Nanoindentation on SnAgCu lead-free solder and analysis

To improve the measurement accuracy of hardness and modulus results of lead-free SnAgCu from nanoindentation experiments, evaluation of the creep effect on measured result and was reported. For SnAgCu solder in this study, it was found that penetration continues with a very long time and the penetration depth could increase extra 1000 nm when the load was held constant. Thus the hardness becomes both time and load dependant. It also influences the value of modulus by affecting the upper part of the unloading curve. With optimized test method and CSM technique, Modulus of SAC387 solder alloy and all the layers in a solder joint was measured and reported. Two groups of modulus values for SAC387 were observed which were for the P-tin phase and the eutectic phase, respectively.