Jonathan;
Are you sure you don't have an intermetallic layer or is it that you just can't sdee it on an optical micrograph of a cross section.  One problem you run into when you use Sn95Sb5 and you try to compare it to Sn8Pb88Ag2 or even Sn63Pb37 is that there is very little optical contract without the lead (Pb) being present.  You can usually detect the difference between copper-tin intermetallic and the bulk SnSb solder using SEM/EDX if you have good cross sections and if you have really good cross sections you can also also see the difference on optical micrographs.

Regards,
George

George M. Wenger (908)-546-4531 
Reliability Engineer
RF Power Amplifier Group
Andrew Corporation,  40 Technology Drive, Warren, NJ 07059
[log in to unmask]



-----Original Message-----
From: [log in to unmask]
[mailto:[log in to unmask]]
Sent: Monday, October 28, 2002 4:36 AM
To: [log in to unmask]
Subject: [TN] Lead -Antimony experience


Hello Techies:
Does anyone of you have a weird experiences on Sn-Sb alloy for
soldering? (Lead free)?

In my case i have a separation between a Cu surface and the SnSb (95/5)
after HTSL test at the intermetallic layer, in which i can't find any from
88Pb8Sn2Ag solder paste.

Is Antimony can promote kirkendall voiding during the Sn and Cu bonding?
If somebody uses 95/5 (Sn/Sb) for soldering, what are the usual problems,
your were encountering?
Does Sb affects Sn diffusion on Cu metal? If yes what would be the optimum
alloy composition.

Appreciate your help

regards

Jonathan

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