Solder joint reliability of fine pitch surface mount technology assemblies

The reliability of fine pitch solder joint interconnection has been studied. It consists of two different fine pitch surface mount components (SMCs), namely, the EIAJ (Electronic Industry Associates of Japan) 160-pin quad flat pack (QFP) and the JEDEC (Joint Electronic Device Engineering Council) 132-pin plastic quad flat pack (PQFP). Each has a lead-spacing (from lead-center to lead-center) of approximately 0.025 in. For comparison purposes the conventional JEDEC 68-pin plastic leaded chip carrier (PLCC) and the 84-pin PLCC have also been used in the same manufacturing process. The solder joint reliability of these four SMCs has been quantified for the mechanical shock, mechanical vibration, and thermal environmental stress factors. The results show that all the solder joints under consideration will survive 10 million cycles according to the general military practice. Reliability design charts for the solder joints of these assemblies have also been developed. From these charts, the reliability of solder joints at a given statistical confidence level can be estimated.<
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