Hi Christian -
     
     We do a bunch of SEM-EDX (Energy Dispersive Xray) as a method of 
     getting a snapshot of what is happening. The EDX technique is good to 
     about 0.5 atomic weight percent and can look at small areas. Using the 
     Auger microscopy techniques you can get down to 0.1 atomic % and a 
     much smaller analysis region but not everyone has an Auger sitting on 
     their desk. There are other electron microscopy techniques (ESCA, 
     SIMS,etc.) but you really just want to get a general idea of what is 
     happening with the solder joint metallurgical composition and not do a 
     exhaustive investigation - the simpler SEM techniques will give you 
     that information. My preference is to look at a scan/raster area that 
     includes the whole solder joint first and then do point scan/rasters 
     on solder joint areas that look to be segregated. Based on these 
     general results you can decide if additional solder joint reliability 
     testing is warranted. As for solder joint reliability, thermal cycling 
     with continuous electrical monitoring of the solder joints has worked 
     well for me. Good luck.
     
     
     Dave Hillman
     Rockwell Collins
     [log in to unmask]


______________________________ Reply Separator _________________________________
Subject: Re: Solder compatibility
Author:  [log in to unmask] at ccmgw1
Date:    7/11/97 8:25 AM


Dave,
     
in your reply you recommend the use of Scanning Electron Microscopy analysis 
techniques. As far as I know there are some methods available - single point, 
areal
and others, depending on the required analysis resolution. Talking about a 
final
composition of Sn/Pb/Ag (even some small zones only) what analysis technique 
would be recommendable ? Furthermore, any recommendations for Solder Joint 
Reliability Testing?
     
Regards,
     
Christian 
     
*************************************************************************** 
* TechNet mail list is provided as a service by IPC using SmartList v3.05 * 
*************************************************************************** 
* To subscribe/unsubscribe send a message <to: [log in to unmask]>   * 
* with <subject: subscribe/unsubscribe> and no text in the body.          * 
*************************************************************************** 
* If you are having a problem with the IPC TechNet forum please contact   * 
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask]      * 
***************************************************************************
     

***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]>   *
* with <subject: subscribe/unsubscribe> and no text in the body.          *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact   *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask]      *
***************************************************************************