Hi folks,
     Can anyone direct me to information on the effect of moisture content in PCBs on mechanical properties of the PCB resin and resin/glass composite?  I am particularly interested in possible effect on drop testing of assembled boards.  Thanks.



Best regards,
Leo

          
Leo M. Higgins III, Ph.D.
Sr. Vice President, Engg and Technology
ASAT, Inc. 
13809 Research Blvd., Suite 635
Austin, Texas     78750

office phone   512-249-4758
mobile           512-423-2002
[log in to unmask]
www.asat.com



-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Rob Strecker
Sent: Thursday, August 23, 2007 1:04 PM
To: [log in to unmask]
Subject: [TN] Baking out board moisture


Hi All,

We are having an issue with boards delaminating post oven (oven profiles
are good).  We brought the issue up with our PCB manufacturer and they
said "The absorption of moisture on Tg170 laminate (Lead Free) is higher
than Tg130 laminate." Their corrective action is to increase the bake
time of the inner layer as well as additional drying process of 60min at
150oC before packing.  I am concerned with regards to the high bake
temperature and what it will do to our ENIG finish.  This is also the
recommendation they have given us to bake our existing stock before
running.  Could this reduce the solderability of our boards?  I know
with Tin finishes you would definitely have a problem with the Tin
degrading.  One other odd thing about this is we have been soldering
lead free for about 2 years now and started seeing issues in Jan of 07.

 

Rob Strecker 

 


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