Reliability of BGAs and Mixed Low Temperature Solder Assemblies

• Published in: InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems pp. 1 - 8
• Main Authors: Ghaffarian, Reza, Meilunas, Michael
• Format: Conference Proceeding
• Language: English
• Published: IEEE 30.05.2023
• Subjects: ball grid array; BGA; burn-in; Electronic packaging thermal management; Failure analysis; Hybrid assembly; Industries; Isothermal aging; Lead; lead-free solder; low temperature solder; SAC305; SnBiAg; Temperature distribution; Thermomechanical processes; tin-lead solder; Transmission line matrix methods
• ISSN: 2694-2135
• DOI: 10.1109/ITherm55368.2023.10177552

This paper presents two key aspects of reliability of ball grid array (BGA) technologies: one aspect for high-reliability (HR) and the other for commercial applications. For HR, it presents the effect of isothermal aging at BGA component level to address a burn-in requirement for die screening per Military standard specification. Pull and shear behavior of BGAs with tin-lead and SAC305 solder balls were presented for fresh and burn-in conditions ( 125^{\circ}\mathrm{C} and 150^{\circ}\mathrm{C} for 240 hr). These were assembled onto PCBs and then subject to thermal cycling (TC) between 40^{\circ}\mathrm{C} and 105^{\circ}\mathrm{C} . Cycles-to-failures (CTFs) in Weibull plots were presented for the SnPb CABGA208 assemblies with micro-sectioned images, The commercial aspect covered low temperature solder ball and solder paste for assembling BGAs and other components. Two types of low temperature BiSn alloys, either Cu/Ni or Ag additives and with 139^{\circ}\mathrm{C}/174^{\circ}\mathrm{C} solidus/liquidus temperatures, were evaluated. The mixed hybrid configuration utilized SAC305 BGAs using the SnBiAg solder paste. The low temperature assemblies were subjected to two TCs (-40^{\circ}\mathrm{C}/105^{\circ}\mathrm{C} and 0^{\circ}\mathrm{C}/105^{\circ}\mathrm{C}) . CTF results are presented for CABGA208 with failure analysis by X -sectional evaluation.