The invention relates to Sn-Bi-In-Ag-Zn high-reliability high-entropy
alloy low-temperature solder for advanced packaging and a preparation method of the Sn-Bi-In-Ag-Zn high-reliability high-entropy
alloy low-temperature solder, and belongs to the technical field of
electronic packaging materials. The solder comprises, by atomic percent, 25%-35% of
tin, 25%-35% of
bismuth, 25%-35% of
indium, 5% of silver and 5%-10% of
zinc, and preparation of the solder is achieved in an induction melting mode. Main phases of the Sn-In-Bi-Ag-Zn high-reliability high-entropy
alloy low-temperature solder for
electronic packaging are the
tin-based
solid solution and the
indium bismuth phase,
bismuth and
indium atoms are subjected to high
solid solution in the
tin-based
solid solution, and
solid solution strengthening of the solder is promoted. The
melting point is only 80-90 DEG C, and the warping problem caused by CET mismatching can be effectively reduced due to the extremely
low melting point. The low-temperature wettability is good, and the
wetting angle is smaller than or equal to 33 degrees when the
copper substrate is wetted at 120 DEG C. Meanwhile, inhibition of interface IMC rapid growth can be achieved without a
diffusion barrier layer, a thin IMC layer can still be kept under the conditions of long-time and multiple times of
backflow, the volume ratio of the IMC in a micro
welding spot can be remarkably reduced, the influence of the IMC on the
mechanical property and reliability of the
welding spot can be reduced, good
mechanical property can still be kept after long-time and multiple times of
backflow, and the service life of the
welding spot can be prolonged. The method is suitable for advanced packaging such as flexible packaging and 3D IC packaging which require low packaging temperature or high
thermal reliability.