The key to achieving good reliability and requisite service lifetimes in modern electronic devices has long been associated with the quality of the solder joints used in assembling components onto substrates. Originally, the electronics industry used leaded components with through hole mounting and solder joints that were much larger than are found today. The solders were also typically made of tin and lead, in compositions that had both modest melting points and good mechanical properties.
However, progress in the electronics industry has always been characterised by ever greater levels of integration and miniaturisation that have seen the move from leaded components to the use of surface mount technology and increasing numbers of connections being required to fit into smaller and smaller areas on a circuit board or substrate. As a result, the actual volumes of solder used to form the individual solder joints has been significantly diminished, e.g. in area array packaging.
“The actual volumes of solder used to form the individual solder joints has been significantly diminished, e.g. in area array packaging.”
“For some applications, solder joint reliability can still be a very significant factor that needs to be addressed.”