Hi ya Graham,

I'm very interested in replies to this question.

There was a presentation at the last IPC Expo (3 April 2001) that looked at
Thermal Stability of Laminates from Resolution Performance Products.  They
concluded that Tg alone was not a good indicator of thermal performance.
Thermal performance measured by Tg, CTE, time to delamination. (T-260),
temperature induced weight loss and solder resistance.  They found that Tg
within a family materials would indicate a better material choice.

A copy of their report is at http://www.resins-versatics.com/ (click
Applications | Electronics / Electrical Laminating)
or
http://www.resins-versatics.com/resins/resins.NSF/Literature/SC:3039/$file/S
C3039-01.pdf

Hans

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-----Original Message-----
From: Graham Collins [mailto:[log in to unmask]]
Sent: Thursday, November 08, 2001 1:38 PM
To: [log in to unmask]
Subject: [TN] High Tg FR-4


Hello Technet
A question for bare board gurus.   Is there a difference in reliability
between high Tg and regular Tg FR-4 ( IPC-4101/24 vs. IPC-4101/21) in a
vehicle type application?
The end use application is less than Tg of /21 material, so not in the glass
transition range for either material.

Typically - is the CTE different between these two?  (I expect that depends
on the manufacturer to some degree).  If there isn't a high temperature
operating requirement, why select the high temp FR-4?

Thanks!



regards

Graham Collins
Process Engineer,
Northrop Grumman
Atlantic Facility of Litton Systems Canada
(902) 873-2000 ext 6215

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