CN-120901549-B - Multicomponent tin-indium lead-free low-temperature solder and preparation method thereof

Abstract

The invention discloses a multi-component tin-indium lead-free low-temperature solder and a preparation method thereof, belonging to the technical field of microelectronic packaging. The multi-component tin-indium lead-free low-temperature solder comprises, by mass, 0.5-5% of Bi, 0.1-1.5% of Ga, and the balance of a Sn25In matrix and an unavoidable small amount of impurities. Compared with the traditional solder, the multi-component tin-indium lead-free low-temperature solder has the advantages of good heat conduction performance, good fluidity, small expansion and shrinkage rate, environmental protection, safety and the like.

Inventors

• LIAO SONGYI
• Deng Daoren
• WANG YIWU
• XIONG FEI
• MIN YONGGANG
• SHU XUGANG
• TAN WANYI

Assignees

• 广东斯特纳新材料有限公司
• 仲恺农业工程学院
• 广东工业大学

Dates

Publication Date

20260508

Application Date

20250815

Claims (6)

1. 1. A multi-component tin-indium lead-free low-temperature solder is characterized by comprising the following raw materials, by mass, 0.99-2% of Bi, 0.1-1% of Ga, and the balance of a Sn25In matrix and unavoidable impurities; The preparation method of the multi-component tin-indium lead-free low-temperature solder comprises the following steps: Preparing a Sn25In matrix; weighing Bi, ga and Sn25In matrixes according to a proportion, mixing to obtain a mixed material, adding the mixed material into a lead-free graphite heating furnace, adding an antioxidant, performing secondary heating under a nitrogen atmosphere until the materials are melted, performing secondary constant-temperature stirring, and casting In a mould to obtain the multi-component tin-indium lead-free low-temperature solder; Adding a Sn raw material into a lead-free graphite heating furnace for first heating until the material is melted, then adding an In raw material, continuously heating until the material is melted, and stirring at a first constant temperature to obtain a Sn25In matrix; the temperature of the first heating is 300-350 ℃; the specific operation steps of the first constant temperature stirring are that stirring is carried out for 30 minutes at 300-350 ℃; The temperature of the second heating is 300-350 ℃; The specific operation steps of the second constant temperature stirring are that stirring is carried out for 30 minutes at 300-350 ℃ and then heat preservation is carried out for 30 minutes.
2. 2. The multi-component tin-indium lead-free low-temperature solder according to claim 1, which is characterized by comprising the following raw materials In percentage by mass, namely 2% of Bi, 1% of Ga, and the balance of Sn25In matrix and unavoidable impurities.
3. 3. A method of preparing a multi-component indium tin-based lead-free low temperature solder according to any of claims 1-2, comprising the steps of: Preparing a Sn25In matrix; weighing Bi, ga and Sn25In matrixes according to a proportion, mixing to obtain a mixed material, adding the mixed material into a lead-free graphite heating furnace, adding an antioxidant, performing secondary heating under a nitrogen atmosphere until the materials are melted, performing secondary constant-temperature stirring, and casting In a mould to obtain the multi-component tin-indium lead-free low-temperature solder; Adding a Sn raw material into a lead-free graphite heating furnace for first heating until the material is melted, then adding an In raw material, continuously heating until the material is melted, and stirring at a first constant temperature to obtain a Sn25In matrix; the temperature of the first heating is 300-350 ℃; the specific operation steps of the first constant temperature stirring are that stirring is carried out for 30 minutes at 300-350 ℃; The temperature of the second heating is 300-350 ℃; The specific operation steps of the second constant temperature stirring are that stirring is carried out for 30 minutes at 300-350 ℃ and then heat preservation is carried out for 30 minutes.
4. 4. A method of preparation according to claim 3, wherein the antioxidant is rosin.
5. 5. A method of manufacturing according to claim 3, wherein the material of the mould is graphite.
6. 6. Use of a multi-component tin-indium lead-free low temperature solder according to any of claims 1-2 in the field of microelectronic package low temperature soldering.

Description

Multicomponent tin-indium lead-free low-temperature solder and preparation method thereof Technical Field The invention belongs to the technical field of microelectronic packaging, and particularly relates to a multi-component tin-indium lead-free low-temperature solder and a preparation method thereof. Background With the increasing demand in the electronic packaging arts for low cost and low temperature soldering processes, low temperature solders that have been developed so far include pure indium, pure tin solders. The pure indium solder has excellent performance, but the indium metal has high price and high cost, so that pure indium solder products are basically not available in the market, and the melting point of pure tin solder is about 232 ℃ but the casting temperature reaches about 350 ℃, so that the pure tin solder cannot be normally applied to a low-temperature welding environment. Lead-free low temperature solder alloys have rapidly developed in recent years due to environmental requirements and the trend toward miniaturization of electronic devices. The core advantage of the method is low-temperature welding property, so that the damage of the heat-sensitive element can be reduced, and the energy consumption is reduced. Common lead-free low temperature solder alloys are tin-bismuth and tin-indium. The tin-indium alloy has lower melting point and better wettability, and is suitable for the biomedical and aviation low-temperature packaging fields, but the relevance between the melting point and the performance of the tin-indium alloy and the ratio of indium in the alloy exists, and the high indium content in the tin-indium alloy leads to high cost. The Chinese patent CN202411113336.9 proposes a full IMC phase Sn-Bi-In-Ag-Zn high-entropy low-temperature solder for chip interconnection and a preparation method thereof, wherein the preparation method comprises the steps of (1) weighing high-purity Sn, in, bi, ag particles according to a design proportion, covering with KCl and LiCl molten eutectic fused salt with the ratio of 1.3:1 for protection, smelting Sn-In-Bi-Ag quaternary intermediate alloy, placing the low-density metal under the low-density metal In sequence, placing the high-density metal In Sn, in, bi, ag In the upper order to reduce specific gravity segregation In the smelting process, preserving heat for 2 hours at 850 ℃, fully stirring, directly casting into water for cooling, and (2) weighing high-purity Zn particles and Sn-In-Bi-Ag quaternary intermediate alloy according to the design proportion, placing the Sn-In-Bi-Ag quaternary intermediate alloy on the Zn particles for protection, casting KCl and LiCl molten eutectic fused salt In the surface of metal raw material, preserving heat for 1 hour at 500 ℃ and fully stirring, and directly casting into water for cooling to obtain the Sn-In-Bi-Ag high-Zn alloy solder. However, the In element In the solder obtained by the preparation method accounts for more than 25 percent, other noble metals are added, and the cost is still high. In view of the above, developing a low-temperature solder with lead-free environment-friendly, low cost and soldering performance comparable to that of high-indium alloy is a problem to be solved in the technical field. Disclosure of Invention Aiming at the technical problems, the invention provides a multi-component tin-indium lead-free low-temperature solder and a preparation method thereof. The method has the advantages of greatly reduced cost and environmental friendliness, and the prepared low-temperature solder has good thermal conductivity, ductility and wettability, and is suitable for low-temperature welding in the technical field of microelectronic packaging. In order to achieve the above purpose, the present invention provides the following technical solutions: The invention aims to provide a multi-component tin-indium lead-free low-temperature solder which comprises, by mass, 0.5-5% of Bi, 0.1-1.5% of Ga, and the balance of a Sn25In matrix and unavoidable small amounts of impurities. The multicomponent leadless low-temperature solder provided by the invention is mainly composed of tin-indium alloy, the melting point of In element is only 156.61 ℃, and the multicomponent leadless low-temperature solder has the characteristics of good heat and electric conductivity, good fluidity, low expansion and contraction rate and the like, and can reduce the melting point when being added into the solder alloy, and is leadless, nontoxic and environment-friendly. The solder is also added with element Bi and element Ga. The Bi element can reduce the melting point of the solder alloy, has solidification expansion characteristics, can offset the stress generated by thermal expansion and cold contraction in the welding process, and reduces the risk of cracking of welding spots. However, if the Bi content exceeds 7.5%, the filler lifting or cracking phenomenon occurs at the solder joint. The Ga element has an ultralo