Sergey,
        Sn96.5/Ag3.5 might do the trick, it's a eutectic alloy with a
meltpoint of 221C. In order to get a robust profile, you will have to
exceed your component 230C by a bit, but they should be forgiving
enough. There's also AIM's Castin alloy, eutectic at 217C....

Mike

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Sergey Ermolin
Sent: Tuesday, December 16, 2003 10:04 AM
To: [log in to unmask]
Subject: [TN] high-temperature alloy and process for a multi-chip module


Hi.

I am desinging a multi-chip module. In my desing, two off-the-shelf IC's
in TQFP packages are mounted on an FR-4 PCB. This board has a Land Grid
Array footptint on the bottom and will be soldered to the motheboard
using a standard reflow process with Sn63Pb37 alloy. What alloy and
temperature profile would you recommend for assembling the multi-chip
module itself? The chips on the module were not designed to withstand
more than 230 deg C and are normally soldered using the same Sn63Pb37
alloy...

Thank you for your help...

Regards,

Sergey Ermolin
Dust, inc
2560 9th Street, #218
Berkeley, CA 94710
510/225-2137

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