Hello,
I have seen an increase in problems with electrical testing
and it has been traced
to BGAs.
I have a few questions regarding BGA and
processes. I am trying to
understand if the problem is process related (SMT) or do I have a vendor issue
with BGA.
- Open
contact between the ball and the package. This is verified by pressing onto
the package while testing. Pressing
the package down causes the board to pass.
- Visual
inspection reveals the ball not touching the PCBA. (You may have a ball
in the middle not touching and
the balls on each side are)
- Question: With on ball in the middle not
touching and the balls next to it are, is this indicative to SMT process
issues or BGA package issues?
- Question: What type of inspection can be
performed on BGAs prior to SMT to capture Bad BGA?
i.
Is the industry standard 100% or
Sample inspection for out going
quality inspection?
- Question: Is it easy to identify a BGA
that has been re-balled and if so how?
- Is it customary for distributors to re-ball BGA
- What other test or inspections can be performed to capture BGA
with open contacts?
- As indicated above, pressing down the package causes the board to
pass, how do I detect micro cracking of the solder joint? And what would
cause micro cracking?
I am
lost at this point and am looking for additional suggestions and assistance in educating
me on BGA.
David Harman