A COLLABORATIVE INDUSTRIAL CONSORTIA PROGRAM FOR CHARACTERIZING THERMAL FATIGUE RELIABILITY OF THIRD GENERATION PB-FREE ALLOYS Richard Coyle 1 , Richard Parker 2 , Keith Howell 3 , Dave Hillman 4 , Joe Smetana 5 , Glen Thomas 6 , Stuart Longgood 7 , Michael Osterman 8 , Eric Lundeen 9 , Polina Snugovsky 10 , Julie Silk 11 , Andre Kleyner 7 , Keith Sweatman 3 , Rafael Padilla 12 , Tomoyasu Yoshikawa 12 , Jasbir Bath 13 , Mitch Holtzer 14 , Hongwen Zhang 6 , Jerome Noiray 15 , Frederic Duondel 15 , Raiyo Aspandiar 16 , and Jim Wilcox 17 1 Nokia Bell Labs, Murray Hill, NJ, USA 2 iNEMI, Tipton, IN, USA 3 Nihon Superior Co., Ltd., Osaka, Japan 4 Rockwell Collins, IA, USA 5 Nokia, Plano, TX USA 6 Indium Corp., Utica, NY,USA 7 Delphi, Kokomo, IN, USA 8 CALCE, College Park, MD, USA 9 i3 Electronics, Endicott, NY, USA 10 Celestica, Inc., Toronto, ON, Canada 11 Keysight Technologies, Santa Rosa, CA, USA 12 Senju Metal Industry Co., Tokyo, Japan 13 Bath & Associates Consultancy, Fremont, CA, USA 14 Alpha Assembly Solutions, South Plainfield, NJ, USA 15 Sagem, Paris, France 16 Intel Corporation, Hillsboro, OR, USA 17 Universal Instruments Corporation, Conklin, NY, USA richard.coyle@nokia-bell-labs.com; rddlparker@gmail.com ABSTRACT Development of the first generation of current commercial Pb-free solder alloys was based on, high Ag content, near- eutectic Sn-Ag-Cu (SAC) compositions. Subsequently, second generation, lower Ag alloys were developed to address the shortcomings of near-eutectic SAC, particularly poor mechanical shock performance. The development of third generation Pb-free solder alloys is proceeding along two prominent paths. In one case, high-Ag content alloys are being modified with various major alloying additions to improve thermal fatigue performance in aggressive use environments and increase resistance to damage from high strain rate mechanical loading. In the other case, alloys with Ag content lower than SAC305 are being developed to address needs for better drop/shock resistance, lower processing (melting) temperature, and lower cost. This paper describes the planning and progress of an experimental program for evaluating the thermal fatigue performance of a number of third generation alternative Pb- free solder alloys. The program is being developed and executed through a collaboration of several major industrial consortia that includes membership from high reliability end users, solder suppliers, and electronic contract manufacturers. Key words: Lead-free alloys, alternative alloys, low and high silver alloys, third generation Pb-free alloys, microalloying, thermal fatigue reliability INTRODUCTION In the decade since the implementation of the RoHS Directive [1], there have been a number of significant innovations in Pb-free solder alloy formulations. Alloy development continues to be driven primarily by experience gathered through volume manufacturing and increased deployment of a variety of Pb-free products of increasing complexity. This experience has resulted in an increased number of Pb-free solder alloy choices beyond the first generation near-eutectic Sn-Ag-Cu (SAC) alloys that were established initially as replacements for eutectic SnPb [2]. Second generation, lower Ag alloys have been developed and introduced to address the shortcomings of the first generation near-eutectic SAC, such as poor mechanical shock performance, higher cost, and a variety of technical Proceedings of SMTA International, Sep. 25 - 29, 2016, Rosemont, IL, USA Page 188 As originally published in the SMTA Proceedings