Tin silver gold leadless welding material and preparation thereof

Abstract

The invention discloses a tin-silver-gold lead free solder and a preparation method thereof. The invention relates to a metal alloy, in particular to a high temperature lead free solder used in grading package and the preparation method thereof. The invention provides a novel high temperature tin-silver-gold lead free solder, the melting temperature of which can reach about 300 DEG C and which has good wettability, electrical property and welding effect and can replace the traditional Pb solder alloy of Sn-95wt percent (the melting point is 300 DEG C) and the preparation method thereof. The components and the content according to the weight percentage are as follows: 8 to 13 percent of silver, 35 to 45 percent of gold and the rest of tin. Silver, gold and tin materials are vacuum packaged in a quartz tube; and the vacuum degree in the quartz tube is ensured to be 5Pa below; then high purity argon is filled in the tube to (0.7 to 0.8) multiplied by 10<5>Pa; then the materials are put into a reaction furnace to go through melting heat treatment, then quenched in ice water after being taken out, and then vacuum packaged and annealed for at least 24 hours.

Description

technical field [0001] The invention relates to a metal alloy, in particular to a high-temperature lead-free solder material alloy for hierarchical packaging and a preparation method thereof. Background technique [0002] As the problem of environmental pollution affecting human health has become the focus of global attention, the electronic packaging industry is facing the challenge of transitioning to "green" lead-free. The prohibition of the use of certain hazardous substances in equipment (RHOS) "two decrees, from July 1, 2006, a complete ban on the import of lead-containing electronic products, the use of lead-free packaging materials is the general trend of the development of soldering materials and processes in the electronic packaging industry. [0003] Nowadays, in the semiconductor hierarchical packaging process, the high-temperature soldering materials currently used are still the traditional leaded Sn-95wt%Pb soldering material (melting point is 300 ℃) and lead-f...

AI Technical Summary

Problems solved by technology

At present, most of the lead-free solders being studied are concentrated in the medium and low temperature range, especially the SnAgCu ternary system and the SnAg binary system (5, Shi Yaowu, Lei Yongping, Xia Zhidong, etc. Development of SnAgCu-based lead-free solder technology[J] .Industry Frontiers, 2004, 4:10-16), however, most of their melting points are concentrated around 218°C, and those with a slightly higher temperature range are only around 250°C (SnSb binary alloy) (6, Chung-Yung Lin, Chiapyng Lee, Xingjun Liu and Yee-Wen Yen. Phase equilibria of the Sn-Sb-Ag ternary system and interfacial reactions at the Sn-Sb / Ag joints at 400℃ and 150℃, Intermetallics (2007), doi: 10.1016 / j. intermet.2007.10.002.), cannot meet the conditions for packaging at high temperature (300°C)

In addition, most of the high-temperature alloys under research are not Sn-based alloys, but AuSi series alloys (7, Mo Wenjian, Wang Zhifa, Jiang Guosheng, Wang Haishan, etc. Research on Au-Ag-Si new medium temperature eutectic solder. Rare metal materials and engineering, Vol34, No.3, March 2005), the cost is high, and the application is greatly limited

Images