User's Manual

eUniStone
PBA 31309
Assembly Guidelines
User’s Manual Intel Public 44
Hardware Description Revision 1.0, 1-Feb-2013
9.8 Component Salvage
If it is intended to send a defect eUniStone module back to the supplier for failure
analysis, please note that during the removal of this component no further defects
must be introduced to the device, because this may hinder the failure analysis at the
supplier. This includes ESD precautions, not to apply high mechanical force for
component removal, and to prevent excess moisture content in the package during
salvage (risk of pop corning failures). Therefore if the maximum storage time out of the
dry pack (see label on packing material) is exceeded after board assembly, the PCB has
to be dried 24h at 125°C before soldering off the defect component, because otherwise
too much moisture may have been accumulated.
9.9 Voids in the Solder Joints
9.9.1 Expected Void Content and Reliability
The content of voids is larger on LGA modules than for modules with BGA or leads. At a
LGA solder joint the outgassing flux has a longer way to the surface of the solder and it
has a relatively small surface to the air.
The void content of the eUniStone module conforms to IPC-A-610D (25% or less
voiding area/area).
Figure 20 shows an example of void-content at a module assembled at production site.
Normally you can see the whole spectra of void content variation within the same lot
and occasion of assembly.
Figure 20. X-ray Picture Showing Voids Conforming to IPC-A-610D
Voids_IPC_A_610D.vsd