Issue link: https://iconnect007.uberflip.com/i/488725
April 2015 • SMT Magazine 21 1 by the average SIR value from the controls in Run 2. That quotient, 1.54, then became the factor by which the average SIR values from the scenarios in Run 2 were multiplied. Figures 27 and 28 show normalized data. Because it is nor- malized data, it should be used only for relative comparison with the intent of trying to deter- mine any trends. The minimal impact that reflow profiling had on the SIR performance of a no-clean sol- der paste was quite surprising. It was anticipat- ed that a much larger difference in SIR perfor- mance would be observed as a function of the peak temperature. But even at a temperature of 225°C, a mere five degrees above the liquidus temperature of SAC305, very good (high) SIR values were achieved. This may be an indica- tion of the advancements that have been made in no-clean flux technology. It should also be noted that there were no visual differences in figure 18: controls (run 1). figure 20: Halogen-free solder paste, 245°c peak temperature soak profile (run 2). figure 19: Halogen-free solder paste, 245°c peak temperature ramp profile (run 2). figure 21: Halogen-containing solder paste, 245°c peak temperature ramp profile (run 2). ElECTriCal rEliaBiliTy OF NO-ClEaN SOlDEr paSTE Flux rESiDuES continues FeAture