The maximum reflow temperature post by chip manufactures.  Following are few
of examles of recommended soldering temperature for Plastic ICs:
Intel (Microprocessor): Peak reflow temp. 205 to 225 C, @ 120 to 130 sec.
Component body temp. Max. 220 C.
National Semi: Peak reflow temp. max. 235 C@ 20 sec.  Recommended 220 C @ 5
sec.
Altera (FPGA): "Ideally, the leads should only be subjected to the peak
temperature (220 C) for approx. 10 sec. to reduce the risk of damage to the
solder and devices.  In addition, the device body temperature which may vary
from the temperature of the leads by as much as 15 C----should not exceed
220 C."

-All the infor. are from the manufactures' recommended "reflow soldering
guidelines for SMT".

Hopefully, this clear up the picture a little....
                                                  joyce

>>> David Gowlett 03/07 1:11 PM >>>
Dear Dr. Mathias,

The problem now facing the electronics industry is maximum temperature that
electronic components can survive. I accept that changes to the design of
circuit boards may help to reduce the degree of overheat.

Can members of this forum provide any information as to the maximum
temperatures that components can survive?

Regards,
David

-----Original Message-----
From: Leadfree [mailto:[log in to unmask]]On Behalf Of Dr. Mathias
Nowottnick
Sent: 07 March 2000 16:23
To: [log in to unmask]
Subject: [LF] ReRe: [LF] SnCu


Dear David
In principle you are right. But sometimes it will be possible to solder
also below the liquidus temperature. Indeed the amount of solid phase of
SnCu2 at 235*C will be only in the range of 2% in the melt. You can
calculate that by the lever rule with the phase diagram for different
temperatures and compositions. From experience I can confirm, that we
have soldered successful with a SnCu3 alloy at 240*C. But I like to
concede, that this must not work for all assemblies.

sincerely
Mathias Nowottnick
Group Manager Joining Technology
Fraunhofer Institute IZM

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