Flux

A technology of flux and solder paste, applied in the direction of welding medium, welding equipment, welding/cutting medium/material, etc., to achieve the effect of reducing cost, high reliability, and inhibiting migration

Inactive Publication Date: 2013-11-20
SENJU METAL IND CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] However, when a crack occurs on the flux residue, moisture infiltrates into the flux residue from the damaged part of the flux residue, and this moisture becomes a main factor for inducing migration.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0034] The fluxes of Examples and Comparative Examples were prepared according to the compositions shown in the table below, and solder pastes were prepared using the fluxes of Examples and Comparative Examples to compare the effect of preventing migration based on the presence or absence of addition of phosphate ester. In addition, the relationship between the amount of added phosphate ester and the properties of flux residues was compared.

[0035] (1) Composition of flux

[0036] The fluxes of Examples and Comparative Examples were prepared according to the compositions shown in Table 1 and Table 2 below, and 89% by mass of solder powder (composition: Sn-3Ag-0.5Cu, particle size: 25-36 μm) way to prepare solder paste. In addition, the composition ratio in Table 1 and Table 2 is mass %.

[0037] [Table 1]

[0038]

Example 1

Example 2

Example 3

Example 4

Example 5

Example 6

Rosin

50%

50%

50%

50%

50%

50%

...

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PUM

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Abstract

Provided is a flux that allows the occurrence of migration to be reliably suppressed in a soldered part where a flux residue is formed. The flux is mixed with a solder powder to produce a solder paste, wherein the flux includes a phosphate ester in an amount at which the ester is adsorbed on the surface of a soldered part during soldering and forms a hydrophobic coating. The phosphate ester is preferably added in an amount of from at least 1 mass% to less than 30 mass%. The phosphate ester is preferably 2-ethylhexyl phosphate, monoisodecyl phosphate, monobutyl phosphate, dibutyl phosphate, monolauryl phosphate, monostearyl phosphate, monooleyl phosphate, tetracosyl phosphate, or bis(2-ethylhexyl)phosphate.

Description

technical field [0001] The present invention relates to a flux mixed with solder powder, and more particularly to a flux having an effect of preventing post-soldering migration from occurring. Background technique [0002] On a substrate such as a printed circuit board on which electronic components are mounted, electrodes are formed corresponding to terminals such as leads of the electronic components. The fixing and electrical connection of the electronic components and the substrate are mainly performed by soldering. In such a substrate, ion migration (electrochemical migration) may occur at the soldered portion between the terminal of the electronic component and the electrode of the substrate due to, for example, water droplets adhering between electrodes to which DC voltage is applied. [0003] Ion migration (hereinafter referred to as migration) means that between electrodes to which a DC voltage is applied, metal ions eluted from the anode receive electrons at the c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K35/363
CPCB23K35/262B23K35/025B23K35/362B23K35/3618B23K35/3601B23K35/383B23K35/3612B23K35/3613
Inventor 水口大辅杉浦达也
Owner SENJU METAL IND CO LTD
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