PLEASE forgive me but; when is a solder ball a problem?  4 micron or 5 micron?
Please introduce me to the amazing individual who can differentiate visually
between the 2 sizes.

You produce solder balls, and they are a potential reliability issue - FACT!

Having just returned from the French Brasage (Soldering) conference, a good
deal of time was frankly wasted, deliberating on the issue of solder balls:
how they are formed, why they are formed, whether they represent a defect and
if so, at what size do they become an issue -

For goodness sake, if you clean, this is no longer an issue.

The influence of a solder mask and its propensity to produce solder balls is
only a small part of the problem. Are you sure you are producing reliable
circuits? How do you know? You clean to < 10 microgrammes/inch2 NaCl
equivalence - so that means it's OK to leave that amount on every square inch
of your assembly?

Graham Naisbitt


Concoat Ltd                                     Email: [log in to unmask]
Alasan House, Albany Park                       Tel:    +44 (0)1276 691100
Camberley, Surrey GU15 2PL UK           Fax:    +44 (0)1276 691227


-----Original Message-----
From:   TechNet  On Behalf Of Brian Moe
Sent:   Monday, September 29, 1997 6:05 PM
To:     [log in to unmask]
Subject:        [TECHNET] Re[2]: [TECHNET] solder-ball free LPISM?

     We do not experience any problems with solderballs in our
     manufacturing process.  We are using LeaRinol or Probamere
     soldermasks.

     Our wave solder machine is using RMA type flux applied by a spray
     fluxer.  With the addition of a hot gas knife at the end of our
     process solderballs and bridging defects have practically been
     eliminated.




______________________________ Reply Separator
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Subject: Re: [TECHNET] solder-ball free LPISM?
Author:  Phil Bavaro <[log in to unmask]> at ccgate