Hi Werner,

EDS can not be used to do it. There are several reasones and the major ones are depth of penetration and the surface topography. 

As far as the BP definition is concerned, then I tend to say if the joints can not bare virtually any mechanical load and the layer of electroless Ni is cavitated, then BP is there.

I'm pretty sure you saw/read the definition  before :-)

Regards,

Vladimir

----- Original Message -----
From: [log in to unmask] <[log in to unmask]>
To: Igoshev, Vladimir; [log in to unmask] <[log in to unmask]>
Sent: Thu Jun 19 18:56:11 2008
Subject: Re: [TN] [LF] [TN] SN100 for Reflow Application

Hi Vladimir,
So you have a problem  with the BP definition of: "An interfacial separation with the PCB/component-side fracture surface showing nickel and more than 5wt% of phosphorous and the other fracture surface attached to the solder volume showing either SnNi/SnCuNi-IMC or solder and more than 5wt% of P."
This defines a P minimum, so when you see a problem with more P, it is included.
You certainly can measure the P-content with various techniques—there is nothing magic about 5 wt%, any substantial P-spike in EDS would suffice for the definition.
So, I gave it a try—you do not like it [I do not know why?]—so now it is your turn.

Werner Engelmaier
Future workshops:
Solder Joint Reliability: Parts 1 through 4, July 17/18, Thal, Switzerland
Pb-Free Soldering Processes—Survival, Quality, Reliability, August 18, Orlando
Reliability Issues with Lead-Free Soldering Processes, September 22, Schaumburg
Failure Mode and Root Cause Analyses Reliability (Fatigue, Brittle Fracture, ENIG), September 22, Schaumburg



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