Hi Eddie - the problems you have brought up on the use of Palladium 
     finishes have been recognized by industry. We (Rockwell) have 
     experienced both great success and tremendous problems with Palladium 
     finished SOICs for both wave and reflow soldering operations. Our key 
     ingredient, along with other companies, is the TYPE of flux you are 
     using. Not all low residue or water soluble or rosin based fluxes are 
     the same! We tested several low residues fluxes and found that 
     specific fluxes did or did not perform adequately. The use of an inert 
     atmosphere (either nitrogen or a vapor phase environment) can give the 
     soldering process an extra boost too. We are reflow soldering 
     Palladium SOICs on military product with very low defect numbers. The 
     IPC 002 (component solderability), 003 (PWB solderability), and 
     Solderable finishes specification committees are all working on the 
     issue of non-tin/lead finishes. I would contact Bob Hall, Solderable 
     finishes task group chairman, through the IPC and see if he has any 
     information the committee can pass on.
     
     Dave Hillman
     Rockwell Collins
     855 35th St NE
     Cedar Rapids IA 52498
     [log in to unmask]


______________________________ Reply Separator _________________________________
Subject: ASSY: SOIC'S IN WAVESOLDERING (fwd)
Author:  [log in to unmask] at ccmgw1
Date:    4/9/96 11:42 AM


     
Forwarded to TechNet for Assistance
Thanks
Dave Bergman, IPC
     
     
---------- Forwarded message ---------- 
Date: Tue, 09 Apr 1996 13:36:48 +0100 (MET)
From: EDDIE VAN HOREN 014 57 20 08 <[log in to unmask]> 
To: [log in to unmask]
Subject: SOIC'S IN WAVESOLDERING
     
David,
I'm looking for help somewhere in the industry on a serious soldering 
problem.
Is there something like a bulletin board where items can be posted for 
discussion?
Today's problem in a nutshell :
     
Subject : wavesoldering of SO-components (mainly SOIC).
     
Since a few years, Texas Instruments has changed the lead finish of the 
SOIC's to a layer of nickel with a palladium flash (simplified).
This can result in 1000 ppm open solder joints when wave soldering.
In the very near future, starting next june, Motorola is also switching 
to a simular leadfinish. All others are expected to follow soon.
In the farther future, useing other PCB finishes than SnPb ( NiAu, 
preservated Cu etc.) will undoubtedly increase the problem.
I see this as a tremendous problem for those people who are 
wavesoldering this kind of components.
Is there a way to find out whether this problem is recognized by users, 
and if somebody sees a solution to the problem ?
And again, is there a way to put questions to the IPC community?
     
Best regards.
Eddie
     
Eddie Van Horen
Industrial Engineer
Alcatel Telecom Belgium
Bell Telephonelaan 2
2440 Geel
Belgium
Tel (32) 14 57 20 08
Fax (32) 3 240 48 02
E-mail : [log in to unmask]