Earl,
I concur that either solder paste or paste flux will work for BGA rework. I
have wondered though if the slightly lower standoff would make any
appreciable difference in long term reliability. Certainly it does not in
the short term. Earl, is your statement about long term reliability based
on field data or temperature cycling or both?
We'll need your full address if you really want us to take you up on that
info offer. Aren't you afraid you might get 1600 requests or even 160!?!
I will take this opportunity to go untechnical for a minute:
It sure is great to be employed again and back in the technical end of the
business. Thanks to Jack Crawford, Paul Klasek, Tim Crawford, Dave Hillman,
Doug Pauls, Gordon Davy, John Sohn, the folks at Universal, EMPF, Peter
Brattin (ECI) and a whole host of others on and off TechNet for their
support and hand-holding.
sincerely,
Bev Christian, PhD
Materials Lab Manager
Research in Motion
295 Phillip Street,
Waterloo, Ontario
Canada N2L 3W8
519-888-7465
Fax 519-888-7884
-----Original Message-----
From: Earl Moon [mailto:[log in to unmask]]
Sent: February 6, 2001 4:32 PM
To: [log in to unmask]
Subject: [TN] Lead trimming, BGA rework, and Nortel
It used to be that clipping into a through hole component solder joint was a
no no because it could cause a fracture thus rendering the joint suspect.
Concerning BGA rework, paste flux works as does solder paste because it
ensures compliance from the board surface solder termination areas to the
balls. Therefore, solder joints are formed. Ran thousands with SRT 1000 at
HP and found no initial solder joint quality or long term reliability
issues. Liquid flux don't get it. Also, raised SRT Pro nozzle up to .100"
above board to get adequate hot air circulation but had to contend with
adjacent component damage unless shielding in place.
Finished 14 week Lean manufacturing adventure. Have 115 slide presentation
available to those sending recordable CD and self addressed/stamped
envelope. Pretty exciting stuff to me but maybe not to seasoned Lean
veterans.
Finally, am now working with Nortel/Antec joint venture as Arris
Interactive. Doing what I love best as DFM/CE. Wonder if any old Nortel
veterans still around (Bev) to say whether a DFM manual exists and available
to associates? Got many DFM check lists, tons of IPC stuff that I follow to
the letter, and some other non-specific stuff but would like not to
re-invent the wheel.
Thanks folks,
Earl Moon
Proof Of Design
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