SnBiZn series low-temperature lead-free solder and preparation method thereof

A technology of lead-free solder and lead-free solder alloy, applied in welding equipment, welding/cutting media/materials, manufacturing tools, etc., can solve problems such as deformation, achieve improved oxidation resistance, fine grain size, and improved wettability Effect

Active Publication Date: 2016-12-07
BEIJING COMPO ADVANCED TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At the same time, the SnBiZn-X solder alloy can solve a series of welding quality problems caused by warping, deformation and pillows of the welded parts such as microchips, BGAs, and CSPs caused by high temperature during the welding process.

Method used

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  • SnBiZn series low-temperature lead-free solder and preparation method thereof
  • SnBiZn series low-temperature lead-free solder and preparation method thereof
  • SnBiZn series low-temperature lead-free solder and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0030] A lead-free solder alloy used in the field of low-temperature soldering. In terms of weight percentage, the lead-free solder alloy powder contains: Bi 49%, Zn 2.0%, and the rest is Sn. The lead-free solder alloy has a ternary eutectic structure, The melting point of the alloy is 133.8-137.5. The method for preparing the lead-free solder alloy comprises the following steps:

[0031] 1) Add metal Sn and Zn with a purity of 99.99wt.% into the vacuum melting furnace according to a certain alloy ratio, and vacuumize to 1×10 -1 Pa, filled with nitrogen; heat the alloy to 500-550 ° C to melt, and at the same time, add electromagnetic stirring to make the alloy composition uniform, and then vacuum cast to prepare the SnZn9 master alloy;

[0032] 2) Melting the prepared Sn-Zn master alloy, Sn, and Bi in a melting furnace according to the alloy ratio. Cover the surface of the alloy with an anti-oxidation solvent (rosin or KCl-LiCl molten salt), heat the alloy to 200°C, keep it ...

Embodiment 2

[0035] A lead-free solder alloy used in the field of low-temperature soldering, the lead-free solder alloy powder contains: Bi 56.2%, Zn 2.1%, the rest is Sn in weight percent, the melting point of the lead-free solder alloy is 134.5-142.3°C. The method for preparing the lead-free solder alloy is the same as that in Example 1 except that the alloy ratio is different.

Embodiment 3

[0037] A lead-free solder alloy used in the field of low-temperature soldering, the lead-free solder alloy powder contains: Bi 49%, Zn 2.0%, Ce 0.003%, Al 0.03%, the rest is Sn, the lead-free solder The alloy is a near-eutectic structure with a melting point of 132.8-136.0°C. The method for preparing the lead-free solder alloy comprises the following steps:

[0038] 1) Add metals Sn and Zn, Sn and Ce, Sn and Al with a purity of 99.99wt.% into the vacuum melting furnace according to a certain alloy ratio, and vacuumize to 1×10 -2 Pa, after being filled with nitrogen; the alloys were heated to 500-550°C, 690-780°C, and 400-500°C to melt, and electromagnetic stirring was added at the same time to make the alloy composition uniform, and then vacuum casting to prepare SnZn9, SnCe10, SnAl5 master alloy;

[0039] 2) Melting the prepared Sn-Zn, Sn-Ce, Sn-Al master alloys and metals Sn and Bi in a melting furnace according to the alloy ratio. Cover the surface of the alloy with an a...

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Abstract

The invention discloses SnBiZn series low-temperature lead-free solder and a preparation method thereof and belongs to the technical field of low-temperature soft solder. The lead-free solder is composed of, by weight, 45.5-56.2% of Bi, 1.7-2.4% of Zn, and the balance Sn, wherein the weight percentage of Bi and Zn meets the relational expression b=0.0123a<2>-1.27a+34.652+c, a is the weight percentage of Bi, b is the weight percentage of Zn, and the value range of c is -0.2<=c<=0.2. The invention further discloses the preparation method of the lead-free solder. Solder alloy is eutectic or near-eutectic structures, the melting point is low, and the SnBiZn series low-temperature lead-free solder has excellent mechanical properties and solder joint reliability and is suitable for the field of low-temperature of soft solder.

Description

technical field [0001] The invention relates to a SnBiZn-based low-temperature lead-free solder and a preparation method thereof, in particular to a SnBiZn-X lead-free solder alloy used in the field of low-temperature soldering and a preparation method thereof, belonging to the technical field of low-temperature soft solder. Background technique [0002] With the rapid development of lead-free electronic products and the direction of light, thin and high-function, the lead-free solder SnAgCu series (especially SAC305) mainly used in SMT at present, due to the high melting point of solder (200 ℃ ~ 230 ℃), reflow The new thin and light chips in the soldering process are very sensitive to temperature, and the chips are easily damaged. Therefore, the low-temperature solder (including but not limited to solder paste, tin wire, tin bar) market has an urgent demand for low-temperature solder. In the prior art, SnBi-based solder is often used in low-temperature soldering, especially...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K35/26
CPCB23K35/0222B23K35/264
Inventor 贺会军刘希学孙彦斌王志刚胡强祝志华徐蕾李晓强李昕
Owner BEIJING COMPO ADVANCED TECH
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