A series of low-silver lead-free solder for electronic package soldering and preparation method thereof

A lead-free solder, electronic packaging technology, used in welding equipment, welding/cutting media/materials, welding media, etc., can solve the problems of poor wettability and mechanical properties, high silver content, and achieve good wettability, The effect of low rate of Cu dissolution and high tensile strength

Active Publication Date: 2015-08-26
深圳市同方电子新材料有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The purpose of the present invention is to overcome the technical problems of relatively high silver content, poor wettability and mechanical properties in the existing low-silver lead-free solder, and provide a series of low-silver lead-free solder for electronic package soldering and its Preparation method, thereby reducing the production cost of silver-containing solder, improving the wettability and mechanical properties of solder, and further reducing the corrosion of solder to Cu

Method used

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  • A series of low-silver lead-free solder for electronic package soldering and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] The composition and mass percentage of a series of low-silver lead-free solder for electronic packaging soft soldering are: Ag: 0.5%, Cu: 0.7%, Ge: 0.1%, Si: 0.05%, Pr: 0.25%, Sn : 98.4%.

[0036] The Sn-Pr master alloy containing 5% Pr and the Sn-Si containing 1% Si were prepared in a vacuum melting furnace.

[0037] Inter-alloy; heat the mixed salt of 195g of KCl and 150g of LiCl at 500℃ to melt, then cover it on the surface of 887gSn, keep it for 30 minutes; heat the molten tin to 600℃, add 50gSn-Si intermediate alloy, uniform Stir and hold for 30 minutes to obtain a molten Sn-Si alloy; then cool the molten Sn-Si alloy to 500°C, add 50g of Sn-Pr master alloy, and stir uniformly for 40 minutes to obtain a molten Sn-Si-Pr alloy; Cool down the molten Sn-Si-Pr alloy to 400°C, add 5gAg, 7gCu and 1gGe, stir evenly, keep for 120 minutes, get the molten Sn-Ag-Cu-Si-Pr-Ge alloy, stand it out of the furnace, and cast it on the stainless steel In the mold, the mixed salt on the su...

Embodiment 2

[0039] The composition and mass percentage of a series of low-silver lead-free solder for electronic packaging soft soldering are: Ag: 1.0%, Cu: 0.01%, Ge: 0.002%, Si: 0.1%, Pr: 0.5%, Sn : 98.388%.

[0040] The Sn-Pr master alloy containing 5% Pr and the Sn-Si containing 1% Si were prepared in a vacuum melting furnace.

[0041] Inter-alloy; heat the mixed salt of 195g of KCl and 150g of LiCl at 550℃ to melt it, then cover it on the surface of 789.88gSn, keep it for 40 minutes; heat the molten tin to 700℃, add 100g of Sn-Si intermediate alloy , Stir uniformly and keep for 40 minutes to obtain a molten Sn-Si alloy; then cool the molten Sn-Si alloy to 600°C, add 100g of Sn-Pr master alloy, and stir uniformly for 30 minutes to obtain a molten Sn-Si-Pr alloy ; Then the molten Sn-Si-Pr alloy is cooled to 500 ℃, 10gAg, 0.1gCu and 0.02gGe are added, stir evenly, and hold for 60 minutes to obtain the molten Sn-Ag-Cu-Si-Pr-Ge alloy , Pouring in a stainless steel mold, and removing the mixe...

Embodiment 3

[0043] The composition and mass percentage of a series of low-silver lead-free solder for electronic packaging soft soldering are: Ag: 0.01%, Cu: 1.0%, Ge: 0.2%, Si: 0.001%, Pr: 0.001%, Sn : 98.788%.

[0044] The Sn-Pr master alloy containing 5% Pr and the Sn-Si containing 1% Si were prepared in a vacuum melting furnace.

[0045] Inter-alloy; heat and melt the mixed salt of 195g KCl and 150g LiCl at 520℃, then cover it on the surface of 986.7gSn, keep it for 35 minutes; heat the molten tin to 650℃, add 1gSn-Si intermediate alloy , Stir uniformly and keep for 35 minutes to obtain a molten Sn-Si alloy; then cool the molten Sn-Si alloy to 550°C, add 0.2g Sn-Pr master alloy, and stir evenly for 35 minutes to obtain a molten Sn-Si-Pr Alloy; then cool the molten Sn-Si-Pr alloy to 450°C, add 0.1gAg, 10gCu and 2gGe, stir evenly, keep for 100 minutes to obtain the molten Sn-Ag-Cu-Si-Pr-Ge alloy , Pouring in a stainless steel mold, and removing the mixed salt on the surface after solidific...

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Abstract

The invention relates to serial low-silver and lead-free solder for electronic packaging soft soldering and a preparation method thereof. The solder comprises Ag, Cu, Si, Pr, Ge and Sn, wherein the Ag content is only 0.01-1.0%. The preparation method of the solder comprises the following steps of: firstly, preparing an Sn-Pr intermediate alloy and an Sn-Si intermediate alloy; after heating and melting mixed salt of KCl and LiCl, covering the mixed salt of the KCl and the LiCl on the liquid surface of rest tin in a smelting furnace, and preserving the temperature; raising the temperature of the fused solder to 600-700 DEG C, adding the Sn-Si intermediate alloy, stirring, and preserving the temperature; lowering the temperature of the fused solder to 500-600 DEG C, and adding the Sn-Pr intermediate alloy; lowering the fused solder to 400-500 DEG C, adding the Ag, the Cu and the Ge, uniformly stirring, and preserving the temperature; and finally, pouring the fused solder into fixed molds, and carrying out cooling forming to prepare the solder. The serial low-silver and lead-free solder and the preparation method have the advantages and effects of low cost, good wettability, good weldability, high tensile strength, low Cu dissolving speed and the like.

Description

technical field [0001] The invention relates to the technical field of electronic package soldering of electronic and electrical products, in particular to a series of low-silver lead-free solder for electronic package soldering and a preparation method thereof. Background technique [0002] In recent years, due to the increasingly serious pollution and harm brought by lead and its compounds to the human ecological environment and the enhancement of human environmental protection awareness, the call for banning the use of Pb is increasing worldwide. The concept of lead-free electronic packaging has penetrated into countries all over the world and set off A research boom of lead-free solder. [0003] At present, the research work on lead-free solder has been developed rapidly, and Sn-Ag-Cu lead-free solder is recognized as the most ideal lead solder due to its advantages of good solderability, high reliability and excellent mechanical properties. As alternatives, the mainst...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C13/00C22C1/03B23K35/24
Inventor 黄家强肖德成刘家党景龙
Owner 深圳市同方电子新材料有限公司
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