Kevin, OSP is a good surface finish. Most are a LOT better than when they were first introduced in the 1990s. Shelf life will depend in large part on how you store them and the particular OSP you pick. You can get selective ENIG for test points, but then you have to consider where you put them! I have not seen undue damage caused by the use of OSP over say ENIG because of environmental considerations - Coca Cola will do in a PCBA no matter what the finish. :( Yeah, I know you are really talking about atmospheric environments - overall I would say the finish is "average". Bev Blackberry -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Glidden, Kevin Sent: Tuesday, May 21, 2013 12:39 PM To: [log in to unmask] Subject: [TN] OSP processing inputs? Hi all, It looks like I will be getting some PCBs with OSP finish on them to process thru SMT. I've not yet used this surface finish, so for me there are a lot of unknowns. Some background info: 1 The PCBs will be single sided SMT, so I will not have to worry about solderability of second side reflow. 2 We are using Sn63Pb37, not lead-free. 3 We are using water soluble ORM0 paste and DI water wash only (no chemical) 4 We typically process with ImAg. 5 MIL/AERO target service environment I have read some that shelf life is reduced to around 6 months and that OSP covered pads cannot be used as test points and therefore test pads need to be solder coated. I've also read some of the conference papers which seem to indicate corrosion/environmental performance is at least as good as what we would get with ImAg. Any other suggestions / caveats ? Is there an IPC spec for this finish? Thanks in advance! Kevin ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________