iNEMI Pb-Free Alloy Characterization Project Report: Part II - Thermal Fatigue Results For Two Common Temperature Cycles
Authors: Richard Parker, et al. Date Published: 10/14/2012
Abstract: The Pb-Free Alloy Characterization Program sponsored by International Electronics Manufacturing Initiative (iNEMI) is conducting an extensive investigation using accelerated temperature cycling (ATC) to evaluate ball grid array (BGA) thermal fatigue performance of 12 commercial or developmental Sn based Pb-free solder alloys. This paper presents the initial findings from a specific subset of the temperature cycling test matrix. The focus is on comparing alloy performance for two of the most commonly specified temperature cycles, 0 to 100 °C and -40 to 125 °C. These two cycles have different temperature extremes and cyclic temperature ranges (referred to as "delta" T) but identical 10 minute hot and cold dwell times. The failure data are reported as characteristic life "eta" (number of cycles to 63.2% failure) and slope "beta" from a two-parameter Weibull analysis. The ATC data and failure analyses are discussed in terms of the relationship to alloy composition and to the initial microstructures as well as the microstructures as they evolve during temperature cycling.