Electronics Forum | Tue Sep 09 15:10:01 EDT 2003 | swagner
Has anyone had negative experiences with hasl thicknesses below .00005'' of an inch on copper? If so could you please respond with what the problems were. Thanks in advance!!!
Electronics Forum | Wed Sep 10 09:32:56 EDT 2003 | swagner
Dave F, so what kind of problems would I see if this turned into a problem?
Electronics Forum | Thu Sep 11 09:22:27 EDT 2003 | swagner
Is there any conceivable way this could cause a tombstoned device?
Electronics Forum | Thu Sep 11 16:50:18 EDT 2003 | davef
Sure it's conceivable that thin HASL can cause tombstoning. Harkening back to the ample discussion in the fine SMTnet Archives, tombstoning is caused by an imbalance in solder surface tension between the two pads of SMT component. The source of thi
Electronics Forum | Fri Sep 12 09:10:23 EDT 2003 | Norm Morikawa
Around 1989 I had this probelmm with a SMT CCA that would not solder in one area consistently. I had it cross sectioned by the bare board supplier and found that under their metallurgical microscope the thickness of this HASL bare board could not be
Electronics Forum | Fri Sep 12 13:14:33 EDT 2003 | Mark Kostinovsky
A little adition to Norm's statement: Sn-Pb intermettalic compounds do not accept solder as they are (even without being oxidized).
Electronics Forum | Tue Sep 09 18:07:18 EDT 2003 | davef
We would be very wary of allowing 50 uinches, because this will likely result in reduced shelf life due to intermetallic growth. As a guesstimate, at least 10 uinches of that 50 uinches, and maybe more, is already intermetallic when you receive the b
Electronics Forum | Wed Sep 10 12:56:09 EDT 2003 | davef
Intermetallic compounds [IMC]: * Form during the alloying process of some metals. In soldering these are Sn, Ni, Ag, Cu, Au. * Do not accept solder. * Increase in depth in logarithmic proportion to both time and temperature. [So during the solder
Electronics Forum | Mon Jun 26 23:33:20 EDT 2006 | KEN
We saw this condition over 3 years ago. It sometimes is called "champagne bubbles". The intemetalic formation is interrupted due to the micro voiding reducing mechanical strength. I discovered this on lead free test vehicles for a major computer
Electronics Forum | Thu Sep 20 07:18:42 EDT 2018 | proceng1
Has anyone else been experiencing this lately? We have had a rash of boards that come in properly vacuum sealed. We store them in the hot room until we are ready to build, and we get bubbles under the solder mask. We've had 4 different jobs, all di
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