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Tue, 31 Oct 95 12:58:48 EST
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        I am looking forward to seeing the thermal cycling results. We are 
     having the 'typical' problems with palladium plated parts; poorer 
     wetting when compared to SnPb plated parts resulting in visual and 
     automated inspection failures. The heel fillets usually look good but 
     the toe and side fillets (which are the inspection indicators) do not. 
     They are generally acceptable, but it is taking some time to get 
     consensus on the workmanship standards for these parts. 
     
        Who should I contact to get a copy of the new package qualification 
     guidelines mentioned below?
     
        "The method for testing this should be per the criteria for new
         package qualification being defined by the BGA subcommittee"
     
     Thanks,
     
     Ray Turner
     Cabletron Systems


______________________________ Reply Separator _________________________________
Subject: Re: Palladium plated IC leads.
Author:  [log in to unmask] at !INTERNET
Date:    10/30/95 1:00 PM


In reference to Ni-Pd finished IC leads, the HDP Users group (specifically the 
Telecom Working Group) was formally addressed in the October meeting by a number
of IC suppliers (TI, National, AMD, Amkor, and others) about the acceptability 
of this finish in addition to Tin-lead. Much discussion followed the final 
concensus was - briefly condensed as follows:
Ni-Pd does not perform as well in solderability testing using wetting balance or
other techniques. This also shows up visually making solder joints appear "dry" 
since they do not wet to the same degree. Some of the companies expressed how 
this was causing them problems today.  
The only data presented by TI on solder joint quality was solder joint strength 
testing which has no bearing on long term reliability of the solder joint. The 
criteria required by all was N-50 thermal cycle data.  
The final resolution came down to:
z The Telecom Working Group today accepts Ni-Pd lead finishes from TI, not 
because we want to, but because we have to - or live without parts.
z Assuming reliability data is good, we would rather have "all" Ni-Pd rather 
than mix  parts with Tin-lead, such that the inspection criteria can be 
consistent. 
z Reliability data is really insufficient on this lead finish and needs to be 
provided and presented to the group. TI will review to see if they have the N-50
data for thermal cycling. 
z The method for testing this should be per the criteria for new package 
qualification being defined by the BGA subcommittee -  see above. 
     
Joe Smetana
DSC Communications 
All opinions expressed here are soley my own and do not necessarily reflect the 
position of DSC Communications.
     
     
______________________________ Reply Separator _________________________________
Subject: Palladium plated IC leads.
Author:  GEILAND at DSC-1100
Date:    10/27/95 07:59 AM
     
     
Joe:
     
Wasn't this an issue at the HPD user's conference?
     
     
Ge
     
     
______________________________ Forward Header __________________________________
Subject: Palladium plated IC leads.
Author:  [log in to unmask] at SMTPLINK 
Date:    10/26/95 14:29
     
     
     
     The appearance of the palladium plated lead IC solder joints continues 
     to create anxieties with our customers.  This occurs because they see 
     a solder connection profile which is different than would result from 
     a pb/sn plated lead connection.  Texas Instruments has published a 
     booklet demonstrating and discussing the differences, but this is not 
     completely sufficient to convince some of our customers.  
     
     Is there any 'work in progress' material available from IPC and/or 
     other sources which can be used to graphically educate auditors and 
     customers about acceptable appearances of palladium plated lead solder 
     joints?  Now our auditors and customers reference the IPC-A-610 Rev. B 
     manual.
     
     
     Thank you.
     Myron Papiz
     MSL
     
     
     



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