Abstract: A package substrate includes die solder pads and pin solder fillets. The pin solder fillets might comprise between approximately 90 wt % to approximately 99 wt % tin and approximately 10 wt % to 1 wt % antimony. The die solder pads might comprise between approximately 4 wt % to approximately 8 wt % bismuth, approximately 2 wt % to approximately 4 wt % silver, approximately 0 wt % to approximately 0.7 wt % copper, and approximately 87 wt % to approximately 92 wt % tin. The die solder pads might comprise between approximately 7 wt % to approximately 20 wt % indium, between approximately 2 wt % to approximately 4.5 wt % silver, between approximately 0 wt % to approximately 0.7 wt % copper, between approximately 0 wt % to approximately 0.5 wt % antimony, and between approximately 74.3 wt % to approximately 90 wt % tin.