Electronics Forum | Mon Apr 29 10:07:00 EDT 2002 | geoff_goring
I need to find out about tin/lead diffusion and how this causes solderability problems in device lead-outs. This is not to be confused with an earlier thread of Zn/Pb diffusion - unfortunately this is was a typo.
Electronics Forum | Mon Apr 29 22:32:59 EDT 2002 | davef
See, I didn�t bite on you zinc diffusion trick that you tried to pull last week. Understand, in this response, I am NOT trying to bust you. I�m trying to determine what you are looking to understand. [Some times I get so locked into talking a cert
Electronics Forum | Wed May 15 10:55:35 EDT 2002 | geoff_goring
As I thought..... This is probably why most journals and standards I have studied hold shy of even attempting to predict shelf life. They certainly hold off of any predictions when based on accelerated life testing too. The component lead is a cop
Electronics Forum | Fri May 03 06:03:26 EDT 2002 | geoff_goring
Dave Many thanks for your very informative piece on SMT.com As we stand we have not yet 'seen' any problem. My issue is that we have ordered (LTB) a very large quantity of ASICS and our usage has taken a down-turn. We therefore need to keep the one
Electronics Forum | Mon May 20 10:49:12 EDT 2002 | geoff_goring
Are we saying then that IMC can occur at the solder / Cu pad join on the PCB when finished assembled? In our case we are being told that this process is starting before assembly. Is it fundamentally the same thing. i.e. will the Tin diffuse with th
Electronics Forum | Mon May 20 21:29:52 EDT 2002 | davef
Q1: Are we saying then that IMC can occur at the solder / Cu pad join on the PCB when finished assembled? A1: Yes, but in a broader context I am saying that when someone solders correctly, they form an IMC. Q2: Will the tin diffuse with the Cu over
Electronics Forum | Fri May 03 18:55:41 EDT 2002 | davef
Interesting situation. Everything [ie, intermetallic compounds, solderability, etc] is speculative without knowing more about the materials of: * Leads. * Solderability protection. ... because suppliers use a fairly wide of materials. Your suppl
Electronics Forum | Fri May 17 15:53:47 EDT 2002 | davef
Based on what you�ve said, comments are: * There is no reason not to expect a trace of Zn in your 85/15 Sn/Pb solderability protection, but Sn/Cu IMC are more prevalent than Zn. * Intermetallic growth and oxidation are very different materials proper
Electronics Forum | Fri Apr 19 08:46:04 EDT 2002 | geoff_goring
I would like to discover more about Zinc/Lead diffusion in the leadframes of SOIC ASICS.
Electronics Forum | Tue Sep 21 06:46:58 EDT 2004 | davef
Background on activation energy for diffusion can be found: * Materials textbooks * College lectures posted on the web. Use 'google' or someother search tool. As a guideline, the higher the activation energy, the harder is is for diffusion to occur
