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Lead free solder paste and application thereof

一种无铅焊膏、焊膏的技术,应用在焊接设备、焊接介质、焊接/切割介质/材料等方向,能够解决易破坏一次钎焊部、一次钎焊部熔融、Cu电极腐蚀等问题,达到良好焊料润湿性、锡球的发生量少、提高可靠性的效果

Active Publication Date: 2008-07-30
SENJU METAL IND CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Usually it needs to be heated at 130-160°C for about 30 minutes to harden the resin, which seriously hinders the production efficiency due to the long time spent
[0018] In addition, the solder alloys in the composition range of Sn-30 to 57Bi used in the examples of Patent Document 4 have temperatures close to the solidus and liquidus Therefore, when remelting in secondary soldering, if force is applied, not only the primary soldering part is easily damaged, but also the primary soldering part may be completely melted due to the heat of the electronic device.
Furthermore, compared with 63Sn-Pb eutectic solder, the silver plating layer or Ag-Pd plating layer covering the Cu electrode of the electronic component of this solder alloy is easily melted into the solder, so that the Cu electrode will be corroded during the current conduction.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment A

[0070] The melting point (solidus temperature and liquidus temperature) and the volume expansion rate (ratio of the volume at the liquidus temperature to the volume at the solidus temperature) at the time of melting of the solder alloys shown in Table 1 were measured. .

[0071] These solder alloy powders (average particle size: 25 to 35 μm) and flux A with the following composition (% is mass %) were mixed in the following proportions to prepare a solder paste, which was tested for self-alignment. tested. The results are shown in Table 1 together. In addition, the bisphenol A type epoxy resin used in the Example was all a liquid monomer (bis-phenol A diglycidylether (bis-phenolA diglycidylether)).

[0072] [Table 1]

[0073] No.

composition

Melting point (°C)

Expansion rate

(%)

self-alignment

NG number

(20

Among)

Bi

sn

Ag

Cu

Sb

In

...

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PUM

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Abstract

A solder paste composed of solder alloy powder and flux, the volume expansion rate of which is 0.5% or less when the solder alloy is melted, and the flux contains bisphenol A type epoxy resin and a hardening agent selected from carboxylic anhydrides and dicarboxylic acids agent, the solder paste can be used for high temperature solder applications. In terms of mass%, the solder alloy has the following alloy composition: 70-98 mass% of Bi; 0-0.5% of Ag, Cu, Sb, In, Zn, Ni, Cr, Fe, Mo, P, Ge and One or more elements selected from Ga; the balance is composed of Sn.

Description

technical field [0001] The invention relates to a lead-free solder paste suitable for soldering electronic components. Although the solder alloy used has a low melting point itself, the solder paste of the present invention can also be used in applications where existing high-temperature solders are suitable. Moreover, this invention also relates to the soldering method of the electronic component using this solder paste, and an electronic component. Background technique [0002] Conventionally, Pb-63Sn alloy (in this specification, the meaning of the number indicating the alloy composition means mass %), that is, eutectic solder, has been mainly used for soldering of electronic components. The melting point of eutectic solder (because it is eutectic solder, the solidus temperature and liquidus temperature are the same) is low at 183°C. Generally, the liquidus temperature of the solder +20-50°C is considered to be a reasonable brazing temperature, so the brazing temperatur...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K35/26B23K35/363C22C12/00H05K3/34B23K1/00B23K101/42B22F1/10B22F1/103
CPCB23K35/0244B23K35/025B23K35/264B23K35/3613B23K35/362C22C12/00H05K3/3463Y10T428/31678H05K3/3485B22F1/10B22F1/103
Inventor 渡边静晴高冈英清中野公介清野雅文稻叶耕
Owner SENJU METAL IND CO LTD
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