Add "temperature of the solder is too high"...jk

>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Francis Sun
>Sent: Wednesday, December 11, 2002 11:00 AM
>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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