Title :
Investigation of thin small outline package (TSOP) solder joint crack after accelerated thermal cycling testing
Author :
Lu, L.N. ; Huang, H.Z. ; Wu, B.Y. ; Zhou, Q. ; Su, X.X. ; Cai, M.
Author_Institution :
Sch. of Mechatron. Eng., Univ. of Electron. Sci. & Technol. of China Chengdu, Chengdu, China
Abstract :
Solder joint crack is a common failure mode of printed circuit board assembly (PCBA) for electronic products. In order to investigate the crack behavior of fine-pitch SMT solder joints, accelerated thermal cycling (ATC) up to 1500 cycles was performed on advanced PCBAs with low-profile thin small outline package (TSOP). The functional examination result shows that the failure rate of TSOP solder joint open after ATC is 2.5%, 7.5% and 27.5% after 1000, 1250 and 1500 cycles, respectively. Optical inspection by microscopy demonstrates obvious solder joint cracks at many locations. Cross sectional study has confirmed serious crack in the bulk solder, resulting in electrical failures. Also, microstructural information has been obtained by metallurgical analysis with the aid of Scanning electron microscopy (SEM). In addition, finite element analysis (FEA) was performed to simulate the thermal-mechanical stress in solder joints under ATC. Based on the modelling, the fatigue life of solder layer was calculated. Both experimental study and modelling confirmed that solder fatigue crack upon concentrated stress during ATC is a major contributor to the open failure of TSOP solder joints.
Keywords :
crack detection; failure analysis; fine-pitch technology; finite element analysis; life testing; optical microscopy; printed circuit manufacture; scanning electron microscopy; soldering; surface mount technology; thermal management (packaging); thermal stresses; FEA; SEM; accelerated thermal cycling testing; electrical failure; electronic products; fatigue life; fine-pitch SMT solder joints; finite element analysis; metallurgical analysis; microstructural information; optical inspection; optical microscopy; printed circuit board assembly; scanning electron microscopy; solder joint crack; thermal-mechanical stress; thin small outline package; Assembly; Circuit testing; Electronic packaging thermal management; Fatigue; Life estimation; Optical microscopy; Printed circuits; Scanning electron microscopy; Soldering; Thermal stresses;
Conference_Titel :
Electronic Packaging Technology & High Density Packaging, 2009. ICEPT-HDP '09. International Conference on
Conference_Location :
Beijing
Print_ISBN :
978-1-4244-4658-2
Electronic_ISBN :
978-1-4244-4659-9
DOI :
10.1109/ICEPT.2009.5270557
