State of the Art of Lead-Free Solder Joint Reliability

Abstract The state of the art of lead-free solder joint reliability is investigated in this study. Emphasis is placed on the design for reliability (DFR) and reliability testing and data analysis. For DFR: (a) the Norton power creep constitutive equations and examples for Au20Sn, Sn58Bi, Sn3.8Ag0.7Cu, and Sn3.8Ag0.7Cu0.03Ce, (b) the Wises two power creep constitutive equations and examples for Sn3.5Ag and Sn4Ag0.5Cu, (c) the Garofalo hyperbolic sine creep constitutive equations and examples for Sn3.5Ag, Sn3Ag0.5Cu, Sn3.9Ag0.6Cu, Sn3.8Ag0.7Cu, Sn3.5Ag0.5Cu, and Sn3.5Ag0.75Cu, Sn4Ag0.5Cu, Sn(3.5-3.9)Ag(0.5-0.8)Cu, 100In, Sn52In, Sn3.8Ag0.7Cu0.03Ce, and Au20Sn, and (d) the Anand viscoplasticity constitutive equations and examples for Sn3.5Ag, Sn3Ag0.5Cu, Sn3.8Ag0.7Cu, Sn3.8Ag0.7CuCe, Sn3.8Ag0.7CuAl, Au20Sn, Sn3.5Ag with temperature and strain rate-dependent parameters, and Sn1Ag0.5Cu, Sn2Ag0.5Cu, Sn3Ag0.5Cu, and Sn4Ag0.5Cu after extreme aging will be discussed. For reliability testing and data analysis: (a) the Weibull and lognormal life distributions for lead-free solder joints under thermal-cycling and drop tests, (b) the true Weibull slope, true characteristic life, and true mean life, and (c) the linear acceleration factors for various lead-free solder alloys based on: (i) frequency and maximum temperature, (ii) dwell time and maximum temperature, and (iii) frequency and mean temperature will be presented. Some recommendations will also be provided.