Subject: | |
From: | |
Reply To: | TechNet E-Mail Forum. |
Date: | Thu, 12 Dec 2002 08:45:08 +0100 |
Content-Type: | text/plain |
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Just add one:
To high pressure during auto load (no soft landing)
Siggi
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Kind regards / Mit freundlichen Grüßen
Dr. Siegmund Zweigart
New Technology Manager
Solectron GmbH
Solectronstrasse 2 Fon. ++49 7032 998 194
D - 71083 Herrenberg Fax ++49 7032 998 222
e-mail: [log in to unmask] <mailto:[log in to unmask]>
internet: www.solectron.com <http://www.solectron.com>
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From: Francis Sun [SMTP:[log in to unmask]]
Sent: Mittwoch, 11. Dezember 2002 17:00
To: [log in to unmask]
Subject: [TN] Solder ball causes
Hello,
I would like to compile a list of what may cause solder balls to
form after
reflow for our internal consumption.
Can anyone add to my limited knowledge on some of the causes that
can
create solder balls?
My knowledge is limited and some may not be correct. If any are not
correct
please point them out.
If there is a comprehensive list available in the public domain, it
would
be great if someone can point me in the general direction of where
it is
located.
Some of the causes that I sort of know of: !! BE WARNED !! some or
all
may not be correct. :
Moisture from substrate and components
Dry solder paste
Wet solder paste?
Stencil aperture(s) too big
Wrong pad geometries
Poor mixing of solder paste
Solder did not reach room temperatures?
Solder paste passed shelf life?
Environment to humidity?
insufficient heat
Dwell time under liqudius is too long?
Dwell time under liqudious is too short?
Time interval too long between solder application and reflow?
Any help is appreciated.
Happy Holidays to all
Francis Sun
MARK IV Industries
(905) 624-3025 ext. 1235
Fax: (905) 624-4572
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Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
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