Paul
The parameter that is most important in this case is Td. Most laminate
suppliers are now stating this value for their products. In general
terms it is the temperature at which 5% of the material will dissipates
and there is an IPC test method for this measurement. As to what Td is
required for your lead free process an evaluation will most likely be
required or you can simply select a high value, 360 C, and be reasonably
assured their will be no decomposition during the process.
Best regards
Lee
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Black, Paul
Sent: Wednesday, November 24, 2004 3:08 PM
To: [log in to unmask]
Subject: [TN] FR4 and Lead free
Hi Tech Gurus,
As people talk more and more about Lead free, I keep hearing that
standard FR boards might not be able to take the extra heat required for
a reliable Lead free solder joint. The problem is that I keep hearing
the word MIGHT. I have not heard that this is definitely true and, if it
is true, I have not heard anyone offer a cost effective solution. So, I
am asking the many experts on this forum, will standard FR4 be able to
handle the higher excursions (particularly, let's say, for a 7" X 9", 8
layer, double-sided SMT, .062" 5/5 board) associated with Lead free
solder paste? If not, what would be the most cost-effective offering
(i.e. high Tg FR4)?
Thank you,
Paul Black
Manufacturing Engineer
Kronos
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