Optimization of multicomponent SnBiInSbx low-temperature solder with varied Sb contents

The drive toward miniaturization, functionalization, and environmental conservation in electronic devices has increased the demand for low-temperature solder in 3D packaging processes. The influence of Sb incorporation on the structure and properties of SnBiIn solder at an equal molar ratio is investigated. It is demonstrated that Sb incorporation facilitates the formation of SnIn phase and induces the precipitation of spherical Bi particles. Furthermore, the concentration of Sb directly affects the morphologies of both Bi and SbIn phases. The amount of Sb also directly impacts the morphologies of Bi and SbIn phases, resulting in distinct solid solution and second-phase strengthening effects. These effects consequently alter the properties of the solder. This phenomenon arises because Sb hinders atomic diffusion within the joint, leading to the formation of thin Cu₆(Sn, In)₅ intermetallic compounds. It can be reasonably inferred that lead-free low-temperature solders, based on high-entropy alloy multicomponent compositions and engineered via elemental modulation, show promise for successful applications in electronic packaging.