Mail*Link¨ SMTP [TECHNET] BGA DFM and thermal management
A PCB design engineer asked me: What potential difficulties will he
see by placing numerous components under a BGA? My answers are:
- Affect BGA solder joint reliability due to less compliance. - Can
cause insufficient support at repair if too dense.
- The bottom component can affect x-ray image quality (especially
Metal
Cap.)
- In case that no solder mask is required to plug the vias in design,
then difficult to apply masking tape before wave soldering if needed
However, due to density restrictions, he has to do it. I think the
above are desired but not mandatory, is it right?
He also asked: does having four power planes affect the thermal
transfer at all? Any answers?
Thanks,
Yuan