To make a soldering process successful it is necessary that the components to be joined by the solder can withstand the soldering treatment without to be damaged. To realize a good solder quality it is necessary that the components to be joined have a good wettability with solder. This is called the surface solderability.
Furthermore the design of the joint must be such that the solder can and will stay liquid during the soldering process and will not cool down below its melting point during the joint formation. This is called the thermal solderability. Only when the demands for surface solderability and thermal solderability are met, we are able to create joints where the solder is able to fill the holes completely.
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