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Reply To: | (Leadfree Electronics Assembly Forum) |
Date: | Fri, 18 Nov 2005 14:36:39 +0100 |
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We published a characterisation study in Soldering and Surface Mount Technology Vol17 about LF BGAs soldered with SnPb. Well I stated that from the metallurgy side i didn't see any reason why this shouldn't work. Looking at the presentation of David (beautiful pictures by the way) I am glad to see that the rupture due to thermal cycling is not along the SnPb / LF interface. There is a rupture along the pad on the PCB. Well, to be provocative, somewhere the joint has to let go. Usually at the weakest point which seems to be the solder/pad interface. Does a LF BGA soldered with LF solder withstand the 2000 cycles that are mentioned as a minimum ?
Guenter
EMPA
Swiss Federal Laboratories for Materials Testing and Research
Centre for Reliability
Guenter Grossmann, Senior Engineer
8600 Duebendorf
Switzerland
Phone: xx41 1 823 4279
Fax : xx41 1 823 4054
mail: [log in to unmask]
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