushing solder off the pad which is forming solder balls outside the body of the component package. The first
Electronics Forum | Fri Jun 23 08:52:16 EDT 2000 | Dave F
John: Seek your answers in the archives. As I recall someone said: � Biggest cause of BGA shorting was out-gassing in-package moisture. � Removing shorts w/o removing the device: - Preheat the board - Lower the nozzle and heat the device - Lift the
