Hi Russ - You are one of the first folks I have heard that are using a palladium finish on QFP - there is a wide distribution of SOIC components (Texas Instruments) with a palladium finish in the industry. Two issues with palladium that may be of assistance to you: (1) flux dependency, (2) dissolution rate. The testing I have completed shows that my ability to form a good solder joint with a palladium finish is highly dependent on the specific flux activator. Having an inert atmosphere (either vapor phase or nitrogen) was not a significant factor. Palladium has a slower dissolution rate into solder than other metallics you typically deal with (i.e. silver, gold) which means you may have to alter your soldering profiles to allow for more soldering time. How thick is the palladium finish? Some recent published data shows two camps of thought - palladium can cause a solder joint to crack and palladium won't cause a solder joint to crack. Also how are you testing the solderability? The next revision of JSTD-002 will include a surface mount simulation test method which has been show to be more applicable to SMT components than the dip and look test. Good Luck. Dave Hillman Rockwell Collins [log in to unmask] ______________________________ Reply Separator _________________________________ Subject: assembly Author: [log in to unmask] at ccmgw1 Date: 4/10/97 10:06 PM Hello Technet, Is anyone out there experiencing solderability problems (dewetting) on QFP fine pitch devices that are Palladium plated or coated over nickel (copper lead frames)? The parts in question are 4 - 6 months old. Storage is open; Parts are baked at 125C for 24 hours prior to placement. Paste used is RMA 390 DH3. Reflow is forced convection (BTU VP98). Any help on this issue would be greatly appreciated!! Russ Vertefeuille Mfg. Eng. Honeywell *************************************************************************** * 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] * ***************************************************************************