Electronics Forum | Tue Nov 27 14:24:13 EST 2001 | mparker
Short term fixes can be: have the vias "plugged" with solder by the fab house. This works if your fab is HASL finish. Tent the vias with solder mask, top side only. You may get a flux entrapment issue in the vias with this manner. Long term fix can
Electronics Forum | Wed Mar 27 18:23:01 EST 2002 | kmorris
Does anyone have experience doing conformal coating over Plastic BGA in High-Rel PCB assembly? Is underfill necessary to avoid problems with entrapped air, etc? Our application is a 17x17mm BGA, 256 I/O. We are assembling with a water soluable pas
Electronics Forum | Thu Jul 03 15:03:39 EDT 2003 | Jim Nunns
My design group wants to change our route keep out around all SMT parts to 5 mil even under the parts with zero standoff. Are others in the industry routing under parts that have no standoff? My fear is that we will get shorting if the mask is scaped
Electronics Forum | Tue Dec 14 13:26:19 EST 2004 | Peter
I have a question regarding post cured property of SMT adhesive. If after component placement, the epoxy dot gets compressed and bridges between the 2 pads, what would the impact on the circuitry? Would it pose risk for flux entrapment? Could the cu
Electronics Forum | Fri Jan 21 16:50:33 EST 2005 | Board House
I work for a board house and our proceedure for this process is the following, We cover the via pads leaving the hole open and then apply the surface finish and then go back and Cover the Via with a second operation. By doing this you do not entrap
Electronics Forum | Fri Aug 26 17:27:48 EDT 2005 | saragorcos
Hello there, Most probably, since the solder balls are entrapped, it is a process indicator, but refer to IPC 610-6.5.3.1 on Excess solder / solder balls / splashes - it really depends on what class you are manufacturing, and the minimum electrical c
Electronics Forum | Wed Feb 01 18:11:43 EST 2006 | Chris
I wonder if they are concerned about getting chemicals trapped in the tented vias. If the tented vias have pin hole openings or even larger openings, chemicals from the ENIG process could become entrapped in the via holes and not washed away in the
Electronics Forum | Wed Jan 17 07:55:11 EST 2007 | pavel_murtishev
Vladimir, Phil J is right. Tantalum�s moisture vapor outgassing is the root of the problem you are searching for. Internal pressure of entrapped moisture becomes very high in reflow zone. Vapor jet shifts your components and affects BGA�s bumps. Bak
Electronics Forum | Sat Feb 03 08:56:09 EST 2007 | davef
Multiple leads in a single PTH is prohibited because: * Need to be able to remove and replace any component without impacting another. * Oversized hole required will result in increased solder defects and could also lead to flux entrapment. * Counte
Electronics Forum | Tue Feb 06 23:01:44 EST 2007 | Wayne
The QFN is found to have contact problem during FCT. The paste that I am currently using is SnPb 63/37 water soluble paste. Is it because of water soluble paste? (unable to clean after reflow process as QFN is entrapped by paste/flux) Should we use
