Kuan

As Werner already mentioned, the metallurgy of your solder joint will change significant during the annealing. However, it depends on the conditions of use whether this changes ( Thicker intermetallics, enhanced Pb concentration at the interfaces, growth of Pb phases, secondary segregation in the bulk etc. ) are of significance for the reliability of your assembly. As much as I remember, Werner, didn't you do some work on tested joints with and without annealing in order to show that annealing ahead of thermal cycling tests is important?

Best regards

Guenter

Guenter Grossmann
Swiss Federal Institute for Materials Testing and Research EMPA
Centre for Reliability
8600 Duebendorf
Switzerland

Phone: xx41 1 823 4279
Fax :      xx41 1823 4054
mail:     [log in to unmask]

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