Solder joint fatigue in a surface-mount assembly subjected to mechanical loading

A mechanical approach employing cyclic twisting deformation to a surface mount assembly is examined as an alternative to temperature cycling for evaluating solder joints fatigue performance. This highly accelerated test is aimed at reducing solder joint reliability testing cycle time. In this study, the mechanics of solder joints in a surface mount assembly subjected to cyclic twisting deformation on the PCB is investigated. For this purpose, a test package with 24 by 24 peripheral-array solder joints is modeled using the finite element method. Unified inelastic strain theory defines the strain-rate-dependent plastic stress-strain response of the 60Sn-40Pb solder. Cyclic twisting deformation in the range of plusmn1deg at a rate of 120 seconds per cycle was applied to the PCB assembly sub-model. The calculated stress and strain distributions in the critical solder joint are compared with those predicted for temperature cycling and accelerated temperature cycling tests. Results showed that the accumulated inelastic strain concentrates in a small region of the critical solder joint near the component side for temperature cycling and near the pad side for cyclic twisting cycles. The rate of inelastic strain accumulation per fatigue cycle in the solder joint for both thermal cycling (TC1) and mechanical twisting (MT1) tests are similar. Thus mechanical twisting test imparts similar characteristics in terms of the shear strain range to temperature cycling tests. Low cycle fatigue is dominated by localized shear effect as reflected in the largest shear strain range of the hysteresis loops. The Coffin-Manson strain-based model yielded more conservative prediction of fatigue lives of solder joints when compared to energy-based approach

[1]  R. Ghaffarian.  Accelerated thermal and mechanical testing of CSP assemblies , 2000 .

[2]  Wei Zhou,et al.  A New Creep Constitutive Model for Eutectic Solder Alloy , 2002 .

[3]  H. Reichl,et al.  An efficient approach to predict solder fatigue life and its application to SM- and area array components , 1997, 1997 Proceedings 47th Electronic Components and Technology Conference.

[4]  Sidharth,et al.  Board level solder reliability versus ramp rate and dwell time during temperature cycling , 2003 .

[5]  Doug Abbott,et al.  Materials characterization of the effect of mechanical bending on area array package interconnects , 2003, Microelectron. Reliab..

[6]  L. Anand.  Constitutive equations for hot-working of metals , 1985 .

[7]  I. K. Hui,et al.  Fatigue life estimation of surface mount solder joints , 1996 .

[8]  J. Lau,et al.  Solder Joint Reliability of BGA, CSP, Flip Chip, and Fine Pitch SMT Assemblies , 1996 .

[9]  M. Amagai,et al.  Chip scale package (CSP) solder joint reliability and modeling , 1998, 2nd 1998 IEMT/IMC Symposium (IEEE Cat. No.98EX225).

[10]  S. Manson,et al.  Thermal Stress and Low-Cycle Fatigue , 2020, Encyclopedia of Continuum Mechanics.

[11]  Reza Ghaffarian,et al.  Accelerated Thermal Cycling and Failure Mechanisms for BGA and CSP Assemblies , 2000 .

[12]  H. Solomon.  Fatigue of 60/40 Solder , 1986 .

[13]  X.Q. Shi,et al.  Sensitivity study of temperature and strain rate dependent properties on solder joint fatigue life , 1998, Proceedings of 2nd Electronics Packaging Technology Conference (Cat. No.98EX235).

[14]  K. H. Ang,et al.  Methodology for a highly accelerated solder joint reliability test , 2000, Proceedings of 3rd Electronics Packaging Technology Conference (EPTC 2000) (Cat. No.00EX456).

[15]  T. Reinikainen,et al.  Absolute and relative fatigue life prediction methodology for virtual qualification and design enhancement of lead-free BGA , 2005, Proceedings Electronic Components and Technology, 2005. ECTC '05..

[16]  N. Sottos,et al.  Mechanical characterization of plastic ball grid array package flexure using moire interferometry , 2000 .

[17]  Y. Koh.  A unified constitutive model for solder materials , 2004 .

[18]  A. Yeo,et al.  Flip chip solder joint fatigue life model investigation , 2002, 4th Electronics Packaging Technology Conference, 2002..

[19]  Robert Darveaux,et al.  Solder Joint Fatigue Life Model , 1997 .

[20]  J. H. Lau,et al.  Solder joint reliability of flip chip and plastic ball grid array assemblies under thermal, mechanical, and vibrational conditions , 1996 .

[21]  Santosh Shetty,et al.  Three- and Four-Point Bend Testing for Electronic Packages , 2003 .

[22]  K. Ohguchi,et al.  Viscoplastic Deformation of 40 Pb/60Sn Solder Alloys—Experiments and Constitutive Modeling , 2001 .

[23]  B.A. Zahn,et al.  Solder joint fatigue life model methodology for 63Sn37Pb and 95.5Sn4Ag0.5Cu materials , 2003, 53rd Electronic Components and Technology Conference, 2003. Proceedings..