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August 2004

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Subject:
From:
Richard Kraszewski <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Richard Kraszewski <[log in to unmask]>
Date:
Mon, 16 Aug 2004 08:12:12 -0500
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Speaking from experience, merely calling out a higher Tg for lead-free
can may cause you some pain. You also need to be sure that the Td
(thermal decomposition point) is elevated above your maximum process
temperature. If not, you may be susceptible to measling/delaimination.
One way to insure this is be sure that the laminate is not DICY cured.
Check out some of the technical papers at   www.isola-usa.com.

Rich / KEDS 
 
 


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Gregg Klawson
Sent: Monday, August 16, 2004 8:03 AM
To: [log in to unmask]
Subject: [TN] Laminate Tg specifications


What is the best way to specify laminate glass transition temp
(Tg)?   These are the types of products we deal with, any
recommendations
on what Tg's we should call out?  Call them all150C minimum and be done
with it?  And what about lead-free processes with higher reflow temps,
do we need higher Tg's?

1.) Standard through-hole 6 to 10 layer wave solder single pass, assume
2x rework
2.) Standard SM 8 to 16 layer, 2x SM reflow, 1x wave solder palletized,
2x rework
3.) Complex SM 12 to 24 layers, 2x SM reflow, 1x wave or selective
solder, 2x rework

Thanks in advance for your wisdom.

-- Gregg

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