Electronics Forum | Fri May 01 07:22:56 EDT 2009 | kareal
In my project of flip chip PGA production , I found serious delamination in interface of solder mask and first layer copper trace of substrate after UHAST 96hrs( 130C, 85%RH) reliability test. The delamination are always around one type solder bump,
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 | Thu May 07 20:28:35 EDT 2009 | davef
From our notes, the following is a series of snips from: "Copper Dissolution in Tin" LJ Turbini, PhD, adjunct faculty member, University of Toronto, Materials Science and Engineering, SMT 2/07 As the solder becomes molten, copper from the board diff
Electronics Forum | Thu May 07 08:11:58 EDT 2009 | davef
We don't have a good answer for you, but we do have several thoughts on the issue: * First, tin in your solder or solderability protection is going to diffuse into the copper trace or pad on the board naturally. You can stop that by using a protectiv
Electronics Forum | Mon Feb 27 09:09:36 EST 2006 | davef
Silver on your copper or brass part is a solderability protection. The silver diffuses into the solder and you solder to the base metal, either the copper or brass in your case. Soldering to copper is well known. The issues are soldering to brass
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