SnBiAgSbIn low-temperature lead-free solder alloy

Abstract

The invention discloses a SnBiAgSbIn low-temperature lead-free solder alloy, belonging to the technical field of low-temperature solder alloys. Low-temperature lead-free solder is prepared from the following ingredients in percentage by weight: 30-60% of Bi, 0-3.5% of Ag, 0.1-3% of Sb, 0-3.0% of In, 0-0.11% of Ge, 0-0.11% of P, more than two kinds of rare earth elements, the balance of Sn and unavoidable impurities. The alloy can be used for inhibiting the segregation of a Bi element, improving the mechanical property of welding spots, and solving the problems that in the process of using binary SnBi solder at present, the welding spots can generate cavities easily, the mechanical performance is poor, and the welding spots are easy to peel off and the like.

Description

technical field [0001] The invention relates to a SnBiAgSbIn low-temperature lead-free solder alloy, belonging to the technical field of low-temperature solder alloys. Background technique [0002] Since electronic solder has become lead-free, SnCu-based and SnAgCu-based solder alloys have been widely used, and these widely used solder alloys have higher melting points. However, with the continuous advancement of Moore's Law, chips are developing towards high integration and thinning. When soldering with existing soldering processes, process defects such as warping, pillows, and bridges are prone to occur. Moreover, due to the high soldering temperature, the thermal failure rate of the chip is relatively high. In response to the above problems, relevant companies such as the solder industry are currently actively developing low-temperature lead-free solder alloys. Current low-temperature solders include SnBi-based, SnZn-based, and SnIn-based solders. Among them, SnZn has p...

AI Technical Summary

Problems solved by technology

In can improve the wettability of solder, but In is a scattered metal, the global resource reserves are extremely low, the price is high, and it does not have the prospect of large-scale use. It can only be added as a trace element.

The SnBi low-temperature lead-free solder alloy is widely used. The addition of Bi can effectively reduce the melting point of the solder, but the SnBi solder alloy is easy to segregate, resulting in poor soldering performance and high solder joint brittleness, such as the melting point of eutectic solder Sn58Bi The eutectic phase SnBi is in the form of flakes at a moderate cooling rate; at a slow cooling rate, the grains are larger, and the cracks of the brazed joint generally expand along the grain boundary; and the recrystallization of the brazed joint will cause Volume expansion, which increases the embrittlement of the alloy

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