Baking of lead free laminates is something that you will need to consider, specially the longer they sit around. Higher Tg laminates do not always perform better in the lead free environment. Sometimes, depending on the laminate manufacture and your vendor, the lower Tg material has performed better. Also your PCB supplier needs to realize that they need to add some backs on their end such as after etching prior to solder mask and if there is a long hold time between those steps they will need to back again. Moisture absorption appears to be high with the lead free materials.
 
RegardsScott B. Westheimer5709 Clarks Fork DriveRaleigh, NC [log in to unmask]: (919)713-0748Ce: (919)961-5364> Date: Tue, 23 Oct 2007 12:23:09 -0400> From: [log in to unmask]> Subject: [TN] Delamination of lead free PCBs> To: [log in to unmask]> > Has anyone experienced an increase of delamination when processing in a > lead free environment. Typically 4 to 6 layer pcbs during SMT reflow. We > are using the high temp laminate suggested for our process. When we > contacted the supplier and they indicated that any PCBs that are over six > months old should be baked prior to processing. This was never required > with leaded PCBs. > > Is anyone seeing the same condition and similar feedback from your PCB > suppliers> > > > Joel Alexander> Quality Assurance Manager> TT APSCO, INC. > > ---------------------------------------------------> Technet Mail List provided as a service by IPC using LISTSERV 15.0> To unsubscribe, send a message to [log in to unmask] with following text in> the BODY (NOT the subject field): SIGNOFF Technet> To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)> To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest> Search the archives of previous posts at: http://listserv.ipc.org/archives> Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815> -----------------------------------------------------
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