High-Speed Cyclic Bend Tests and Board-Level Drop Tests for Evaluating the Robustness of Solder Joints in Printed Circuit Board Assemblies

• Published in: Journal of electronic materials Vol. 38; no. 6; pp. 884 - 895
• Main Authors: Wong, E.H., Seah, S.K.W., Selvanayagam, C.S., Rajoo, R., van Driel, W.D., Caers, J.F.J.M., Zhao, X.J., Owens, N., Leoni, M., Tan, L.C., Lai, Y.-S., Yeh, C.-L.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-06-2009; Springer; Springer Nature B.V
• Subjects: Alloys; Applied sciences; Brazing. Soldering; Characterization and Evaluation of Materials; Chemistry and Materials Science; Electronics; Electronics and Microelectronics; Exact sciences and technology; High speed; Instrumentation; Joining, thermal cutting: metallurgical aspects; Materials; Materials Science; Metals. Metallurgy; Microelectronic fabrication (materials and surfaces technology); Optical and Electronic Materials; Printed circuit boards; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Solid State Physics; Strain rate; Temperature; solder joint; drop shock; high-speed bend test; Drop impact; drop test; PCB assembly; portable electronics; Correlation coefficient; Gold; Thermal ageing; Mechanical properties; Printed circuit board; Solder metal; Immersion; Correlation method; Thickness; Microelectronic fabrication; Soldered joint; Test method; Material testing; SN diagram; Fracture mode; Bending test; Strain rate
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-008-0610-5

This paper presents a comprehensive study of the resistance of solder joints to failure when subjected to strain rates that simulate the conditions of drop impact experienced by a portable electronic product. Two test methods are used in this study: the board-level drop-shock test (BLDST) and the board-level high-speed cyclic bend test (HSCBT). The performance of (i) 12 material combinations consisting of six solder alloys and two pad finishes, and (ii) 11 manufacturing variations covering three vendors, two finishes, three immersion gold thicknesses, and three thermal aging conditions were investigated using these two test methods. Correlations between the two test methods were performed. Quantitative correlation and sensitivity coefficients for the failure modes and the measured characteristic parameters—number of drops to failure for BLDST and number of cycles to failure for HSCBT—were evaluated. Finally, the potential of HSCBT as a test method for material selection and for bridging board-level and product-level tests was demonstrated through generation of board strain versus number of cycles to failure (S–N) curves of solder joints for six material systems, four bending frequencies, and two test temperatures.