Sn-Bi-Cu-Ag-Ni-Sb low temperature lead-free solder alloy with high mechanical property

Abstract

The invention discloses a Sn-Bi-Cu-Ag-Ni-Sb low temperature lead-free solder alloy with a high mechanical property and belongs to the technical field of electronic welding. The lead-free solder alloy comprises 14-18% of Bi, 0.4-0.6% of Cu, 0.5-0.8% of Ag, 0.03-0.07% of Ni, 0.001-0.2% of Sb and the balance of Sn and inevitable impurities. In a preparation process of the Sn-Bi-Cu-Ag-Ni-Sb low temperature lead-free solder alloy with the high mechanical property, Cu, Ag, Ni and Sb are added in form of intermediate alloys. The alloy has good lubricating performance at a low temperature and the mechanical property is superior to that of Sn-Ag-Cu lead-free solder. As the percent by pass of Ag is reduced, the production cost of the lead-free solder alloy is lowered greatly and the smelting point ranges from 176 to 205 DEG C.

Description

technical field [0001] The invention relates to a Sn-Bi-Cu-Ag-Ni-Sb lead-free solder alloy with low temperature and high mechanical properties, which belongs to the technical field of electronic welding. Background technique [0002] Sn-Pb solder is the "glue" in electronic packaging technology. Sn-37Pb can provide physical connection and also realize the signal transmission function between electronic components. Due to the abundant reserves of Pb, low price, good electrical conductivity, good brazing performance, and low melting point (about 183°C), the size of components will not change too much during welding, making it widely used. With the advancement of electronic packaging materials and technology, and the increasing demand for portability and multi-functionality of electronic products, miniaturization and light weight have been paid more and more attention by everyone. With the rapid development of large-scale integrated circuit technology, semiconductor components ...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the problem of low-temperature lead-free solder in the prior art, a kind of SnBiCuAgNiSb low-temperature high-mechanical performance lead-free solder alloy is provided. The invention utilizes the phase diagram to select the temperature range of 180-210°C, and calculates the solidification process through Thermo-Calc software (See figure 1 ), determine the precipitation of each phase, determine the composition point of Sn-Bi-Cu solder, then add trace metal element Ag, and then add trace metal element Ni for compounding. The results show that the melting point of the solder alloy after compounding is 176-205°C , the structure is obviously refined under the action of Ag and Ni, and the enrichment of Bi is suppressed, which greatly improves the mechanical properties and reliability of the solder, and reduces the melting point of the Sn-Ag-Cu series lead-free solder (compared to the Sn-Ag-Cu series lead-free solder -Ag-Cu series), adding Sb to increase strength, the developed solder alloy has excellent comprehensive performance, low cost and high applicability

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