Low-temperature halogenide-free high-activity soldering tin paste

A technology of solder paste and halide, applied in the direction of welding medium, welding equipment, welding/cutting medium/material, etc., can solve the problems of multi-corrosion residue, destruction of atmospheric ozone layer, and influence on product reliability, etc., to achieve long-term benefits Effects of time printing, life extension, and suppression of solder ball formation

Inactive Publication Date: 2008-12-24
DONGGUAN YONGAN TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, most of the fluxes used to prepare solder paste in the electronics industry contain halide activators, which not only have many residues but also are highly corrosive, which will seriously affect the reliability of products
At the same time, the use of halogen-containing compounds has a serious damaging effect on the atmospheric ozone layer, which has brought great damage to the human ecological environment, and has been restricted by the United Nations for production and use.

Method used

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  • Low-temperature halogenide-free high-activity soldering tin paste

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1～3 and comparative Embodiment 1～2

[0032] The spherical powder of 88.5% Sn-Bi based lead-free solder alloy having the following composition: 42% Sn and 58% Bi, the rosin-based flux had the composition shown in Table 1. Each component is weighed in proportion, heated and dissolved to form a homogeneous solution, and stored at 5-10°C for later use.

[0033] Using the solder paste prepared above, a soldering test was carried out in a standard tin melting furnace, and the solderability (wettability) and the formation of solder balls were evaluated. The coating materials were copper plating and electroless nickel plating, respectively. The results are shown in Table 2

[0034] Table 1 flux formulation table

[0035] Flux composition, %

Example 1

Example 2

Example 3

Comparative example 1

Comparative example 2

polymerized rosin

50

48

48

46

48

Diethylene glycol hexyl ether

36

36

36

36

36

Succinic acid

3...

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PUM

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Abstract

The present invention relates to a low-temperature, halideless high-activity soldering paste, which contains a type of Sn-Bi-based leadless solder powder mixed with soldering flux, and wherein, the soldering flux contains at least one type of hydroxy alkylamine, the weight percentage of which is 0.5 percent to 20 percent. The soldering paste has the advantages of good viscosity stability, colorless and transparent residues and low corrosiveness and shows excellent solderability, and moreover, the soldering paste has good solderability on standard and hard-to-solder surfaces, particularly under a low soldering temperature. The soldering paste is applicable to the soldering of electronic elements with a bad thermal shock-resisting property.

Description

technical field [0001] The invention relates to solder paste for welding electronic devices, in particular to low-temperature lead-free halide-free high-activity solder paste based on Sn-Bi alloy. Background technique [0002] Sn-Pb alloys have been used as welding materials since ancient times. In recent years, in order to reduce the pollution of lead and its compounds to the ecological environment, countries around the world have successively developed lead-free solder pastes to replace traditional tin-lead solder pastes. Among them, Ag-containing Sn-based solders, such as Sn-Ag and Sn-Ag-Cu alloys, have the advantage of being easy to handle due to their relatively good wettability as lead-free solders. However, Sn-Ag-based lead-free solder has a melting point of about 220°C, which is about 30-40°C higher than that of the eutectic Sn-Pb alloy, so the operating temperature also becomes correspondingly higher, which is not suitable for thermal shock resistance. Poor solder...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K35/362
Inventor 吴国齐宣英男
Owner DONGGUAN YONGAN TECH
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