Hi Leland,



Cross-section won't tell you much. If you wave solder was "contaminated" over time with Cu, you can try to use EDS to compare both of the solders. Another hope is  the elemental composition of the fluxes. If they are different, then you can use the same EDS to tell them apart.



Regards,



Vladimir

------Original Message------

From: Leland Woodall

Sender: TechNet

To: [log in to unmask]

ReplyTo: TechNet E-Mail Forum

ReplyTo: Leland Woodall

Sent: Oct 28, 2009 07:54

Subject: [TN] Birth of a Solderball



TechNetters,



Is there any possible way to determine the origin of a solder ball?

We've had a failure because of one, and we're trying to determine

whether it came from our SMT or wave soldering process.



We use SAC305 at both, so using the SEM to determine alloy composition

is not really helping.



The ball itself is spherical with no "tails" and quite shiny in

appearance.



If we cross section the ball, will we see a difference in grain

structure due to the differences in cool down rates?  Is there anything

else we can use or do?



Thanks in advance for your help!



Leland



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