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A kind of preparation method of nano-silver solder paste with high wettability

A wettability, nano-silver technology, applied in the direction of welding equipment, manufacturing tools, welding media, etc., can solve the problems affecting the sintering density interconnection strength and reliability of nano-silver solder paste, poor wettability of lead-free solder, Insufficient contact and other problems, to achieve the effect of improving connection strength and reliability, easy printing, and tight contact

Active Publication Date: 2020-04-14
GUILIN UNIV OF ELECTRONIC TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] For traditional interconnect materials such as Sn3Ag0.5Cu lead-free solder, the printing performance is not good due to the poor wettability of lead-free solder, which is also the biggest obstacle restricting its lead-free process; poor wettability Not only is it easy to produce defects such as missed printing, uneven printing, and bridging in the process, but it is also easy to cause reliability problems such as virtual soldering, voids, and cracks during the interconnection process.
As a new type of interconnect material nano-silver solder paste, its functional phase silver has been widely concerned due to its excellent electrical and thermal conductivity, high melting point and sintering at low temperature; however, nano-silver solder paste also exists on the surface of the substrate. Or the contact between chips is not tight enough and it is difficult to print on the substrate and other poor wetting properties, which in turn affects the sintering density of nano-silver solder paste and its interconnection strength and reliability

Method used

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  • A kind of preparation method of nano-silver solder paste with high wettability

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preparation example Construction

[0024] figure 1 A preparation method of nano-silver solder paste with high wettability is shown, comprising the steps:

[0025] (1) Dissolve the silver nitrate solid in distilled water to prepare a silver nitrate aqueous solution with a concentration of 0.1~1mol / L.

[0026] (2) Mix the reducing agent, compound stabilizer, and dispersant and dissolve in distilled water to make a reducing solution. After stirring evenly, add a pH regulator dropwise to adjust the pH of the system to 3~7.

[0027] (3) Stir the reducing solution uniformly in a water bath at 30-60°C, then add the silver nitrate aqueous solution drop by drop, and after the addition is complete, the nano-silver particle slurry wrapped by the compound stabilizer can be obtained.

[0028] (4) The nano-silver particle slurry is washed and centrifuged for 2-3 times, and its viscosity is adjusted to obtain a nano-silver solder paste with good wettability.

[0029] In order to ensure that the reaction is complete, as a fu...

Embodiment 1

[0038] A preparation process of nano-silver solder paste, comprising the steps of:

[0039] (1) Weigh 1.00 g of silver nitrate solid and dissolve it in 58.8 mL of distilled water to prepare a silver nitrate aqueous solution with a concentration of 0.1 mol / L.

[0040] (2) Then weigh 0.22g sodium borohydride (0.1mol / L), 0.75g 12-3-12 type Gemini (gemini) quaternary ammonium salt, 0.75g PVP, 0.10g sodium hexametaphosphate and dissolve them in 57.8mL distilled water 5 groups of the same reducing solution were prepared in the same solution, wherein the amount of sodium borohydride was 4 times the theoretical amount, the total mass of Gemini (gemini) quaternary ammonium salt and PVP was 1.5 times the mass of silver nitrate, and the mass of sodium hexametaphosphate was 0.1 times the mass of silver nitrate. Stir evenly to make it dissolve completely, then add a certain amount of dilute nitric acid dropwise to adjust the pH value of the system to 5.

[0041] (3) Stir the reducing sol...

Embodiment 2

[0044] According to the same method as in Example 1, under the constant condition of the total mass of the compound stabilizer, by changing the mass ratio of each component of the compound stabilizer, by 12-3-12 type Gemini (gemini) quaternary ammonium salt: PVP=1 : 1 becomes 12-3-12 type Gemini (gemini) quaternary ammonium salt: PVP=2:1, and sodium borohydride is used as reducing agent, 12-3-12 type Gemini (gemini) quaternary ammonium salt and polyvinylpyridine Nano-silver solder paste with good wetting performance was prepared by liquid-phase chemical reduction method in the same system with PVP as compound stabilizer and sodium hexametaphosphate as dispersant.

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Abstract

The invention discloses a preparation method for nano-silver welding paste with high wettability, relates to the technical field of nanometer material preparation, and aims at achieving the purpose ofproviding the nano-silver welding paste with good wettability, wherein contact between the nano-silver welding paste and a chip is tighter, and therefore the connection strength and the reliability are improved. By means of the method, sodium borohydride, 12-3-12 type Gemini quaternary ammonium salt, polyvinyl pyrrolidone (PVP) and sodium hexametaphosphate are mixed and prepared into a reductionsolution, dilute nitric acid is dropwise added to adjust the PH value, and under magnetic stirring, a silver nitrate solution is added into the reduction solution so that liquid phase chemical reduction can be carried out to obtain the nano-silver welding paste. According to the technical scheme, the wettability of the nano-silver welding paste can be improved, contact between the nano-silver welding paste and the chip can be tighter, and the sintering compactness, the connection strength and the reliability of the nano-silver welding paste can be improved.

Description

technical field [0001] The invention relates to the technical field of preparation of nanometer materials, in particular to a preparation method of nano silver solder paste with high wettability. Background technique [0002] Wettability is the ability of a fluid phase to preferentially wet the solid surface when two immiscible fluids appear on the surface of a solid medium. In electronic packaging, wetting is a measure of the ability of liquid solder to spread on the surface of a solid substrate, such as the process of fully expanding and uniformly spreading molten lead-free solder on the surface of a solid pad. [0003] For traditional interconnect materials such as Sn3Ag0.5Cu lead-free solder, the printing performance is not good due to the poor wettability of lead-free solder, which is also the biggest obstacle restricting its lead-free process; poor wettability Not only are defects such as missed printing, uneven printing, and bridging likely to occur in the process, b...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K35/40
Inventor 张平韦荣转姜雄袁朋曾建华蔡苗杨道国
Owner GUILIN UNIV OF ELECTRONIC TECH