Low-temperature lead-free solder alloy

Abstract

The invention discloses a low-temperature lead-free solder alloy, and belongs to the technical field of electronic welding. The low-temperature lead-free solder alloy comprises, by weight percentage,20-50% of Bi, 0.5-10% of Sb, 0.5-10% of In, 0-0.20% of Ge and 0-0.11% of P; two or more than two types of 0-0.2% of Ni, 0-0.2% of Co, 0-0.11% of Ga, 0-0.2% of Si, 0-0.5% of Al and 0-0.5% of Zn; and the balance of Sn and inevitable impurities. According to the low-temperature lead-free solder alloy, multi-element alloy elements such as the Sb, the In, the Ni, the Co, the Ge and the like are added so that the mechanical performance of the solder alloy can be obviously changed; and in formed welding spots and interfaces, the multi-element alloy elements in the dispersed distribution block enrichment of the Bi and prevent generation of rich Bi phases, so that damage of the hard and brittle rich Bi phases to the mechanical property of welding joints is reduced, and the welding performance of the solder alloy is improved.

Description

technical field [0001] The invention relates to a low-temperature lead-free solder alloy, which belongs to the technical field of electronic welding. Background technique [0002] Electronic waste pollutes the environment a lot. In order to protect the environment, lead-free solder has been used to replace traditional lead solder in the field of packaging and soldering of electronic components. At present, the lead-free solder alloys that are widely used are mainly SnCu-based and SnAgCu-based alloy solders. Compared with tin-lead eutectic solders, the melting points of SnCu-based and SnAgCu-based alloy solders are about 30°C higher, and the soldering process temperature is higher. However, with the continuous advancement of Moore's Law, chips are becoming more and more highly integrated and thinner, which makes chips more prone to warping during electronic assembly, resulting in defects such as pillows, bridges, and poor wetting. In order to solve this problem, it is necess...

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Problems solved by technology

[0004] Aiming at the problems existing in the low-temperature lead-free solder in the prior art, the present invention provides a low-temperature lead-free solder alloy, which improves the enrichment of Bi in the solder alloy through the composite addition of various trace elements, thereby reducing the brittleness of the solder joint, At the same time,

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