EXCELLENT information. Thanks, Pete.
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Pete Houwen
Sent: Tuesday, July 11, 2006 1:17 PM
To: [log in to unmask]
Subject: Re: [LF] Price premium for Tg = 170 Deg C?
First, beware specifying laminate material for lead free soldering by
Tg.
You can spec a 170 Tg material with an epoxy that breaks down at
soldering temperatures, reducing it's Tg to about 130 after a single
reflow operation. Or you can spec a 140 Tg that maintains it's
properties over multiple passes. Most reflow profiles are not long
enough to cause the Tg to be significant. Far more important are the
CTE, Td, CAF, non-dicy curing.....
When this first became an issue, many companies went right to the
Isola-410 and comparable materials. These are 170Tg, but also have
higher Td, lower CTE, are non-dicy, and less susceptible to
Cathode-Anode failures. As a response to RoHS demand, some suppliers
are now marketing a product with similar properties, but a Tg around
130. For a normal single heating operation, they claim these work, and
they are a bit cheaper.
We have seen inconsistent price increases, but it's between 10-30%,
partly because we were somewhat underspecified in the past, allowing
fabricators to shop around a bit.
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