Electronics Forum | Fri May 08 21:53:07 EDT 2009 | kareal
X-section image: tin layer on top of copper trace.
Electronics Forum | Sat May 09 09:40:12 EDT 2009 | davef
The whitish tin layer and the solder mask appear to be incompatible, resulting in adhesion loss.
Electronics Forum | Mon Jun 13 17:23:07 EDT 2011 | grics
What are your Bake Requirements? As in temp, duration, etc...
Electronics Forum | Mon Jun 13 09:25:58 EDT 2011 | milroy
Hi I have seen some of our multilayer PCBs are having delamination issues even after baking them in the ovens. Does anybody faced this issue before? The problem occured after reflow process and wave solder process as well. The temp profiles are well
Electronics Forum | Mon Jun 13 09:43:11 EDT 2011 | mosborne1
Delamination almost always is caused by moisture in the PCB. You can try to keep some of the PCBs in a dry box after recieving them. You can also slowly heat them up to bake out moisture. If you are purchasing boards form overseas form a board house
Electronics Forum | Thu Jun 16 16:50:37 EDT 2011 | boardhouse
Hi Milroy, One thing to check is the FR4 Laminate being used - if this is a RoHs build is the correct FR4 being used by your manufacture. What layer count of board are you seeing the delamination on? Does you board shop Vacuum seal the packages wi
Electronics Forum | Sat May 02 23:31:06 EDT 2009 | kareal
Thanks davef. The defect always occurred during UHAST reliability, but not find in reflow. The key is that there is tin diffuse to copper trace under solder mask. is it a "normal" board defect and what is the potential risk for device? thanks!
Electronics Forum | Fri May 08 04:39:32 EDT 2009 | kareal
Hi Davef, I want to explain that the tin diffusion in my project is not on solder bump/Pad region. It is on copper trace between bumps. so it is very wondering for me.
Electronics Forum | Fri May 08 09:44:23 EDT 2009 | davef
Board fabricators use solder as a resist to protect copper traces from process chemicals. Fabricators remove this resist in later processing. It's possible that board fabrication processing is the source of the tin that you see.
Electronics Forum | Fri May 08 20:59:21 EDT 2009 | kareal
Davef, do you have some information about your mention "tin was used to protect copper trace ans will be removed"? It is very important for my project. Because we are assy and test plant, no any information from PCB vendor. Thanks!