Title :
Lifetime assessment of soft solder joints on the base of the metallurgical behaviour of Sn62Pb36Ag2
Author :
Grossmann, Gunter ; Weber, Ludger
Author_Institution :
Reliability Lab., Swiss Fed. Inst. of Technol., Zurich, Switzerland
Abstract :
The introduction of new packages as well as the ongoing miniaturisation in SMT make the evaluation of the reliability of solder joints a permanent task. Passive thermal cycling is an important test to evaluate the lifetime of solder joints. However, tin-lead solder behaves viscoplastically. Therefore it is mandatory to take the metallurgical behaviour of the solder into account when accelerated tests are designed. Two different deformation mechanisms occur, depending on the temperatures of the test as well as the temperature gradient: grain boundary sliding (GBS) and dislocation climb (DC). Therefore, one is not free in choosing the parameters of a test cycle because test parameters (temperature ramp, dwell time) have a major influence on the growth of cracks. Furthermore the stress under service conditions must be taken into account
Keywords :
dislocation climb; integrated circuit packaging; lead alloys; life testing; printed circuit manufacture; silver alloys; slip; soldering; surface mount technology; tin alloys; SMT; SnPbAg; accelerated tests; deformation mechanisms; dislocation climb; dwell time; grain boundary sliding; lifetime; lifetime assessment; metallurgical behaviour; packages; passive thermal cycling; reliability; soft solder joints; temperature gradient; temperature ramp; test parameters; Capacitive sensors; Circuit testing; Equations; Geometry; Lead; Life estimation; Performance evaluation; Soldering; Temperature dependence; Tin;
Conference_Titel :
Electronics Manufacturing Technology Symposium, 1997., Twenty-First IEEE/CPMT International
Conference_Location :
Austin, TX
Print_ISBN :
0-7803-3929-0
DOI :
10.1109/IEMT.1997.626927
