Electronics Forum | Sat Mar 06 02:54:25 EST 2004 | tommy
1)Solder paste selection 2)Reflow profile.Focus on soaking and TAL. 3)Moisture control for BGA. 4)Maybe the BGA solder ball already with void. 5)PCB design.Any via on bga land? 6)Solder masking type. 7)Solder paste volume apply on land. 8)IPC class 3
Electronics Forum | Wed Apr 04 12:35:15 EDT 2001 | davef
These solder balls are where [top / bottom]? Describe the breadth and degree of this problem across all assemblies. Finally, describe your wave solder machine, a common profile for this board, and the board [beyond that it's mixed tech, like are
Electronics Forum | Fri Mar 04 15:22:17 EST 2005 | russ
Glad to hear a little success from ya Duckmann! i have stenciled mask in the past and I can tell you that stencils are expensive. They are basically a step stencil, you will need full thickness for the area(s) you are going to apply mask and you wi
Electronics Forum | Wed Feb 07 21:58:38 EST 2001 | davef
We are reviewing our shelf life policy and have the following items listed as shelf life sensitive: Printed circuit boards, peelable solder mask, solder paste, moisture sensitive parts, multiwire printed circuit boards from Icon or Hitachi, NiCd batt
Electronics Forum | Thu Oct 08 03:59:26 EDT 1998 | Charles Stringer
Does anyone out there have hands on experience of selective soldering. Either masking or miniwave type. I am looking for pointers with regard to equipment selection and known process problems/ limitations
Electronics Forum | Thu Jan 06 16:11:07 EST 2005 | Chunks
It appears your board house is having a problem with the solder resist (mask). From the couple pix it appear that the holes are being plugged by the mask, so your HASL is not able to be blown out during the hot knife process. Time to call your boar
Electronics Forum | Sat Oct 06 08:27:24 EDT 2001 | davef
Yes, some solder masks do not tent well, because the material is too thin. That�s the trade-off. Thin masks: * Conform well to [don't bleed onto] fine pitch features. * Tent vias poorly, requiring an additional "plugging" step. As you imply, if th
Electronics Forum | Mon Mar 29 14:58:08 EST 2004 | davef
Josh: Final cure of the LPI solder mask: 310*F for 45 minutes. Your board fabricator needs to do a better job. Most fabs do not check cure, because the processes subsequent to cure are so brutal that the fab expects the following process to highlig
Electronics Forum | Sat Aug 27 09:47:05 EDT 2005 | davef
From the pic, we see blistering, but none so close to via that we'd attribute the blistering to via, via plugging, or anything of the sort. When we see blisters like this, we think of a surface contaminant being present on the boards at the time of
Electronics Forum | Wed Feb 21 08:06:23 EST 2007 | davef
The cause could be a lot of different things. As long as you didn't use excessive reflow temperatures, we'd guess that: * Solder mask blister: Your board fabricator should be able to demonstrate through TMA [or equivalent] analysis that the mask wa
